diff --git a/src/installer/tests/HostActivation.Tests/DependencyResolution/ResolveComponentDependencies.cs b/src/installer/tests/HostActivation.Tests/DependencyResolution/ResolveComponentDependencies.cs
index f931594ccd31a5..ccf81e7cf8760f 100644
--- a/src/installer/tests/HostActivation.Tests/DependencyResolution/ResolveComponentDependencies.cs
+++ b/src/installer/tests/HostActivation.Tests/DependencyResolution/ResolveComponentDependencies.cs
@@ -74,7 +74,7 @@ public void ComponentWithNoDependenciesCaseChangedOnAsm()
             // Rename
             File.Move(fileName, changeFile);
 
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            if (OperatingSystem.IsWindows())
             {
                 sharedTestState.RunComponentResolutionTest(component)
                     .Should().Pass()
@@ -84,7 +84,7 @@ public void ComponentWithNoDependenciesCaseChangedOnAsm()
                     .And.HaveStdErrContaining($"deps='{component.DepsJson}'")
                     .And.HaveStdErrContaining($"mgd_app='{component.AppDll}'");
             }
-            else if(RuntimeInformation.IsOSPlatform(OSPlatform.OSX))
+            else if(OperatingSystem.IsMacOS())
             {
                 sharedTestState.RunComponentResolutionTest(component)
                     .Should().Pass()
@@ -131,7 +131,7 @@ public void ComponentWithNoDependenciesCaseChangedOnDepsAndAsm()
             File.Move(fileName, changeFile);
             File.Move(component.DepsJson, changeDepsFile);
 
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            if (OperatingSystem.IsWindows())
             {
                 sharedTestState.RunComponentResolutionTest(component)
                     .Should().Pass()
@@ -141,7 +141,7 @@ public void ComponentWithNoDependenciesCaseChangedOnDepsAndAsm()
                     .And.HaveStdErrContaining($"deps='{component.DepsJson}'")
                     .And.HaveStdErrContaining($"mgd_app='{component.AppDll}'");
             }
-            else if(RuntimeInformation.IsOSPlatform(OSPlatform.OSX))
+            else if(OperatingSystem.IsMacOS())
             {
                 sharedTestState.RunComponentResolutionTest(component)
                     .Should().Pass()
@@ -189,7 +189,7 @@ public void ComponentWithNoDependenciesNoDepsCaseChangedOnAsm()
             // Delete deps
             File.Delete(component.DepsJson);
 
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            if (OperatingSystem.IsWindows())
             {
                 sharedTestState.RunComponentResolutionTest(component)
                     .Should().Pass()
@@ -199,7 +199,7 @@ public void ComponentWithNoDependenciesNoDepsCaseChangedOnAsm()
                     .And.HaveStdErrContaining($"deps='{component.DepsJson}'")
                     .And.HaveStdErrContaining($"mgd_app='{component.AppDll}'");
             }
-            else if(RuntimeInformation.IsOSPlatform(OSPlatform.OSX))
+            else if(OperatingSystem.IsMacOS())
             {
                 sharedTestState.RunComponentResolutionTest(component)
                     .Should().Pass()
diff --git a/src/installer/tests/HostActivation.Tests/FrameworkResolution/MultipleHives.cs b/src/installer/tests/HostActivation.Tests/FrameworkResolution/MultipleHives.cs
index 2b09b95c8ec95b..0a12cd2640ce9b 100644
--- a/src/installer/tests/HostActivation.Tests/FrameworkResolution/MultipleHives.cs
+++ b/src/installer/tests/HostActivation.Tests/FrameworkResolution/MultipleHives.cs
@@ -21,14 +21,9 @@ public MultipleHives(SharedTestState sharedState)
         }
 
         [Fact]
+        [PlatformSpecific(TestPlatforms.Windows)] // Multiple hives are only supported on Windows.
         public void FrameworkHiveSelection_GlobalHiveWithBetterMatch()
         {
-            if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
-            {
-                // Multiple hives are only supported on Windows.
-                return;
-            }
-
             RunTest(
                 runtimeConfig => runtimeConfig
                     .WithFramework(MicrosoftNETCoreApp, "5.0.0"))
@@ -36,14 +31,9 @@ public void FrameworkHiveSelection_GlobalHiveWithBetterMatch()
         }
 
         [Fact]
+        [PlatformSpecific(TestPlatforms.Windows)] // Multiple hives are only supported on Windows.
         public void FrameworkHiveSelection_MainHiveWithBetterMatch()
         {
-            if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
-            {
-                // Multiple hives are only supported on Windows.
-                return;
-            }
-
             RunTest(
                 runtimeConfig => runtimeConfig
                     .WithFramework(MicrosoftNETCoreApp, "6.0.0"))
@@ -51,14 +41,9 @@ public void FrameworkHiveSelection_MainHiveWithBetterMatch()
         }
 
         [Fact]
+        [PlatformSpecific(TestPlatforms.Windows)] // Multiple hives are only supported on Windows.
         public void FrameworkHiveSelection_CurrentDirectoryIsIgnored()
         {
-            if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
-            {
-                // Multiple hives are only supported on Windows.
-                return;
-            }
-
             RunTest(
                 SharedState.DotNetMainHive,
                 SharedState.FrameworkReferenceApp,
diff --git a/src/installer/tests/HostActivation.Tests/HostVersionCompatibility.cs b/src/installer/tests/HostActivation.Tests/HostVersionCompatibility.cs
index d352a8bdb32f07..ba80b0c7caad29 100644
--- a/src/installer/tests/HostActivation.Tests/HostVersionCompatibility.cs
+++ b/src/installer/tests/HostActivation.Tests/HostVersionCompatibility.cs
@@ -138,9 +138,9 @@ private static bool IsRidSupported()
         {
             // Some current Linux RIDs are not supported in 2.0\2.1; just test for Ubuntu 16.
             return (
-                RuntimeInformation.IsOSPlatform(OSPlatform.Windows) ||
-                RuntimeInformation.IsOSPlatform(OSPlatform.OSX) ||
-                (RuntimeInformation.IsOSPlatform(OSPlatform.Linux) && RuntimeInformation.RuntimeIdentifier == "ubuntu.16.04-x64")
+                OperatingSystem.IsWindows() ||
+                OperatingSystem.IsMacOS() ||
+                (OperatingSystem.IsLinux() && RuntimeInformation.RuntimeIdentifier == "ubuntu.16.04-x64")
             );
         }
 
diff --git a/src/installer/tests/HostActivation.Tests/MultilevelSDKLookup.cs b/src/installer/tests/HostActivation.Tests/MultilevelSDKLookup.cs
index d3ddfa2553d731..97b3387604b623 100644
--- a/src/installer/tests/HostActivation.Tests/MultilevelSDKLookup.cs
+++ b/src/installer/tests/HostActivation.Tests/MultilevelSDKLookup.cs
@@ -89,14 +89,9 @@ public void Dispose()
         }
 
         [Fact]
+        [PlatformSpecific(TestPlatforms.Windows)] // Multi-level lookup is only supported on Windows.
         public void SdkMultilevelLookup_Global_Json_Single_Digit_Patch_Rollup()
         {
-            if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
-            {
-                // Multi-level lookup is only supported on Windows.
-                return;
-            }
-
             // Set specified SDK version = 9999.3.4-global-dummy
             SetGlobalJsonVersion("SingleDigit-global.json");
 
@@ -264,14 +259,9 @@ public void SdkMultilevelLookup_Global_Json_Single_Digit_Patch_Rollup()
         }
 
         [Fact]
+        [PlatformSpecific(TestPlatforms.Windows)] // Multi-level lookup is only supported on Windows.
         public void SdkMultilevelLookup_Global_Json_Two_Part_Patch_Rollup()
         {
-            if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
-            {
-                // Multi-level lookup is only supported on Windows.
-                return;
-            }
-
             // Set specified SDK version = 9999.3.304-global-dummy
             SetGlobalJsonVersion("TwoPart-global.json");
 
@@ -444,14 +434,9 @@ public void SdkMultilevelLookup_Global_Json_Two_Part_Patch_Rollup()
         }
 
         [Fact]
+        [PlatformSpecific(TestPlatforms.Windows)] // Multi-level lookup is only supported on Windows.
         public void SdkMultilevelLookup_Precedential_Order()
         {
-            if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
-            {
-                // Multi-level lookup is only supported on Windows.
-                return;
-            }
-
             WriteEmptyGlobalJson();
 
             // Add SDK versions
@@ -498,6 +483,7 @@ public void SdkMultilevelLookup_Precedential_Order()
         }
 
         [Fact]
+        [PlatformSpecific(TestPlatforms.Windows)] // Multi-level lookup is only supported on Windows.
         public void SdkMultilevelLookup_RegistryAccess()
         {
             // The purpose of this test is to verify that the product uses correct code to access
@@ -511,12 +497,6 @@ public void SdkMultilevelLookup_RegistryAccess()
             // different registry key, inside the HKEY_CURRENT_USER hive which is writable without admin.
             // Note that the test creates a unique key (based on PID) for every run, to avoid collisions between parallel running tests.
 
-            if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
-            {
-                // Multi-level lookup is only supported on Windows.
-                return;
-            }
-
             WriteEmptyGlobalJson();
 
             using (var registeredInstallLocationOverride = new RegisteredInstallLocationOverride(DotNet.GreatestVersionHostFxrFilePath))
@@ -547,14 +527,9 @@ public void SdkMultilevelLookup_RegistryAccess()
         }
 
         [Fact]
+        [PlatformSpecific(TestPlatforms.Windows)] // Multi-level lookup is only supported on Windows.
         public void SdkMultilevelLookup_Must_Pick_The_Highest_Semantic_Version()
         {
-            if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
-            {
-                // Multi-level lookup is only supported on Windows.
-                return;
-            }
-
             WriteEmptyGlobalJson();
 
             // Add SDK versions
diff --git a/src/installer/tests/HostActivation.Tests/MultilevelSharedFxLookup.cs b/src/installer/tests/HostActivation.Tests/MultilevelSharedFxLookup.cs
index f8b4e8bfd402d6..788963fa33e49b 100644
--- a/src/installer/tests/HostActivation.Tests/MultilevelSharedFxLookup.cs
+++ b/src/installer/tests/HostActivation.Tests/MultilevelSharedFxLookup.cs
@@ -129,14 +129,9 @@ public void Dispose()
         }
 
         [Fact]
+        [PlatformSpecific(TestPlatforms.Windows)] // Multi-level lookup is only supported on Windows.
         public void SharedMultilevelFxLookup_Must_Verify_Folders_in_the_Correct_Order()
         {
-            if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
-            {
-                // Multi-level lookup is only supported on Windows.
-                return;
-            }
-
             var fixture = SharedFxLookupPortableAppFixture
                 .Copy();
 
@@ -246,14 +241,9 @@ public void SharedMultilevelFxLookup_Must_Verify_Folders_in_the_Correct_Order()
         }
 
         [Fact]
+        [PlatformSpecific(TestPlatforms.Windows)] // Multi-level lookup is only supported on Windows.
         public void SharedMultilevelFxLookup_Must_Not_Roll_Forward_If_Framework_Version_Is_Specified_Through_Argument()
         {
-            if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
-            {
-                // Multi-level lookup is only supported on Windows.
-                return;
-            }
-
             var fixture = SharedFxLookupPortableAppFixture
                 .Copy();
 
diff --git a/src/installer/tests/HostActivation.Tests/NativeHostApis.cs b/src/installer/tests/HostActivation.Tests/NativeHostApis.cs
index a213579e5a7186..aaabf8e571bcd2 100644
--- a/src/installer/tests/HostActivation.Tests/NativeHostApis.cs
+++ b/src/installer/tests/HostActivation.Tests/NativeHostApis.cs
@@ -128,14 +128,9 @@ public SdkResolutionFixture(SharedTestState state)
         }
 
         [Fact]
+        [PlatformSpecific(TestPlatforms.Windows)] // Multi-level lookup is only supported on Windows.
         public void Hostfxr_get_available_sdks_with_multilevel_lookup()
         {
-            if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
-            {
-                // multilevel lookup is not supported on non-Windows
-                return;
-            }
-
             var f = new SdkResolutionFixture(sharedTestState);
 
             // With multi-level lookup (windows only): get local and global sdks sorted by ascending version,
@@ -322,14 +317,9 @@ public void Hostfxr_get_dotnet_environment_info_dotnet_root_only()
         }
 
         [Fact]
+        [PlatformSpecific(TestPlatforms.Windows)] // Multi-level lookup is only supported on Windows.
         public void Hostfxr_get_dotnet_environment_info_with_multilevel_lookup_with_dotnet_root()
         {
-            if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
-            {
-                // Only Windows supports multi-level lookup.
-                return;
-            }
-
             var f = new SdkResolutionFixture(sharedTestState);
             string expectedSdkVersions = string.Join(';', new[]
             {
@@ -406,14 +396,9 @@ public void Hostfxr_get_dotnet_environment_info_with_multilevel_lookup_with_dotn
         }
 
         [Fact]
+        [PlatformSpecific(TestPlatforms.Windows)] // Multi-level lookup is only supported on Windows.
         public void Hostfxr_get_dotnet_environment_info_with_multilevel_lookup_only()
         {
-            if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
-            {
-                // Only Windows supports multi-level lookup.
-                return;
-            }
-
             var f = new SdkResolutionFixture(sharedTestState);
             string expectedSdkVersions = string.Join(';', new[]
             {
@@ -558,7 +543,7 @@ public SharedTestState()
                     .EnsureRestored()
                     .PublishProject();
 
-                if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+                if (!OperatingSystem.IsWindows())
                 {
                     BreadcrumbLocation = Path.Combine(
                         PortableAppWithExceptionFixture.TestProject.OutputDirectory,
diff --git a/src/installer/tests/HostActivation.Tests/NativeHosting/ApplicationExecution.cs b/src/installer/tests/HostActivation.Tests/NativeHosting/ApplicationExecution.cs
index 9c0d1da0a63ea5..cec6b1030e7c7c 100644
--- a/src/installer/tests/HostActivation.Tests/NativeHosting/ApplicationExecution.cs
+++ b/src/installer/tests/HostActivation.Tests/NativeHosting/ApplicationExecution.cs
@@ -2,6 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using Microsoft.DotNet.Cli.Build.Framework;
+using System;
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
@@ -101,7 +102,7 @@ public static FluentAssertions.AndConstraint<CommandResultAssertions> ExecuteApp
         public static FluentAssertions.AndConstraint<CommandResultAssertions> ExecuteApplicationWithException(this CommandResultAssertions assertion, string hostPath, string appPath)
         {
             var constraint = assertion.ExecuteApplication(hostPath, appPath);
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            if (OperatingSystem.IsWindows())
             {
                 return constraint.And.HaveStdOutContaining($"hostfxr_run_app threw exception: 0x{Constants.ErrorCode.COMPlusException.ToString("x")}");
             }
diff --git a/src/installer/tests/HostActivation.Tests/NativeHosting/Comhost.cs b/src/installer/tests/HostActivation.Tests/NativeHosting/Comhost.cs
index ff15e58b878a44..d48d8439008966 100644
--- a/src/installer/tests/HostActivation.Tests/NativeHosting/Comhost.cs
+++ b/src/installer/tests/HostActivation.Tests/NativeHosting/Comhost.cs
@@ -1,6 +1,7 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+using System;
 using System.Collections.Generic;
 using System.IO;
 using System.Reflection.Metadata;
@@ -22,17 +23,12 @@ public Comhost(SharedTestState sharedTestState)
         }
 
         [Theory]
+        [PlatformSpecific(TestPlatforms.Windows)] // COM activation is only supported on Windows
         [InlineData(1, true)]
         [InlineData(10, true)]
         [InlineData(10, false)]
         public void ActivateClass(int count, bool synchronous)
         {
-            if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
-            {
-                // COM activation is only supported on Windows
-                return;
-            }
-
             string [] args = {
                 "comhost",
                 synchronous ? "synchronous" : "concurrent",
@@ -53,14 +49,9 @@ public void ActivateClass(int count, bool synchronous)
         }
 
         [Fact]
+        [PlatformSpecific(TestPlatforms.Windows)] // COM activation is only supported on Windows
         public void ActivateClass_IgnoreAppLocalHostFxr()
         {
-            if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
-            {
-                // COM activation is only supported on Windows
-                return;
-            }
-
             using (var fixture = sharedState.ComLibraryFixture.Copy())
             {
                 File.WriteAllText(Path.Combine(fixture.TestProject.BuiltApp.Location, "hostfxr.dll"), string.Empty);
@@ -86,14 +77,9 @@ public void ActivateClass_IgnoreAppLocalHostFxr()
         }
 
         [Fact]
+        [PlatformSpecific(TestPlatforms.Windows)] // COM activation is only supported on Windows
         public void ActivateClass_ValidateIErrorInfoResult()
         {
-            if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
-            {
-                // COM activation is only supported on Windows
-                return;
-            }
-
             using (var fixture = sharedState.ComLibraryFixture.Copy())
             {
                 string missingRuntimeConfig = Path.Combine(fixture.TestProject.BuiltApp.Location,
@@ -121,14 +107,9 @@ public void ActivateClass_ValidateIErrorInfoResult()
         }
 
         [Fact]
+        [PlatformSpecific(TestPlatforms.Windows)] // COM activation is only supported on Windows
         public void LoadTypeLibraries()
         {
-            if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
-            {
-                // COM activation is only supported on Windows
-                return;
-            }
-
             using (var fixture = sharedState.ComLibraryFixture.Copy())
             {
                 var comHost = Path.Combine(
@@ -165,7 +146,7 @@ public class SharedTestState : SharedTestStateBase
 
             public SharedTestState()
             {
-                if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+                if (!OperatingSystem.IsWindows())
                 {
                     // COM activation is only supported on Windows
                     return;
diff --git a/src/installer/tests/HostActivation.Tests/NativeHosting/ComhostSideBySide.cs b/src/installer/tests/HostActivation.Tests/NativeHosting/ComhostSideBySide.cs
index 3732e545f4807d..623f93a8fdce5d 100644
--- a/src/installer/tests/HostActivation.Tests/NativeHosting/ComhostSideBySide.cs
+++ b/src/installer/tests/HostActivation.Tests/NativeHosting/ComhostSideBySide.cs
@@ -1,6 +1,7 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+using System;
 using System.Collections.Generic;
 using System.IO;
 using System.Reflection.Metadata;
@@ -22,14 +23,9 @@ public ComhostSideBySide(SharedTestState sharedTestState)
         }
 
         [Fact]
+        [PlatformSpecific(TestPlatforms.Windows)] // COM activation is only supported on Windows
         public void ActivateClass()
         {
-            if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
-            {
-                // COM activation is only supported on Windows
-                return;
-            }
-
             string [] args = {
                 "activation",
                 sharedState.ClsidString
@@ -46,14 +42,9 @@ public void ActivateClass()
         }
 
         [Fact]
+        [PlatformSpecific(TestPlatforms.Windows)] // COM activation is only supported on Windows
         public void LocateEmbeddedTlb()
         {
-            if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
-            {
-                // COM activation is only supported on Windows
-                return;
-            }
-
             string [] args = {
                 "typelib_lookup",
                 sharedState.TypeLibId
@@ -77,7 +68,7 @@ public class SharedTestState : Comhost.SharedTestState
 
             public SharedTestState()
             {
-                if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+                if (!OperatingSystem.IsWindows())
                 {
                     // COM activation is only supported on Windows
                     return;
diff --git a/src/installer/tests/HostActivation.Tests/NativeHosting/GetFunctionPointer.cs b/src/installer/tests/HostActivation.Tests/NativeHosting/GetFunctionPointer.cs
index 0ac123167732b2..1f741d696e29f5 100644
--- a/src/installer/tests/HostActivation.Tests/NativeHosting/GetFunctionPointer.cs
+++ b/src/installer/tests/HostActivation.Tests/NativeHosting/GetFunctionPointer.cs
@@ -2,6 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using Microsoft.DotNet.Cli.Build.Framework;
+using System;
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
@@ -268,7 +269,7 @@ public static FluentAssertions.AndConstraint<CommandResultAssertions> ExecuteFun
         public static FluentAssertions.AndConstraint<CommandResultAssertions> ExecuteFunctionPointerWithException(this CommandResultAssertions assertion, string methodName, int functionPointerCallCount)
         {
             var constraint = assertion.ExecuteFunctionPointer(methodName, functionPointerCallCount);
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            if (OperatingSystem.IsWindows())
             {
                 return constraint.And.HaveStdOutContaining($"{methodName} delegate threw exception: 0x{Constants.ErrorCode.COMPlusException.ToString("x")}");
             }
diff --git a/src/installer/tests/HostActivation.Tests/NativeHosting/LoadAssemblyAndGetFunctionPointer.cs b/src/installer/tests/HostActivation.Tests/NativeHosting/LoadAssemblyAndGetFunctionPointer.cs
index 53e9eeb52aec93..f329de2229c29a 100644
--- a/src/installer/tests/HostActivation.Tests/NativeHosting/LoadAssemblyAndGetFunctionPointer.cs
+++ b/src/installer/tests/HostActivation.Tests/NativeHosting/LoadAssemblyAndGetFunctionPointer.cs
@@ -2,6 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using Microsoft.DotNet.Cli.Build.Framework;
+using System;
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
@@ -284,7 +285,7 @@ public static FluentAssertions.AndConstraint<CommandResultAssertions> ExecuteCom
         public static FluentAssertions.AndConstraint<CommandResultAssertions> ExecuteComponentEntryPointWithException(this CommandResultAssertions assertion, string methodName, int componentCallCount)
         {
             var constraint = assertion.ExecuteComponentEntryPoint(methodName, componentCallCount);
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            if (OperatingSystem.IsWindows())
             {
                 return constraint.And.HaveStdOutContaining($"{methodName} delegate threw exception: 0x{Constants.ErrorCode.COMPlusException.ToString("x")}");
             }
diff --git a/src/installer/tests/HostActivation.Tests/NativeHosting/Nethost.cs b/src/installer/tests/HostActivation.Tests/NativeHosting/Nethost.cs
index c8f5106b166637..0f18161b026827 100644
--- a/src/installer/tests/HostActivation.Tests/NativeHosting/Nethost.cs
+++ b/src/installer/tests/HostActivation.Tests/NativeHosting/Nethost.cs
@@ -2,6 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using Microsoft.DotNet.Cli.Build.Framework;
+using System;
 using System.IO;
 using System.Runtime.InteropServices;
 using Xunit;
@@ -178,6 +179,7 @@ public void GetHostFxrPath_HostFxrAlreadyLoaded()
         }
 
         [Theory]
+        [SkipOnPlatform(TestPlatforms.Windows, "This test targets the install_location config file which is only used on Linux and macOS.")]
         [InlineData("{0}", true)]
         [InlineData("{0}\n", true)]
         [InlineData("{0}\nSome other text", true)]
@@ -188,12 +190,6 @@ public void GetHostFxrPath_HostFxrAlreadyLoaded()
         [InlineData("{0} ", false)]
         public void GetHostFxrPath_InstallLocationFile(string value, bool shouldPass)
         {
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
-            {
-                // This test targets the install_location config file which is only used on Linux and macOS.
-                return;
-            }
-
             string installLocation = Path.Combine(sharedState.ValidInstallRoot, "dotnet");
 
             using (var registeredInstallLocationOverride = new RegisteredInstallLocationOverride(sharedState.NethostPath))
diff --git a/src/installer/tests/HostActivation.Tests/PortableAppActivation.cs b/src/installer/tests/HostActivation.Tests/PortableAppActivation.cs
index 79ead8f05f3b07..14060b5e944bfa 100644
--- a/src/installer/tests/HostActivation.Tests/PortableAppActivation.cs
+++ b/src/installer/tests/HostActivation.Tests/PortableAppActivation.cs
@@ -456,16 +456,11 @@ public void AppHost_CLI_FrameworkDependent_MissingRuntimeFramework_ErrorReported
         }
 
         [Theory]
+        [PlatformSpecific(TestPlatforms.Windows)] // GUI app host is only supported on Windows.
         [InlineData(true)]
         [InlineData(false)]
         public void AppHost_GUI_FrameworkDependent_MissingRuntimeFramework_ErrorReportedInDialog(bool missingHostfxr)
         {
-            if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
-            {
-                // GUI app host is only supported on Windows.
-                return;
-            }
-
             var fixture = sharedTestState.PortableAppFixture_Built
                 .Copy();
 
@@ -521,13 +516,9 @@ public void AppHost_GUI_FrameworkDependent_MissingRuntimeFramework_ErrorReported
         }
 
         [Fact]
+        [PlatformSpecific(TestPlatforms.Windows)] // GUI app host is only supported on Windows.
         public void AppHost_GUI_NoCustomErrorWriter_FrameworkMissing_ErrorReportedInDialog()
         {
-            if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
-            {
-                return;
-            }
-
             var fixture = sharedTestState.PortableAppFixture_Built
                 .Copy();
 
@@ -564,14 +555,9 @@ public void AppHost_GUI_NoCustomErrorWriter_FrameworkMissing_ErrorReportedInDial
         }
 
         [Fact]
+        [PlatformSpecific(TestPlatforms.Windows)] // GUI app host is only supported on Windows.
         public void AppHost_GUI_FrameworkDependent_DisabledGUIErrors_DialogNotShown()
         {
-            if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
-            {
-                // GUI app host is only supported on Windows.
-                return;
-            }
-
             var fixture = sharedTestState.PortableAppFixture_Built
                 .Copy();
 
diff --git a/src/installer/tests/HostActivation.Tests/RegisteredInstallLocationOverride.cs b/src/installer/tests/HostActivation.Tests/RegisteredInstallLocationOverride.cs
index 33ce9f81c3e940..7a30c5d6fd08dc 100644
--- a/src/installer/tests/HostActivation.Tests/RegisteredInstallLocationOverride.cs
+++ b/src/installer/tests/HostActivation.Tests/RegisteredInstallLocationOverride.cs
@@ -25,7 +25,7 @@ public RegisteredInstallLocationOverride(string productBinaryPath)
         {
             _testOnlyProductBehavior = TestOnlyProductBehavior.Enable(productBinaryPath);
 
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            if (OperatingSystem.IsWindows())
             {
                 // To test registered installs, we need a registry key which is:
                 // - writable without admin access - so that the tests don't require admin to run
@@ -63,7 +63,7 @@ public RegisteredInstallLocationOverride(string productBinaryPath)
 
         public void SetInstallLocation(string installLocation, string architecture)
         {
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            if (OperatingSystem.IsWindows())
             {
                 using (RegistryKey dotnetLocationKey = key.CreateSubKey($@"Setup\InstalledVersions\{architecture}"))
                 {
@@ -78,7 +78,7 @@ public void SetInstallLocation(string installLocation, string architecture)
 
         public void Dispose()
         {
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            if (OperatingSystem.IsWindows())
             {
                 parentKey.DeleteSubKeyTree(keyName, throwOnMissingSubKey: false);
                 key.Dispose();
@@ -110,7 +110,7 @@ public static Command ApplyRegisteredInstallLocationOverride(
                 return command;
             }
 
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            if (OperatingSystem.IsWindows())
             {
                 return command.EnvironmentVariable(
                     Constants.TestOnlyEnvironmentVariables.RegistryPath,
diff --git a/src/installer/tests/HostActivation.Tests/StandaloneAppActivation.cs b/src/installer/tests/HostActivation.Tests/StandaloneAppActivation.cs
index 995aa5f64b9a2c..b7ec6eb9688916 100644
--- a/src/installer/tests/HostActivation.Tests/StandaloneAppActivation.cs
+++ b/src/installer/tests/HostActivation.Tests/StandaloneAppActivation.cs
@@ -78,7 +78,7 @@ public void Running_Publish_Output_Standalone_EXE_with_Unbound_AppHost_Fails()
                 .Execute(fExpectedToFail: true)
                 .ExitCode;
 
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            if (OperatingSystem.IsWindows())
             {
                 exitCode.Should().Be(-2147450731);
             }
@@ -107,7 +107,7 @@ public void Running_Publish_Output_Standalone_EXE_By_Renaming_dotnet_exe_Fails()
                 .Execute(fExpectedToFail: true)
                 .ExitCode;
 
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            if (OperatingSystem.IsWindows())
             {
                 exitCode.Should().Be(-2147450748);
             }
@@ -237,14 +237,9 @@ public void Running_Publish_Output_Standalone_EXE_with_Bound_AppHost_Succeeds()
         }
 
         [Fact]
+        [PlatformSpecific(TestPlatforms.Windows)] // GUI app host is only supported on Windows.
         public void Running_AppHost_with_GUI_No_Console()
         {
-            if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
-            {
-                // GUI app host is only supported on Windows.
-                return;
-            }
-
             var fixture = sharedTestState.StandaloneAppFixture_Published
                 .Copy();
 
@@ -263,14 +258,9 @@ public void Running_AppHost_with_GUI_No_Console()
         }
 
         [Fact]
+        [PlatformSpecific(TestPlatforms.Windows)] // GUI app host is only supported on Windows.
         public void Running_AppHost_with_GUI_Traces()
         {
-            if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
-            {
-                // GUI app host is only supported on Windows.
-                return;
-            }
-
             var fixture = sharedTestState.StandaloneAppFixture_Published
                 .Copy();
 
diff --git a/src/installer/tests/HostActivation.Tests/WindowsSpecificBehavior.cs b/src/installer/tests/HostActivation.Tests/WindowsSpecificBehavior.cs
index 4df829ddc049e8..b97f38304f7538 100644
--- a/src/installer/tests/HostActivation.Tests/WindowsSpecificBehavior.cs
+++ b/src/installer/tests/HostActivation.Tests/WindowsSpecificBehavior.cs
@@ -18,14 +18,9 @@ public WindowsSpecificBehavior(SharedTestState fixture)
         }
 
         [Fact]
+        [PlatformSpecific(TestPlatforms.Windows)] // Manifests are only supported on Windows OSes.
         public void MuxerRunsPortableAppWithoutWindowsOsShims()
         {
-            if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
-            {
-                // Manifests are only supported on Windows OSes.
-                return;
-            }
-
             TestProjectFixture portableAppFixture = sharedTestState.TestWindowsOsShimsAppFixture.Copy();
 
             portableAppFixture.BuiltDotnet.Exec(portableAppFixture.TestProject.AppDll)
@@ -37,13 +32,9 @@ public void MuxerRunsPortableAppWithoutWindowsOsShims()
         }
 
         [Fact]
+        [PlatformSpecific(TestPlatforms.Windows)]
         public void FrameworkDependent_DLL_LongPath_Succeeds()
         {
-            if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
-            {
-                return;
-            }
-
             // Long paths must also be enabled via a machine-wide setting. Only run the test if it is enabled.
             using (RegistryKey key = Registry.LocalMachine.OpenSubKey(@"SYSTEM\CurrentControlSet\Control\FileSystem"))
             {
diff --git a/src/installer/tests/Microsoft.NET.HostModel.Tests/AppHost.Bundle.Tests/BundleExtractToSpecificPath.cs b/src/installer/tests/Microsoft.NET.HostModel.Tests/AppHost.Bundle.Tests/BundleExtractToSpecificPath.cs
index 33c895548b2195..4fd8156dcdc37c 100644
--- a/src/installer/tests/Microsoft.NET.HostModel.Tests/AppHost.Bundle.Tests/BundleExtractToSpecificPath.cs
+++ b/src/installer/tests/Microsoft.NET.HostModel.Tests/AppHost.Bundle.Tests/BundleExtractToSpecificPath.cs
@@ -76,7 +76,7 @@ private void Bundle_Extraction_To_Relative_Path_Succeeds(string relativePath, Bu
             // any forward slashes to the standard Windows dir separator ('\'), thus
             // failing to create directory trees for bundle extraction that use Unix
             // style dir separator in Windows.
-            if (relativePath == "foo/bar" && RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            if (relativePath == "foo/bar" && OperatingSystem.IsWindows())
                 return;
 
             var fixture = sharedTestState.TestFixture.Copy();
diff --git a/src/installer/tests/Microsoft.NET.HostModel.Tests/AppHost.Bundle.Tests/BundleLocalizedApp.cs b/src/installer/tests/Microsoft.NET.HostModel.Tests/AppHost.Bundle.Tests/BundleLocalizedApp.cs
index c1c8fbe28d9f8c..5471ed9b444916 100644
--- a/src/installer/tests/Microsoft.NET.HostModel.Tests/AppHost.Bundle.Tests/BundleLocalizedApp.cs
+++ b/src/installer/tests/Microsoft.NET.HostModel.Tests/AppHost.Bundle.Tests/BundleLocalizedApp.cs
@@ -26,7 +26,7 @@ public void Bundled_Localized_App_Run_Succeeds()
             var fixture = sharedTestState.TestFixture.Copy();
             var singleFile = BundleSelfContainedApp(fixture);
 
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            if (OperatingSystem.IsWindows())
             {
                 // Set code page to output unicode characters.
                 Command.Create("chcp 65001").Execute();
diff --git a/src/installer/tests/Microsoft.NET.HostModel.Tests/AppHost.Bundle.Tests/HammerServiceTest.cs b/src/installer/tests/Microsoft.NET.HostModel.Tests/AppHost.Bundle.Tests/HammerServiceTest.cs
index 96c0c7c07baf08..d173883559f7df 100644
--- a/src/installer/tests/Microsoft.NET.HostModel.Tests/AppHost.Bundle.Tests/HammerServiceTest.cs
+++ b/src/installer/tests/Microsoft.NET.HostModel.Tests/AppHost.Bundle.Tests/HammerServiceTest.cs
@@ -21,16 +21,10 @@ public HammerServiceTest(SharedTestState fixture)
         }
 
         [Fact]
+        [SkipOnPlatform(TestPlatforms.Windows, "On Windows, the hammer servicing location is %ProgramFiles%\\coreservicing. Since writing to this location requires administrative privilege, we do not run the test on Windows.")]
         private void SingleFile_Apps_Are_Serviced()
         {
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
-            {
-                // On Windows, the hammer servicing location is %ProgramFiles%\coreservicing.
-                // Since writing to this location requires administrative privilege, we do not run the test on Windows.
-                // On Unix systems, the servicing location is obtained from the environment variable $CORE_SERVICING.
-
-                return;
-            }
+            // On Unix systems, the servicing location is obtained from the environment variable $CORE_SERVICING.
 
             var fixture = sharedTestState.TestFixture.Copy();
             var servicer = sharedTestState.ServiceFixture.Copy();
diff --git a/src/installer/tests/Microsoft.NET.HostModel.Tests/Microsoft.NET.HostModel.AppHost.Tests/AppHostUpdateTests.cs b/src/installer/tests/Microsoft.NET.HostModel.Tests/Microsoft.NET.HostModel.AppHost.Tests/AppHostUpdateTests.cs
index 5fa06a528fc05d..fc0aedbdfbfd7d 100644
--- a/src/installer/tests/Microsoft.NET.HostModel.Tests/Microsoft.NET.HostModel.AppHost.Tests/AppHostUpdateTests.cs
+++ b/src/installer/tests/Microsoft.NET.HostModel.Tests/Microsoft.NET.HostModel.AppHost.Tests/AppHostUpdateTests.cs
@@ -291,7 +291,7 @@ private static class CoreFxFileStatusProvider
 
             static CoreFxFileStatusProvider()
             {
-                if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+                if (!OperatingSystem.IsWindows())
                 {
                     try
                     {
diff --git a/src/installer/tests/Microsoft.NET.HostModel.Tests/Microsoft.NET.HostModel.AppHost.Tests/AppHostUsedWithSymbolicLinks.cs b/src/installer/tests/Microsoft.NET.HostModel.Tests/Microsoft.NET.HostModel.AppHost.Tests/AppHostUsedWithSymbolicLinks.cs
index 991eff791deeef..e00441d92e0cf1 100644
--- a/src/installer/tests/Microsoft.NET.HostModel.Tests/Microsoft.NET.HostModel.AppHost.Tests/AppHostUsedWithSymbolicLinks.cs
+++ b/src/installer/tests/Microsoft.NET.HostModel.Tests/Microsoft.NET.HostModel.AppHost.Tests/AppHostUsedWithSymbolicLinks.cs
@@ -22,14 +22,11 @@ public AppHostUsedWithSymbolicLinks(AppHostUsedWithSymbolicLinks.SharedTestState
         }
 
         [Theory]
+        [SkipOnPlatform(TestPlatforms.Windows, "Creating symbolic links requires administrative privilege on Windows, so skip test.")]
         [InlineData ("a/b/SymlinkToApphost")]
         [InlineData ("a/SymlinkToApphost")]
         public void Run_apphost_behind_symlink(string symlinkRelativePath)
         {
-            // Creating symbolic links requires administrative privilege on Windows, so skip test.
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
-                return;
-
             var fixture = sharedTestState.StandaloneAppFixture_Published
                 .Copy();
 
@@ -48,16 +45,13 @@ public void Run_apphost_behind_symlink(string symlinkRelativePath)
         }
 
         [Theory]
+        [SkipOnPlatform(TestPlatforms.Windows, "Creating symbolic links requires administrative privilege on Windows, so skip test.")]
         [InlineData ("a/b/FirstSymlink", "c/d/SecondSymlink")]
         [InlineData ("a/b/FirstSymlink", "c/SecondSymlink")]
         [InlineData ("a/FirstSymlink", "c/d/SecondSymlink")]
         [InlineData ("a/FirstSymlink", "c/SecondSymlink")]
         public void Run_apphost_behind_transitive_symlinks(string firstSymlinkRelativePath, string secondSymlinkRelativePath)
         {
-            // Creating symbolic links requires administrative privilege on Windows, so skip test.
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
-                return;
-
             var fixture = sharedTestState.StandaloneAppFixture_Published
                 .Copy();
 
@@ -87,12 +81,9 @@ public void Run_apphost_behind_transitive_symlinks(string firstSymlinkRelativePa
         //[InlineData("a/SymlinkToFrameworkDependentApp")]
         [Fact(Skip = "Currently failing in OSX with \"No such file or directory\" when running Command.Create. " +
             "CI failing to use stat on symbolic links on Linux (permission denied).")]
+        [SkipOnPlatform(TestPlatforms.Windows, "Creating symbolic links requires administrative privilege on Windows, so skip test.")]
         public void Run_framework_dependent_app_behind_symlink(/*string symlinkRelativePath*/)
         {
-            // Creating symbolic links requires administrative privilege on Windows, so skip test.
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
-                return;
-
             var symlinkRelativePath = string.Empty;
 
             var fixture = sharedTestState.FrameworkDependentAppFixture_Published
@@ -116,12 +107,9 @@ public void Run_framework_dependent_app_behind_symlink(/*string symlinkRelativeP
 
         [Fact(Skip = "Currently failing in OSX with \"No such file or directory\" when running Command.Create. " +
                      "CI failing to use stat on symbolic links on Linux (permission denied).")]
+        [SkipOnPlatform(TestPlatforms.Windows, "Creating symbolic links requires administrative privilege on Windows, so skip test.")]
         public void Run_framework_dependent_app_with_runtime_behind_symlink()
         {
-            // Creating symbolic links requires administrative privilege on Windows, so skip test.
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
-                return;
-
             var fixture = sharedTestState.FrameworkDependentAppFixture_Published
                 .Copy();
 
@@ -141,12 +129,9 @@ public void Run_framework_dependent_app_with_runtime_behind_symlink()
         }
 
         [Fact]
+        [SkipOnPlatform(TestPlatforms.Windows, "Creating symbolic links requires administrative privilege on Windows, so skip test.")]
         public void Put_app_directory_behind_symlink()
         {
-            // Creating symbolic links requires administrative privilege on Windows, so skip test.
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
-                return;
-
             var fixture = sharedTestState.StandaloneAppFixture_Published
                 .Copy();
 
@@ -165,12 +150,9 @@ public void Put_app_directory_behind_symlink()
         }
 
         [Fact]
+        [SkipOnPlatform(TestPlatforms.Windows, "Creating symbolic links requires administrative privilege on Windows, so skip test.")]
         public void Put_dotnet_behind_symlink()
         {
-            // Creating symbolic links requires administrative privilege on Windows, so skip test.
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
-                return;
-
             var fixture = sharedTestState.StandaloneAppFixture_Published
                 .Copy();
 
@@ -189,12 +171,9 @@ public void Put_dotnet_behind_symlink()
         }
 
         [Fact]
+        [SkipOnPlatform(TestPlatforms.Windows, "Creating symbolic links requires administrative privilege on Windows, so skip test.")]
         public void Put_app_directory_behind_symlink_and_use_dotnet()
         {
-            // Creating symbolic links requires administrative privilege on Windows, so skip test.
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
-                return;
-
             var fixture = sharedTestState.StandaloneAppFixture_Published
                 .Copy();
 
@@ -213,12 +192,9 @@ public void Put_app_directory_behind_symlink_and_use_dotnet()
         }
 
         [Fact]
+        [SkipOnPlatform(TestPlatforms.Windows, "Creating symbolic links requires administrative privilege on Windows, so skip test.")]
         public void Put_app_directory_behind_symlink_and_use_dotnet_run()
         {
-            // Creating symbolic links requires administrative privilege on Windows, so skip test.
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
-                return;
-
             var fixture = sharedTestState.StandaloneAppFixture_Published
                 .Copy();
 
@@ -238,14 +214,10 @@ public void Put_app_directory_behind_symlink_and_use_dotnet_run()
         }
 
         [Fact]
+        // If enabled, this tests will need to set the console code page to output unicode characters: Command.Create("chcp 65001").Execute();
+        [SkipOnPlatform(TestPlatforms.Windows, "Creating symbolic links requires administrative privilege on Windows, so skip test.")]
         public void Put_satellite_assembly_behind_symlink()
         {
-            // Creating symbolic links requires administrative privilege on Windows, so skip test.
-            // If enabled, this tests will need to set the console code page to output unicode characters:
-            // Command.Create("chcp 65001").Execute();
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
-                return;
-
             var fixture = sharedTestState.StandaloneAppFixture_Localized
                 .Copy();
 
diff --git a/src/installer/tests/Microsoft.NET.HostModel.Tests/Microsoft.NET.HostModel.Bundle.Tests/BundlerConsistencyTests.cs b/src/installer/tests/Microsoft.NET.HostModel.Tests/Microsoft.NET.HostModel.Bundle.Tests/BundlerConsistencyTests.cs
index d8aa3eb1edfb81..75d9e44e961ccd 100644
--- a/src/installer/tests/Microsoft.NET.HostModel.Tests/Microsoft.NET.HostModel.Bundle.Tests/BundlerConsistencyTests.cs
+++ b/src/installer/tests/Microsoft.NET.HostModel.Tests/Microsoft.NET.HostModel.Bundle.Tests/BundlerConsistencyTests.cs
@@ -187,7 +187,7 @@ public void TestBaseNameComputation()
             // work correctly in the presence of "."s in the hostName.
             var originalBaseName = "StandaloneApp";
             var newBaseName = "Stand.Alone.App";
-            var exe = RuntimeInformation.IsOSPlatform(OSPlatform.Windows) ? ".exe" : string.Empty;
+            var exe = OperatingSystem.IsWindows() ? ".exe" : string.Empty;
 
             void rename(string extension)
             {
diff --git a/src/installer/tests/TestUtils/Command.cs b/src/installer/tests/TestUtils/Command.cs
index 1e300d6077ba4e..3c3e5607dde90a 100644
--- a/src/installer/tests/TestUtils/Command.cs
+++ b/src/installer/tests/TestUtils/Command.cs
@@ -29,7 +29,7 @@ public class Command
         public Process Process { get; }
 
         // Priority order of runnable suffixes to look for and run
-        private static readonly string[] RunnableSuffixes = RuntimeInformation.IsOSPlatform(OSPlatform.Windows)
+        private static readonly string[] RunnableSuffixes = OperatingSystem.IsWindows()
                                                          ? new string[] { ".exe", ".cmd", ".bat" }
                                                          : new string[] { string.Empty };
 
@@ -102,7 +102,7 @@ private static void ResolveExecutablePath(ref string executable, ref string args
 
         private static bool ShouldUseCmd(string executable)
         {
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            if (OperatingSystem.IsWindows())
             {
                 var extension = Path.GetExtension(executable);
                 if (!string.IsNullOrEmpty(extension))
@@ -249,7 +249,7 @@ public Command WorkingDirectory(string projectDirectory)
         public Command WithUserProfile(string userprofile)
         {
             string userDir;
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            if (OperatingSystem.IsWindows())
             {
                 userDir = "USERPROFILE";
             }
diff --git a/src/installer/tests/TestUtils/SymbolicLinking.cs b/src/installer/tests/TestUtils/SymbolicLinking.cs
index 81ed64bf115d71..bf7dbf45df0c8a 100644
--- a/src/installer/tests/TestUtils/SymbolicLinking.cs
+++ b/src/installer/tests/TestUtils/SymbolicLinking.cs
@@ -33,7 +33,7 @@ public void Dispose()
         private static bool MakeSymbolicLink(string symbolicLinkName, string targetFileName, out string errorMessage)
         {
             errorMessage = string.Empty;
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            if (OperatingSystem.IsWindows())
             {
                 if (!CreateSymbolicLink(symbolicLinkName, targetFileName, SymbolicLinkFlag.IsFile))
                 {
diff --git a/src/libraries/Common/src/System/Security/Cryptography/DSACng.cs b/src/libraries/Common/src/System/Security/Cryptography/DSACng.cs
index 508fd0c79f3a27..a89f2706a23d43 100644
--- a/src/libraries/Common/src/System/Security/Cryptography/DSACng.cs
+++ b/src/libraries/Common/src/System/Security/Cryptography/DSACng.cs
@@ -73,7 +73,7 @@ private void ForceSetKeySize(int newKeySize)
 
             private static bool Supports2048KeySize()
             {
-                Debug.Assert(RuntimeInformation.IsOSPlatform(OSPlatform.Windows));
+                Debug.Assert(OperatingSystem.IsWindows());
                 Version version = Environment.OSVersion.Version;
                 bool isAtLeastWindows8 = version.Major > 6 || (version.Major == 6 && version.Minor >= 2);
                 return isAtLeastWindows8;
diff --git a/src/libraries/Common/tests/System/Net/Capability.Sockets.cs b/src/libraries/Common/tests/System/Net/Capability.Sockets.cs
index efef8f64046e80..a28c982032ad9e 100644
--- a/src/libraries/Common/tests/System/Net/Capability.Sockets.cs
+++ b/src/libraries/Common/tests/System/Net/Capability.Sockets.cs
@@ -25,7 +25,7 @@ private struct RTL_OSVERSIONINFOW
 
         public static bool? SocketsReuseUnicastPortSupport()
         {
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            if (OperatingSystem.IsWindows())
             {
                 RTL_OSVERSIONINFOW v = default(RTL_OSVERSIONINFOW);
                 v.dwOSVersionInfoSize = (uint)Marshal.SizeOf<RTL_OSVERSIONINFOW>();
diff --git a/src/libraries/Common/tests/System/Security/Cryptography/AlgorithmImplementations/EC/EccTestBase.cs b/src/libraries/Common/tests/System/Security/Cryptography/AlgorithmImplementations/EC/EccTestBase.cs
index 16a8cefd84106a..2f347469e12cb9 100644
--- a/src/libraries/Common/tests/System/Security/Cryptography/AlgorithmImplementations/EC/EccTestBase.cs
+++ b/src/libraries/Common/tests/System/Security/Cryptography/AlgorithmImplementations/EC/EccTestBase.cs
@@ -204,7 +204,7 @@ internal static void CompareCurve(in ECCurve c1, in ECCurve c2)
             {
                 Assert.True(c2.IsNamed);
 
-                if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows) ||
+                if (OperatingSystem.IsWindows() ||
                     string.IsNullOrEmpty(c1.Oid.Value))
                 {
                     Assert.Equal(c1.Oid.FriendlyName, c2.Oid.FriendlyName);
diff --git a/src/libraries/Common/tests/System/Security/Cryptography/AlgorithmImplementations/ECDiffieHellman/ECDiffieHellmanTests.NistValidation.cs b/src/libraries/Common/tests/System/Security/Cryptography/AlgorithmImplementations/ECDiffieHellman/ECDiffieHellmanTests.NistValidation.cs
index 46b2187f7fa8d1..7e5d408c4c9aea 100644
--- a/src/libraries/Common/tests/System/Security/Cryptography/AlgorithmImplementations/ECDiffieHellman/ECDiffieHellmanTests.NistValidation.cs
+++ b/src/libraries/Common/tests/System/Security/Cryptography/AlgorithmImplementations/ECDiffieHellman/ECDiffieHellmanTests.NistValidation.cs
@@ -185,7 +185,7 @@ private static void Verify(
                             // represent the same curve.
                             //
                             // secp256r1 and secp521r1 both succeed this block, secp384r1 fails.
-                            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+                            if (OperatingSystem.IsWindows())
                             {
                                 throw;
                             }
diff --git a/src/libraries/System.Net.Http/tests/StressTests/HttpStress/StressServer.cs b/src/libraries/System.Net.Http/tests/StressTests/HttpStress/StressServer.cs
index 1d5dab37ecba37..6012965d2a5097 100644
--- a/src/libraries/System.Net.Http/tests/StressTests/HttpStress/StressServer.cs
+++ b/src/libraries/System.Net.Http/tests/StressTests/HttpStress/StressServer.cs
@@ -102,7 +102,7 @@ void ConfigureListenOptions(ListenOptions listenOptions)
                                 certReq.CertificateExtensions.Add(new X509EnhancedKeyUsageExtension(new OidCollection { new Oid("1.3.6.1.5.5.7.3.1") }, false));
                                 certReq.CertificateExtensions.Add(new X509KeyUsageExtension(X509KeyUsageFlags.DigitalSignature, false));
                                 X509Certificate2 cert = certReq.CreateSelfSigned(DateTimeOffset.UtcNow.AddMonths(-1), DateTimeOffset.UtcNow.AddMonths(1));
-                                if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+                                if (OperatingSystem.IsWindows())
                                 {
                                     cert = new X509Certificate2(cert.Export(X509ContentType.Pfx));
                                 }
diff --git a/src/libraries/System.Net.Security/tests/StressTests/SslStress/SslServerBase.cs b/src/libraries/System.Net.Security/tests/StressTests/SslStress/SslServerBase.cs
index 56ba32e7c0363c..f43cfb4d5b8588 100644
--- a/src/libraries/System.Net.Security/tests/StressTests/SslStress/SslServerBase.cs
+++ b/src/libraries/System.Net.Security/tests/StressTests/SslStress/SslServerBase.cs
@@ -158,7 +158,7 @@ protected virtual X509Certificate2 CreateSelfSignedCertificate()
             certReq.CertificateExtensions.Add(new X509EnhancedKeyUsageExtension(new OidCollection { new Oid("1.3.6.1.5.5.7.3.1") }, false));
             certReq.CertificateExtensions.Add(new X509KeyUsageExtension(X509KeyUsageFlags.DigitalSignature, false));
             X509Certificate2 cert = certReq.CreateSelfSigned(DateTimeOffset.UtcNow.AddMonths(-1), DateTimeOffset.UtcNow.AddMonths(1));
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            if (OperatingSystem.IsWindows())
             {
                 cert = new X509Certificate2(cert.Export(X509ContentType.Pfx));
             }
diff --git a/src/libraries/System.Net.Sockets/tests/FunctionalTests/CreateSocketTests.cs b/src/libraries/System.Net.Sockets/tests/FunctionalTests/CreateSocketTests.cs
index 7252fb847cdad7..334280938e0a0f 100644
--- a/src/libraries/System.Net.Sockets/tests/FunctionalTests/CreateSocketTests.cs
+++ b/src/libraries/System.Net.Sockets/tests/FunctionalTests/CreateSocketTests.cs
@@ -312,8 +312,8 @@ public void Ctor_SafeHandle_BasicPropertiesPropagate_Success(AddressFamily addre
             if (copy.IsBound)
             {
                 // On Unix, we may successfully obtain an (empty) local end point, even though Bind wasn't called.
-                Debug.Assert(!RuntimeInformation.IsOSPlatform(OSPlatform.Windows));
-                if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux)) // OSX gets some strange results in some cases, e.g. "@\0\0\0\0\0\0\0\0\0\0\0\0\0" for a UDS
+                Debug.Assert(!OperatingSystem.IsWindows());
+                if (OperatingSystem.IsLinux()) // OSX gets some strange results in some cases, e.g. "@\0\0\0\0\0\0\0\0\0\0\0\0\0" for a UDS
                 {
                     switch (addressFamily)
                     {
diff --git a/src/libraries/System.Net.Sockets/tests/FunctionalTests/DualModeSocketTest.cs b/src/libraries/System.Net.Sockets/tests/FunctionalTests/DualModeSocketTest.cs
index 600ae16628985e..eb229d9d37e3f4 100644
--- a/src/libraries/System.Net.Sockets/tests/FunctionalTests/DualModeSocketTest.cs
+++ b/src/libraries/System.Net.Sockets/tests/FunctionalTests/DualModeSocketTest.cs
@@ -154,7 +154,7 @@ private void DualModeConnect_IPAddressToHost_Fails_Helper(IPAddress connectTo, I
             Assert.ThrowsAny<SocketException>(() =>
             {
                 DualModeConnect_IPAddressToHost_Helper(connectTo, listenOn, false);
-                if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+                if (!OperatingSystem.IsWindows())
                 {
                     // On Unix, socket assignment is random (not incremental) and there is a small chance the
                     // listening socket was created in another test currently running. Try the test one more time.
@@ -245,7 +245,7 @@ private void DualModeConnect_IPEndPointToHost_Fails_Helper(IPAddress connectTo,
             Assert.ThrowsAny<SocketException>(() =>
             {
                 DualModeConnect_IPEndPointToHost_Helper(connectTo, listenOn, false);
-                if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+                if (!OperatingSystem.IsWindows())
                 {
                     // On Unix, socket assignment is random (not incremental) and there is a small chance the
                     // listening socket was created in another test currently running. Try the test one more time.
@@ -384,7 +384,7 @@ private async Task DualModeBeginConnect_IPAddressToHost_Fails_Helper(IPAddress c
             SocketException e = await Assert.ThrowsAnyAsync<SocketException>(async () =>
             {
                 await DualModeBeginConnect_IPAddressToHost_Helper(connectTo, listenOn, false);
-                if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+                if (!OperatingSystem.IsWindows())
                 {
                     // On Unix, socket assignment is random (not incremental) and there is a small chance the
                     // listening socket was created in another test currently running. Try the test one more time.
@@ -565,7 +565,7 @@ private void DualModeConnectAsync_IPEndPointToHost_Fails_Helper(IPAddress connec
             Assert.ThrowsAny<SocketException>(() =>
             {
                 DualModeConnectAsync_IPEndPointToHost_Helper(connectTo, listenOn, false);
-                if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+                if (!OperatingSystem.IsWindows())
                 {
                     // On Unix, socket assignment is random (not incremental) and there is a small chance the
                     // listening socket was created in another test currently running. Try the test one more time.
@@ -1239,11 +1239,11 @@ public void Socket_SendToAsyncV4IPEndPointToV4Host_Throws()
                 bool async = socket.SendToAsync(args);
                 Assert.False(async);
 
-                if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+                if (OperatingSystem.IsWindows())
                 {
                     Assert.Equal(SocketError.Fault, args.SocketError);
                 }
-                else if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
+                else if (OperatingSystem.IsLinux())
                 {
                     // NOTE: on Linux, this API returns ENETUNREACH instead of EFAULT: this platform
                     //       checks the family of the provided socket address before checking its size
@@ -2015,7 +2015,7 @@ private void ReceiveMessageFrom_Helper(IPAddress listenOn, IPAddress connectTo,
 
                 serverSocket.ReceiveTimeout = TestSettings.FailingTestTimeout;
 
-                if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+                if (OperatingSystem.IsWindows())
                 {
                     Assert.Throws<SocketException>(() =>
                     {
@@ -2469,11 +2469,11 @@ private static bool GetLocalhostIsBothIPv4AndIPv6()
 
         protected static void AssertDualModeEnabled(Socket socket, IPAddress listenOn)
         {
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            if (OperatingSystem.IsWindows())
             {
                 Assert.True(socket.DualMode);
             }
-            else if (RuntimeInformation.IsOSPlatform(OSPlatform.FreeBSD))
+            else if (OperatingSystem.IsFreeBSD())
             {
                 // This is not valid check on FreeBSD.
                 // Accepted socket is never DualMode and cannot be changed.
diff --git a/src/libraries/System.Net.Sockets/tests/FunctionalTests/NetworkStreamTest.cs b/src/libraries/System.Net.Sockets/tests/FunctionalTests/NetworkStreamTest.cs
index 05f7f9b8c1d6d2..52022c5da82164 100644
--- a/src/libraries/System.Net.Sockets/tests/FunctionalTests/NetworkStreamTest.cs
+++ b/src/libraries/System.Net.Sockets/tests/FunctionalTests/NetworkStreamTest.cs
@@ -414,7 +414,7 @@ await RunWithConnectedNetworkStreamsAsync(async (stream, _) =>
                 // socket is closed.  On Unix, it's completed as successful once or after
                 // the shutdown is issued, but depending on timing, if it's then closed
                 // before that takes effect, it may also complete as aborted.
-                bool isWindows = RuntimeInformation.IsOSPlatform(OSPlatform.Windows);
+                bool isWindows = OperatingSystem.IsWindows();
                 Assert.True(
                     (isWindows && e is IOException) ||
                     (!isWindows && (e == null || e is IOException)),
diff --git a/src/libraries/System.Net.Sockets/tests/FunctionalTests/SocketOptionNameTest.cs b/src/libraries/System.Net.Sockets/tests/FunctionalTests/SocketOptionNameTest.cs
index a504f3957dd3b2..eccff0d22d6302 100644
--- a/src/libraries/System.Net.Sockets/tests/FunctionalTests/SocketOptionNameTest.cs
+++ b/src/libraries/System.Net.Sockets/tests/FunctionalTests/SocketOptionNameTest.cs
@@ -263,7 +263,7 @@ public void FailedConnect_GetSocketOption_SocketOptionNameError(bool simpleGet)
                 Assert.Equal((int)SocketError.ConnectionRefused, errorCode);
 
                 // Then get it again
-                if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+                if (OperatingSystem.IsWindows())
                 {
                     // The Windows implementation doesn't clear the error code after retrieved.
                     // https://github.com/dotnet/runtime/issues/17260
@@ -431,14 +431,14 @@ public unsafe void ReuseAddressUdp()
             // that allow binding the same address.
             int SOL_SOCKET = -1;
             int option = -1;
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
+            if (OperatingSystem.IsLinux())
             {
                 // Linux: use SO_REUSEADDR to allow binding the same address.
                 SOL_SOCKET = 1;
                 const int SO_REUSEADDR = 2;
                 option = SO_REUSEADDR;
             }
-            else if (RuntimeInformation.IsOSPlatform(OSPlatform.OSX))
+            else if (OperatingSystem.IsMacOS())
             {
                 // BSD: use SO_REUSEPORT to allow binding the same address.
                 SOL_SOCKET = 0xffff;
@@ -514,13 +514,13 @@ public void GetSetRawSocketOption_Roundtrips(AddressFamily family)
             int SOL_SOCKET;
             int SO_RCVBUF;
 
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows) ||
-                RuntimeInformation.IsOSPlatform(OSPlatform.OSX))
+            if (OperatingSystem.IsWindows() ||
+                OperatingSystem.IsMacOS())
             {
                 SOL_SOCKET = 0xffff;
                 SO_RCVBUF = 0x1002;
             }
-            else if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
+            else if (OperatingSystem.IsLinux())
             {
                 SOL_SOCKET = 1;
                 SO_RCVBUF = 8;
@@ -534,7 +534,7 @@ public void GetSetRawSocketOption_Roundtrips(AddressFamily family)
             {
                 const int SetSize = 8192;
                 int ExpectedGetSize =
-                    RuntimeInformation.IsOSPlatform(OSPlatform.Linux) ? SetSize * 2 : // Linux kernel documented to double the size
+                    OperatingSystem.IsLinux() ? SetSize * 2 : // Linux kernel documented to double the size
                     SetSize;
 
                 socket.SetRawSocketOption(SOL_SOCKET, SO_RCVBUF, BitConverter.GetBytes(SetSize));
diff --git a/src/libraries/System.Net.Sockets/tests/FunctionalTests/UnixDomainSocketTest.cs b/src/libraries/System.Net.Sockets/tests/FunctionalTests/UnixDomainSocketTest.cs
index 35486516aec121..da2d4d67ba39af 100644
--- a/src/libraries/System.Net.Sockets/tests/FunctionalTests/UnixDomainSocketTest.cs
+++ b/src/libraries/System.Net.Sockets/tests/FunctionalTests/UnixDomainSocketTest.cs
@@ -108,7 +108,7 @@ public async Task Socket_ConnectAsyncUnixDomainSocketEndPoint_NotServer()
                     }
 
                     Assert.Equal(
-                        RuntimeInformation.IsOSPlatform(OSPlatform.Windows) ? SocketError.ConnectionRefused : SocketError.AddressNotAvailable,
+                        OperatingSystem.IsWindows() ? SocketError.ConnectionRefused : SocketError.AddressNotAvailable,
                         args.SocketError);
                 }
             }
@@ -421,7 +421,7 @@ public void UnixDomainSocketEndPoint_RemoteEndPointEqualsBindAddress(bool abstra
             if (abstractAddress)
             {
                 // abstract socket addresses are a Linux feature.
-                if (!RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
+                if (!OperatingSystem.IsLinux())
                 {
                     return;
                 }
@@ -518,7 +518,7 @@ private static bool PlatformSupportsUnixDomainSockets
         {
             get
             {
-                if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+                if (OperatingSystem.IsWindows())
                 {
                     try
                     {
diff --git a/src/libraries/System.Security.Cryptography.X509Certificates/tests/DynamicChainTests.cs b/src/libraries/System.Security.Cryptography.X509Certificates/tests/DynamicChainTests.cs
index 1b224441a0b092..2fe04218e09d08 100644
--- a/src/libraries/System.Security.Cryptography.X509Certificates/tests/DynamicChainTests.cs
+++ b/src/libraries/System.Security.Cryptography.X509Certificates/tests/DynamicChainTests.cs
@@ -631,7 +631,7 @@ public static void MismatchKeyIdentifiers()
                 chain.ChainPolicy.CustomTrustStore.Add(rootCert);
                 chain.ChainPolicy.ExtraStore.Add(intermediateCert);
 
-                if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
+                if (OperatingSystem.IsLinux())
                 {
                     Assert.False(chain.Build(endEntityCert), "chain.Build");
                     Assert.Equal(X509ChainStatusFlags.PartialChain, chain.AllStatusFlags());
diff --git a/src/tests/Common/CoreCLRTestLibrary/Utilities.cs b/src/tests/Common/CoreCLRTestLibrary/Utilities.cs
index ffd9f00da0bda5..bd1eb1be37de73 100644
--- a/src/tests/Common/CoreCLRTestLibrary/Utilities.cs
+++ b/src/tests/Common/CoreCLRTestLibrary/Utilities.cs
@@ -62,9 +62,9 @@ public static bool Verbose
         public static bool IsArm => (RuntimeInformation.ProcessArchitecture == Architecture.Arm);
         public static bool IsArm64 => (RuntimeInformation.ProcessArchitecture == Architecture.Arm64);
 
-        public static bool IsWindows => RuntimeInformation.IsOSPlatform(OSPlatform.Windows);
-        public static bool IsLinux => RuntimeInformation.IsOSPlatform(OSPlatform.Linux);
-        public static bool IsMacOSX => RuntimeInformation.IsOSPlatform(OSPlatform.OSX);
+        public static bool IsWindows => OperatingSystem.IsWindows();
+        public static bool IsLinux => OperatingSystem.IsLinux();
+        public static bool IsMacOSX => OperatingSystem.IsMacOS();
         public static bool IsWindows7 => IsWindows && Environment.OSVersion.Version.Major == 6 && Environment.OSVersion.Version.Minor == 1;
         public static bool IsWindowsNanoServer => (!IsWindowsIoTCore && GetInstallationType().Equals("Nano Server", StringComparison.OrdinalIgnoreCase));
 
diff --git a/src/tests/Common/Coreclr.TestWrapper/CoreclrTestWrapperLib.cs b/src/tests/Common/Coreclr.TestWrapper/CoreclrTestWrapperLib.cs
index 22c606728ac701..074eb1a2df3c99 100644
--- a/src/tests/Common/Coreclr.TestWrapper/CoreclrTestWrapperLib.cs
+++ b/src/tests/Common/Coreclr.TestWrapper/CoreclrTestWrapperLib.cs
@@ -78,15 +78,15 @@ internal static class ProcessExtensions
         public unsafe static IEnumerable<Process> GetChildren(this Process process)
         {
             var children = new List<Process>();
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            if (OperatingSystem.IsWindows())
             {
                 return Windows_GetChildren(process);
             }
-            else if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
+            else if (OperatingSystem.IsLinux())
             {
                 return Linux_GetChildren(process);
             }
-            else if (RuntimeInformation.IsOSPlatform(OSPlatform.OSX))
+            else if (OperatingSystem.IsMacOS())
             {
                 return MacOS_GetChildren(process);
             }
@@ -210,12 +210,12 @@ static bool CollectCrashDump(Process process, string path)
             string arguments = $"--name \"{path}\" {process.Id} --withheap";
             Process createdump = new Process();
 
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            if (OperatingSystem.IsWindows())
             {
                 createdump.StartInfo.FileName = createdumpPath + ".exe";
                 createdump.StartInfo.Arguments = arguments;
             }
-            else if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux) || RuntimeInformation.IsOSPlatform(OSPlatform.OSX))
+            else if (OperatingSystem.IsLinux() || OperatingSystem.IsMacOS())
             {
                 createdump.StartInfo.FileName = "sudo";
                 createdump.StartInfo.Arguments = $"{createdumpPath} " + arguments;
@@ -305,7 +305,7 @@ public int RunTest(string executable, string outputFile, string errorFile, strin
             using (Process process = new Process())
             {
                 // Windows can run the executable implicitly
-                if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+                if (OperatingSystem.IsWindows())
                 {
                     process.StartInfo.FileName = executable;
                 }
diff --git a/src/tests/CoreMangLib/system/runtime/interopservices/marshal/marshalsizeof1.cs b/src/tests/CoreMangLib/system/runtime/interopservices/marshal/marshalsizeof1.cs
index b600f3d66de27c..5cd2fd3a5aeda6 100644
--- a/src/tests/CoreMangLib/system/runtime/interopservices/marshal/marshalsizeof1.cs
+++ b/src/tests/CoreMangLib/system/runtime/interopservices/marshal/marshalsizeof1.cs
@@ -226,7 +226,7 @@ public bool PosTest4()
             obj.TestDouble = TestLibrary.Generator.GetDouble(-55);
             int expectedSize;
 
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows) || (RuntimeInformation.ProcessArchitecture != Architecture.X86))
+            if (OperatingSystem.IsWindows() || (RuntimeInformation.ProcessArchitecture != Architecture.X86))
             {
                 expectedSize = 16; // sizeof(double) + sizeof(int) + padding
             }
diff --git a/src/tests/CoreMangLib/system/runtime/interopservices/marshal/marshalsizeof2.cs b/src/tests/CoreMangLib/system/runtime/interopservices/marshal/marshalsizeof2.cs
index 59bc6dbe9fb539..3b3f9c8ac35d80 100644
--- a/src/tests/CoreMangLib/system/runtime/interopservices/marshal/marshalsizeof2.cs
+++ b/src/tests/CoreMangLib/system/runtime/interopservices/marshal/marshalsizeof2.cs
@@ -211,7 +211,7 @@ public bool PosTest4()
             Type obj = typeof(TestMultiMemberStruct1);
             int expectedSize;
 
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows) || (RuntimeInformation.ProcessArchitecture != Architecture.X86))
+            if (OperatingSystem.IsWindows() || (RuntimeInformation.ProcessArchitecture != Architecture.X86))
             {
                 expectedSize = 16; // sizeof(double) + sizeof(int) + padding
             }
diff --git a/src/tests/GC/LargeMemory/memcheck.cs b/src/tests/GC/LargeMemory/memcheck.cs
index 793b941fcb4240..5fbda715390228 100644
--- a/src/tests/GC/LargeMemory/memcheck.cs
+++ b/src/tests/GC/LargeMemory/memcheck.cs
@@ -37,7 +37,7 @@ public static uint LimitByAvailableMemMB(uint sizeMB, uint defaultMB = 300)
     }
 
     private static uint? TryGetPhysicalMemMB() =>
-        RuntimeInformation.IsOSPlatform(OSPlatform.Windows)
+        OperatingSystem.IsWindows()
             ? TryGetPhysicalMemMBWindows()
             : TryGetPhysicalMemMBNonWindows();
 
diff --git a/src/tests/Interop/COM/Reflection/Reflection.cs b/src/tests/Interop/COM/Reflection/Reflection.cs
index cccb9625937caa..d850e9c5b61375 100644
--- a/src/tests/Interop/COM/Reflection/Reflection.cs
+++ b/src/tests/Interop/COM/Reflection/Reflection.cs
@@ -76,7 +76,7 @@ static bool ActivateCOMType()
             var contextMenu = (NETServer.ContextMenu)Activator.CreateInstance(typeof(NETServer.ContextMenu));
 
             // Non-Windows should throw PlatformNotSupportedException
-            if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            if (!OperatingSystem.IsWindows())
             {
                 return false;
             }
@@ -89,11 +89,11 @@ static bool ActivateCOMType()
 
             return true;
         }
-        catch (PlatformNotSupportedException) when (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+        catch (PlatformNotSupportedException) when (!OperatingSystem.IsWindows())
         {
             return true;
         }
-        catch (COMException) when (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+        catch (COMException) when (OperatingSystem.IsWindows())
         {
             return true;
         }
diff --git a/src/tests/Interop/DllImportAttribute/DllImportPath/DllImportPathTest.cs b/src/tests/Interop/DllImportAttribute/DllImportPath/DllImportPathTest.cs
index 8a53250d4442e3..c83295d89292a4 100644
--- a/src/tests/Interop/DllImportAttribute/DllImportPath/DllImportPathTest.cs
+++ b/src/tests/Interop/DllImportAttribute/DllImportPath/DllImportPathTest.cs
@@ -66,7 +66,7 @@ static void TestNativeLibraryProbingOnLocalPath()
 
         GetZero_Local1();
 
-        if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+        if (OperatingSystem.IsWindows())
         {
             GetZero_Local2();
 
@@ -80,7 +80,7 @@ static void TestNativeLibraryProbingOnRelativePath()
     {
         string strManaged = "Managed";
         string native = " Native";
-        bool isWindows = RuntimeInformation.IsOSPlatform(OSPlatform.Windows);
+        bool isWindows = OperatingSystem.IsWindows();
 
         if (!isWindows) // We need to ensure that the subdirectory exists for off-Windows.
         {        
@@ -98,7 +98,7 @@ static void TestNativeLibraryProbingOnRelativePath()
             GetZero_Relative1Unix();
         }
         
-        if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+        if (OperatingSystem.IsWindows())
         {
             GetZero_Relative2();
         }
@@ -112,7 +112,7 @@ static void TestNativeLibraryProbingOnRelativePath()
             GetZero_Relative3Unix();
         }
 
-        if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+        if (OperatingSystem.IsWindows())
         {
             GetZero_Relative4();
         }
@@ -174,12 +174,12 @@ public static int Main(string[] args)
         {
             TestNativeLibraryProbingOnLocalPath();
             TestNativeLibraryProbingOnRelativePath();
-            if (!RuntimeInformation.IsOSPlatform(OSPlatform.OSX)) // This test fails due to a bug in OSX 10.12 combined with the weird way that HFS+ handles unicode file names
+            if (!OperatingSystem.IsMacOS()) // This test fails due to a bug in OSX 10.12 combined with the weird way that HFS+ handles unicode file names
             {
                 TestNativeLibraryProbingUnicode();
             }
             TestNativeLibraryProbingOnPathEnv();
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            if (OperatingSystem.IsWindows())
             {
                 TestNativeExeProbing();
             }
diff --git a/src/tests/Interop/DllImportAttribute/ExactSpelling/ExactSpellingTest.cs b/src/tests/Interop/DllImportAttribute/ExactSpelling/ExactSpellingTest.cs
index 3db1b9ceeaf96c..929f2b7518765f 100644
--- a/src/tests/Interop/DllImportAttribute/ExactSpelling/ExactSpellingTest.cs
+++ b/src/tests/Interop/DllImportAttribute/ExactSpelling/ExactSpellingTest.cs
@@ -130,7 +130,7 @@ public static int Main(string[] args)
         try
         {
             ExactSpellingTrue();
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            if (OperatingSystem.IsWindows())
             {
                 ExactSpellingFalse_Windows();
             }
diff --git a/src/tests/Interop/NativeLibrary/NativeLibraryToLoad/NativeLibraryToLoad.cs b/src/tests/Interop/NativeLibrary/NativeLibraryToLoad/NativeLibraryToLoad.cs
index c9ad4a09845c61..4a61c599961f5a 100644
--- a/src/tests/Interop/NativeLibrary/NativeLibraryToLoad/NativeLibraryToLoad.cs
+++ b/src/tests/Interop/NativeLibrary/NativeLibraryToLoad/NativeLibraryToLoad.cs
@@ -13,13 +13,13 @@ public class NativeLibraryToLoad
 
     public static string GetFileName()
     {
-        if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+        if (OperatingSystem.IsWindows())
             return $"{Name}.dll";
 
-        if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
+        if (OperatingSystem.IsLinux())
             return $"lib{Name}.so";
 
-        if (RuntimeInformation.IsOSPlatform(OSPlatform.OSX))
+        if (OperatingSystem.IsMacOS())
             return $"lib{Name}.dylib";
 
         throw new PlatformNotSupportedException();
diff --git a/src/tests/Interop/PInvoke/Array/MarshalArrayAsField/AsByValArray/AsByValArrayTest.cs b/src/tests/Interop/PInvoke/Array/MarshalArrayAsField/AsByValArray/AsByValArrayTest.cs
index 7649c8e0f0e3a6..036f282ef685f3 100644
--- a/src/tests/Interop/PInvoke/Array/MarshalArrayAsField/AsByValArray/AsByValArrayTest.cs
+++ b/src/tests/Interop/PInvoke/Array/MarshalArrayAsField/AsByValArray/AsByValArrayTest.cs
@@ -851,7 +851,7 @@ static void RunTest1(string report)
         s12.arr = InitArray<string>(ARRAY_SIZE);
         Assert.IsTrue(TakeLPCSTRArraySeqStructByVal(s12, s12.arr.Length),"TakeLPCSTRArraySeqStructByVal");
 
-        if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+        if (OperatingSystem.IsWindows())
         {
             S_BSTRArray_Seq s13 = new S_BSTRArray_Seq();
             s13.arr = InitArray<string>(ARRAY_SIZE);
@@ -939,7 +939,7 @@ static void RunTest2(string report)
         c12.arr = InitArray<string>(ARRAY_SIZE);
         Assert.IsTrue(TakeLPCSTRArraySeqClassByVal(c12, c12.arr.Length));
 
-        if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+        if (OperatingSystem.IsWindows())
         {
             C_BSTRArray_Seq c13 = new C_BSTRArray_Seq();
             c13.arr = InitArray<string>(ARRAY_SIZE);
@@ -1004,7 +1004,7 @@ static void RunTest3(string report)
         Assert.IsTrue(TakeLPCSTRArrayExpStructByVal(s12, s12.arr.Length));
 
 
-        if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+        if (OperatingSystem.IsWindows())
         {
             S_BSTRArray_Exp c13 = new S_BSTRArray_Exp();
             c13.arr = InitArray<string>(ARRAY_SIZE);
@@ -1068,7 +1068,7 @@ static void RunTest4(string report)
         c12.arr = InitArray<string>(ARRAY_SIZE);
         Assert.IsTrue(TakeLPCSTRArrayExpClassByVal(c12, c12.arr.Length));
 
-        if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+        if (OperatingSystem.IsWindows())
         {
             C_BSTRArray_Exp c13 = new C_BSTRArray_Exp();
             c13.arr = InitArray<string>(ARRAY_SIZE);
@@ -1120,7 +1120,7 @@ static void RunTest5(string report)
         C_LPSTRArray_Seq retval11 = S_LPSTRArray_Ret();
         Assert.IsTrue(Equals(InitArray<string>(ARRAY_SIZE), retval11.arr));
 
-        if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+        if (OperatingSystem.IsWindows())
         {
             C_BSTRArray_Seq retval12 = S_BSTRArray_Ret();
             Assert.IsTrue(Equals(InitArray<string>(ARRAY_SIZE), retval12.arr));
@@ -1167,7 +1167,7 @@ static void RunTest6(string report)
         C_LPSTRArray_Exp retval11 = S_LPSTRArray_Ret2();
         Assert.IsTrue(Equals(InitArray<string>(ARRAY_SIZE), retval11.arr));
 
-        if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+        if (OperatingSystem.IsWindows())
         {
             C_BSTRArray_Exp retval12 = S_BSTRArray_Ret2();
             Assert.IsTrue(Equals(InitArray<string>(ARRAY_SIZE), retval12.arr));
@@ -1183,7 +1183,7 @@ static int Main(string[] args)
         {
             RunTest1("RunTest1 : Marshal array as field as ByValArray in sequential struct as parameter.");
             RunTest2("RunTest2 : Marshal array as field as ByValArray in sequential class as parameter.");
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            if (OperatingSystem.IsWindows())
             {
                 RunTest3("RunTest3 : Marshal array as field as ByValArray in explicit struct as parameter.");
             }
diff --git a/src/tests/Interop/PInvoke/Array/MarshalArrayAsField/AsLPArray/AsLPArrayTest.cs b/src/tests/Interop/PInvoke/Array/MarshalArrayAsField/AsLPArray/AsLPArrayTest.cs
index 4fbd6d9658754f..70b9618e57752a 100644
--- a/src/tests/Interop/PInvoke/Array/MarshalArrayAsField/AsLPArray/AsLPArrayTest.cs
+++ b/src/tests/Interop/PInvoke/Array/MarshalArrayAsField/AsLPArray/AsLPArrayTest.cs
@@ -218,7 +218,7 @@ static void RunTest1(string report)
         s12.arr = InitArray<string>(ARRAY_SIZE);
         Assert.Throws<TypeLoadException>(() => TakeLPCSTRArraySeqStructByVal(s12, ARRAY_SIZE), "TakeLPCSTRArraySeqStructByVal");
 
-        if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+        if (OperatingSystem.IsWindows())
         {
             S_BSTRArray_Seq s13 = new S_BSTRArray_Seq();
             s13.arr = InitArray<string>(ARRAY_SIZE);
@@ -281,7 +281,7 @@ static void RunTest2(string report)
         c12.arr = InitArray<string>(ARRAY_SIZE);
         Assert.Throws<TypeLoadException>(() => TakeLPCSTRArraySeqClassByVal(c12, ARRAY_SIZE), "TakeLPCSTRArraySeqClassByVal");
 
-        if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+        if (OperatingSystem.IsWindows())
         {
             C_BSTRArray_Seq c13 = new C_BSTRArray_Seq();
             c13.arr = InitArray<string>(ARRAY_SIZE);
@@ -345,7 +345,7 @@ static void RunTest3(string report)
         s12.arr = InitArray<string>(ARRAY_SIZE);
         Assert.Throws<TypeLoadException>(() => TakeLPCSTRArrayExpStructByVal(s12, ARRAY_SIZE), "TakeLPCSTRArrayExpStructByVal");
 
-        if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+        if (OperatingSystem.IsWindows())
         {
             S_BSTRArray_Exp s13 = new S_BSTRArray_Exp();
             s13.arr = InitArray<string>(ARRAY_SIZE);
@@ -409,7 +409,7 @@ static void RunTest4(string report)
         c12.arr = InitArray<string>(ARRAY_SIZE);
         Assert.Throws<TypeLoadException>(() => TakeLPCSTRArrayExpClassByVal(c12, ARRAY_SIZE), "TakeLPCSTRArrayExpClassByVal");
 
-        if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+        if (OperatingSystem.IsWindows())
         {
             C_BSTRArray_Exp c13 = new C_BSTRArray_Exp();
             c13.arr = InitArray<string>(ARRAY_SIZE);
@@ -427,7 +427,7 @@ static int Main(string[] args)
         {
             RunTest1("RunTest 1 : Marshal Array In Sequential Struct As LPArray. ");
             RunTest2("RunTest 2 : Marshal Array In Sequential Class As LPArray. ");
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            if (OperatingSystem.IsWindows())
             {
                 RunTest3("RunTest 3 : Marshal Array In Explicit Struct As LPArray. "); 
             }
diff --git a/src/tests/Interop/PInvoke/Array/MarshalArrayAsParam/AsDefault/AsDefaultTest.cs b/src/tests/Interop/PInvoke/Array/MarshalArrayAsParam/AsDefault/AsDefaultTest.cs
index 8ae8690c03c8a7..d30ef8bf9a2e73 100644
--- a/src/tests/Interop/PInvoke/Array/MarshalArrayAsParam/AsDefault/AsDefaultTest.cs
+++ b/src/tests/Interop/PInvoke/Array/MarshalArrayAsParam/AsDefault/AsDefaultTest.cs
@@ -334,7 +334,7 @@ private static void TestMarshalByVal_NoAttributes()
 
         Assert.IsTrue(CStyle_Array_Bool(InitBoolArray(ARRAY_SIZE), ARRAY_SIZE), "CStyle_Array_Bool");
 
-        if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+        if (OperatingSystem.IsWindows())
         {
             object[] oArr = InitArray<object>(ARRAY_SIZE);
             // Test nesting null value scenario
@@ -366,7 +366,7 @@ private static void TestMarshalByVal_In()
         Assert.IsTrue(CStyle_Array_LPSTR_In(strArr, ARRAY_SIZE), "CStyle_Array_LPSTR_In");
         Assert.IsTrue(CStyle_Array_Struct_In(InitStructArray(ARRAY_SIZE), ARRAY_SIZE), "CStyle_Array_Struct_In");
         Assert.IsTrue(CStyle_Array_Bool_In(InitBoolArray(ARRAY_SIZE), ARRAY_SIZE), "CStyle_Array_Bool_In");
-        if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+        if (OperatingSystem.IsWindows())
         {
             object[] oArr = InitArray<object>(ARRAY_SIZE);
             // Test nesting null value scenario
@@ -461,7 +461,7 @@ private static void TestMarshalInOut_ByVal()
         Assert.IsTrue(CStyle_Array_Bool_InOut(boolArr, ARRAY_SIZE), "CStyle_Array_Bool_InOut");
         Assert.IsTrue(Equals<bool>(boolArr, GetExpectedOutBoolArray(ARRAY_SIZE)), "CStyle_Array_Bool_InOut:Equals<bool>");
 
-        if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+        if (OperatingSystem.IsWindows())
         {
             Console.WriteLine("CStyle_Array_Object_InOut");
             object[] oArr = InitArray<object>(ARRAY_SIZE);
@@ -624,7 +624,7 @@ private static void TestMarshalOut_ByVal()
         Assert.IsTrue(CStyle_Array_Bool_Out(boolArr, ARRAY_SIZE), "CStyle_Array_Bool_Out");
         Assert.IsTrue(Equals<bool>(boolArr, GetExpectedOutBoolArray(ARRAY_SIZE)), "CStyle_Array_Bool_Out:Equals<bool>");
 
-        if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+        if (OperatingSystem.IsWindows())
         {
             Console.WriteLine("CStyle_Array_Object_Out");
             object[] oArr = new object[ARRAY_SIZE];
diff --git a/src/tests/Interop/PInvoke/Array/MarshalArrayAsParam/AsLPArray/AsLPArrayTest.cs b/src/tests/Interop/PInvoke/Array/MarshalArrayAsParam/AsLPArray/AsLPArrayTest.cs
index dfd2f88ef5386f..b152744d89cbe0 100644
--- a/src/tests/Interop/PInvoke/Array/MarshalArrayAsParam/AsLPArray/AsLPArrayTest.cs
+++ b/src/tests/Interop/PInvoke/Array/MarshalArrayAsParam/AsLPArray/AsLPArrayTest.cs
@@ -316,7 +316,7 @@ private static void TestMarshalByVal_NoAttributes()
         Assert.IsTrue(CStyle_Array_Struct(InitStructArray(ARRAY_SIZE), ARRAY_SIZE), "CStyle_Array_Struct");
         Assert.IsTrue(CStyle_Array_Bool(InitBoolArray(ARRAY_SIZE), ARRAY_SIZE), "CStyle_Array_Bool");
 
-        if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+        if (OperatingSystem.IsWindows())
         {
             object[] oArr = InitArray<object>(ARRAY_SIZE);
             // Test nesting null value scenario
@@ -349,7 +349,7 @@ private static void TestMarshalByVal_In()
         Assert.IsTrue(CStyle_Array_Struct_In(InitStructArray(ARRAY_SIZE), ARRAY_SIZE), "CStyle_Array_Struct_In");
         Assert.IsTrue(CStyle_Array_Bool_In(InitBoolArray(ARRAY_SIZE), ARRAY_SIZE), "CStyle_Array_Bool_In");
 
-        if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+        if (OperatingSystem.IsWindows())
         {
             object[] oArr = InitArray<object>(ARRAY_SIZE);
             // Test nesting null value scenario
@@ -556,7 +556,7 @@ private static void TestMarshalByVal_Out()
         Assert.IsTrue(CStyle_Array_Bool_Out(boolArr, ARRAY_SIZE), "CStyle_Array_Bool_Out");
         Assert.IsTrue(Equals<bool>(boolArr, GetExpectedOutBoolArray(ARRAY_SIZE)), "CStyle_Array_Bool_Out:Equals<bool>");
         
-        if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+        if (OperatingSystem.IsWindows())
         {
             object[] oArr = new object[ARRAY_SIZE];
             Assert.IsTrue(CStyle_Array_Object_Out(oArr, ARRAY_SIZE), "CStyle_Array_Object_Out");
diff --git a/src/tests/Interop/PInvoke/AsAny/AsAnyTest.cs b/src/tests/Interop/PInvoke/AsAny/AsAnyTest.cs
index c166235753dda8..71c26a8b344936 100644
--- a/src/tests/Interop/PInvoke/AsAny/AsAnyTest.cs
+++ b/src/tests/Interop/PInvoke/AsAny/AsAnyTest.cs
@@ -318,7 +318,7 @@ public static int Main()
             TestUnicodeString();
             TestUnicodeStringArray();
             TestUnicodeStringBuilder();
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            if (OperatingSystem.IsWindows())
             {
                 RunBestFitMappingTests();
             }
diff --git a/src/tests/Interop/PInvoke/Decimal/DecimalTest.cs b/src/tests/Interop/PInvoke/Decimal/DecimalTest.cs
index fd0ea97caaa87b..e98277dd42e5f7 100644
--- a/src/tests/Interop/PInvoke/Decimal/DecimalTest.cs
+++ b/src/tests/Interop/PInvoke/Decimal/DecimalTest.cs
@@ -16,7 +16,7 @@ public static int Main()
         {
             RunDecimalTests();
             RunLPDecimalTests();
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            if (OperatingSystem.IsWindows())
             {
                 RunCurrencyTests();
             }
diff --git a/src/tests/Interop/PInvoke/Delegate/DelegateTest.cs b/src/tests/Interop/PInvoke/Delegate/DelegateTest.cs
index 0ed7d39bbc33d2..37ed43c910b4bf 100644
--- a/src/tests/Interop/PInvoke/Delegate/DelegateTest.cs
+++ b/src/tests/Interop/PInvoke/Delegate/DelegateTest.cs
@@ -124,7 +124,7 @@ static int Main(string[] args)
         try
         {
             TestFunctionPointer();
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            if (OperatingSystem.IsWindows())
             {
                 TestIDispatch();
             }
diff --git a/src/tests/Interop/PInvoke/SizeParamIndex/PInvoke/PassingByOut/PassingByOutTest.cs b/src/tests/Interop/PInvoke/SizeParamIndex/PInvoke/PassingByOut/PassingByOutTest.cs
index ecb94384759661..f56c273bf1abfb 100644
--- a/src/tests/Interop/PInvoke/SizeParamIndex/PInvoke/PassingByOut/PassingByOutTest.cs
+++ b/src/tests/Interop/PInvoke/SizeParamIndex/PInvoke/PassingByOut/PassingByOutTest.cs
@@ -241,7 +241,7 @@ static int Main()
             SizeParamTypeIsUInt32();
             SizeParamTypeIsLong();
             SizeParamTypeIsULong();
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            if (OperatingSystem.IsWindows())
             {
                 SizeParamTypeIsString();
             }
diff --git a/src/tests/Interop/PInvoke/SizeParamIndex/PInvoke/PassingByRef/PassingByRefTest.cs b/src/tests/Interop/PInvoke/SizeParamIndex/PInvoke/PassingByRef/PassingByRefTest.cs
index e86d21db3a1fc9..20e0a20236f3c8 100644
--- a/src/tests/Interop/PInvoke/SizeParamIndex/PInvoke/PassingByRef/PassingByRefTest.cs
+++ b/src/tests/Interop/PInvoke/SizeParamIndex/PInvoke/PassingByRef/PassingByRefTest.cs
@@ -249,7 +249,7 @@ static int Main()
             SizeParamTypeIsUInt32();
             SizeParamTypeIsLong();
             SizeParamTypeIsULong();
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            if (OperatingSystem.IsWindows())
             {
                 SizeParamTypeIsString();
             }
diff --git a/src/tests/Interop/PInvoke/SizeParamIndex/ReversePInvoke/PassingByOut/PassingByOutTest.cs b/src/tests/Interop/PInvoke/SizeParamIndex/ReversePInvoke/PassingByOut/PassingByOutTest.cs
index ec8cd58971c461..bf0c46c83c4f13 100644
--- a/src/tests/Interop/PInvoke/SizeParamIndex/ReversePInvoke/PassingByOut/PassingByOutTest.cs
+++ b/src/tests/Interop/PInvoke/SizeParamIndex/ReversePInvoke/PassingByOut/PassingByOutTest.cs
@@ -184,7 +184,7 @@ public static void RunTestByOut()
         Assert.IsTrue(DoCallBack_MarshalUlongArray_AsParam_AsByOut(new DelUlongArrByOutAsCdeclCaller(TestMethodForUlongArray_AsReversePInvokeByOut_AsCdecl)));
         Console.WriteLine("\t\tMarshalUlongArray_AsReversePInvokeByOut_AsCdecl Passed!");
 
-        if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+        if (OperatingSystem.IsWindows())
         {
             Console.WriteLine("\tScenario 10 : string ==> BSTR, Array_Size = 10, Return_Array_Size = 20");
             Assert.IsTrue(DoCallBack_MarshalStringArray_AsParam_AsByOut(new DelStringArrByOutAsCdeclCaller(TestMethodForStringArray_AsReversePInvokeByOut_AsCdecl)));
diff --git a/src/tests/Interop/PInvoke/SizeParamIndex/ReversePInvoke/PassingByRef/PassingByRefTest.cs b/src/tests/Interop/PInvoke/SizeParamIndex/ReversePInvoke/PassingByRef/PassingByRefTest.cs
index c0b0e7804dda50..13b53e610b6bd1 100644
--- a/src/tests/Interop/PInvoke/SizeParamIndex/ReversePInvoke/PassingByRef/PassingByRefTest.cs
+++ b/src/tests/Interop/PInvoke/SizeParamIndex/ReversePInvoke/PassingByRef/PassingByRefTest.cs
@@ -167,7 +167,7 @@ public static void RunTestByRef()
         Console.WriteLine("\t\tMarshalSbyteArray_AsReversePInvokeByRef_AsCdecl Passed!");
 
         // We don't support exception interop in .NET off-Windows.
-        if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+        if (OperatingSystem.IsWindows())
         {
             Console.WriteLine("\tScenario 3 : short ==> SHORT, Array_Size = -1, Return_Array_Size = 20");
             Assert.Throws<OverflowException>(() => DoCallBack_MarshalShortArray_AsParam_AsByRef(new DelShortArrByRefAsCdeclCaller(TestMethodForShortArray_AsReversePInvokeByRef_AsCdecl)));
@@ -199,7 +199,7 @@ public static void RunTestByRef()
         Assert.IsTrue(DoCallBack_MarshalUlongArray_AsParam_AsByRef(new DelUlongArrByRefAsCdeclCaller(TestMethodForUlongArray_AsReversePInvokeByRef_AsCdecl)));
         Console.WriteLine("\t\tMarshalUlongArray_AsReversePInvokeByRef_AsCdecl Passed!");
 
-        if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+        if (OperatingSystem.IsWindows())
         {
             Console.WriteLine("\tScenario 10 : string ==> BSTR, Array_Size = 10, Return_Array_Size = 20");
             Assert.IsTrue(DoCallBack_MarshalStringArray_AsParam_AsByRef(new DelStringArrByRefAsCdeclCaller(TestMethodForStringArray_AsReversePInvokeByRef_AsCdecl)));
diff --git a/src/tests/Interop/PrimitiveMarshalling/Bool/BoolTest.cs b/src/tests/Interop/PrimitiveMarshalling/Bool/BoolTest.cs
index cff9bb1fbd891a..69df2d5475a2dc 100644
--- a/src/tests/Interop/PrimitiveMarshalling/Bool/BoolTest.cs
+++ b/src/tests/Interop/PrimitiveMarshalling/Bool/BoolTest.cs
@@ -118,7 +118,7 @@ public static int Main(string[] args)
             ReportFailure("Method Marshal_As_Out[Managed Side],The parameter value is changed", boolManaged, boolValue9);
         }
 
-        if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+        if (OperatingSystem.IsWindows())
         {
             TestVariantBool();
         }
diff --git a/src/tests/Interop/StringMarshalling/UTF8/UTF8Test.cs b/src/tests/Interop/StringMarshalling/UTF8/UTF8Test.cs
index 41e394d948d915..6338b1dd866765 100644
--- a/src/tests/Interop/StringMarshalling/UTF8/UTF8Test.cs
+++ b/src/tests/Interop/StringMarshalling/UTF8/UTF8Test.cs
@@ -151,7 +151,7 @@ public static void TestUTF8StructMarshalling(string[] utf8Strings)
             utf8Struct.index = i;
             TestStructWithUtf8Field(utf8Struct);
         }
-        if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+        if (!OperatingSystem.IsWindows())
          CompareWithUTF8Encoding();
 
         string testString = "StructTestString\uD83D\uDE00";
diff --git a/src/tests/Interop/StructMarshalling/ReversePInvoke/MarshalSeqStruct/ReversePInvoke/ReversePInvokeTest_.cs b/src/tests/Interop/StructMarshalling/ReversePInvoke/MarshalSeqStruct/ReversePInvoke/ReversePInvokeTest_.cs
index c4b1e480aadcc4..2e56b1b1cee869 100644
--- a/src/tests/Interop/StructMarshalling/ReversePInvoke/MarshalSeqStruct/ReversePInvoke/ReversePInvokeTest_.cs
+++ b/src/tests/Interop/StructMarshalling/ReversePInvoke/MarshalSeqStruct/ReversePInvoke/ReversePInvokeTest_.cs
@@ -1801,7 +1801,7 @@ private static void Run_TestMethod_DoCallBack_MarshalStructByVal_Cdecl()
         TestMethod_DoCallBack_MarshalStructByVal_Cdecl(StructID.IncludeOuterIntergerStructSequentialId);
         TestMethod_DoCallBack_MarshalStructByVal_Cdecl(StructID.S11Id);
         // Windows X86 has a long standing X86_ONLY logic that causes 3, 5,6,7 byte structure returns to behave incorrectly.
-        if ((RuntimeInformation.ProcessArchitecture != Architecture.X86) || !RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+        if ((RuntimeInformation.ProcessArchitecture != Architecture.X86) || !OperatingSystem.IsWindows())
         {
             TestMethod_DoCallBack_MarshalStructByVal_Cdecl(StructID.ByteStruct3Byte);
         }
@@ -1824,7 +1824,7 @@ private static void Run_TestMethod_DoCallBack_MarshalStructByVal_StdCall()
         TestMethod_DoCallBack_MarshalStructByVal_StdCall(StructID.IncludeOuterIntergerStructSequentialId);
         TestMethod_DoCallBack_MarshalStructByVal_StdCall(StructID.S11Id);
         // Windows X86 has a long standing X86_ONLY logic that causes 3, 5,6,7 byte structure returns to behave incorrectly.
-        if ((RuntimeInformation.ProcessArchitecture != Architecture.X86) || !RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+        if ((RuntimeInformation.ProcessArchitecture != Architecture.X86) || !OperatingSystem.IsWindows())
         {
             TestMethod_DoCallBack_MarshalStructByVal_StdCall(StructID.ByteStruct3Byte);
         }
diff --git a/src/tests/Interop/StructPacking/StructPacking.cs b/src/tests/Interop/StructPacking/StructPacking.cs
index cae74be41b8a09..ec59227b21243d 100644
--- a/src/tests/Interop/StructPacking/StructPacking.cs
+++ b/src/tests/Interop/StructPacking/StructPacking.cs
@@ -286,7 +286,7 @@ static bool TestDouble()
     {
         bool succeeded = true;
 
-        if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows) || (RuntimeInformation.ProcessArchitecture != Architecture.X86))
+        if (OperatingSystem.IsWindows() || (RuntimeInformation.ProcessArchitecture != Architecture.X86))
         {
             succeeded &= Test<DefaultLayoutDefaultPacking<double>>(
                 expectedSize: 16,
@@ -505,7 +505,7 @@ static bool TestInt64()
     {
         bool succeeded = true;
 
-        if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows) || (RuntimeInformation.ProcessArchitecture != Architecture.X86))
+        if (OperatingSystem.IsWindows() || (RuntimeInformation.ProcessArchitecture != Architecture.X86))
         {
             succeeded &= Test<DefaultLayoutDefaultPacking<long>>(
                 expectedSize: 16,
@@ -918,7 +918,7 @@ static bool TestUInt64()
     {
         bool succeeded = true;
 
-        if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows) || (RuntimeInformation.ProcessArchitecture != Architecture.X86))
+        if (OperatingSystem.IsWindows() || (RuntimeInformation.ProcessArchitecture != Architecture.X86))
         {
             succeeded &= Test<DefaultLayoutDefaultPacking<ulong>>(
                 expectedSize: 16,
diff --git a/src/tests/JIT/Regression/CLR-x86-JIT/V1.2-Beta1/b103058/b103058.cs b/src/tests/JIT/Regression/CLR-x86-JIT/V1.2-Beta1/b103058/b103058.cs
index 18bc557a8988a2..dcd3d54e4d2504 100644
--- a/src/tests/JIT/Regression/CLR-x86-JIT/V1.2-Beta1/b103058/b103058.cs
+++ b/src/tests/JIT/Regression/CLR-x86-JIT/V1.2-Beta1/b103058/b103058.cs
@@ -20,7 +20,7 @@ internal unsafe class test
     private static unsafe bool CheckDoubleAlignment1(VT* p)
     {
         Console.WriteLine("Address {0}", (IntPtr)p);
-        if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows) || (RuntimeInformation.ProcessArchitecture != Architecture.X86))
+        if (OperatingSystem.IsWindows() || (RuntimeInformation.ProcessArchitecture != Architecture.X86))
         {
             if ((int)(long)p % sizeof(double) != 0)
             {
diff --git a/src/tests/JIT/Regression/Dev11/External/dev11_239804/ShowLocallocAlignment.cs b/src/tests/JIT/Regression/Dev11/External/dev11_239804/ShowLocallocAlignment.cs
index 4ab7b6c585c493..76e33b31d2585b 100644
--- a/src/tests/JIT/Regression/Dev11/External/dev11_239804/ShowLocallocAlignment.cs
+++ b/src/tests/JIT/Regression/Dev11/External/dev11_239804/ShowLocallocAlignment.cs
@@ -52,7 +52,7 @@ private unsafe static int RunAlignmentCheckScenario()
             void* ptr2;
 
             required_alignment = 16; // Default to the biggest alignment required
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows) && (RuntimeInformation.ProcessArchitecture == Architecture.X86))
+            if (OperatingSystem.IsWindows() && (RuntimeInformation.ProcessArchitecture == Architecture.X86))
             {
                 required_alignment = 4;
             }
diff --git a/src/tests/JIT/superpmi/superpmicollect.cs b/src/tests/JIT/superpmi/superpmicollect.cs
index fc448309566c37..d00272b441ca74 100644
--- a/src/tests/JIT/superpmi/superpmicollect.cs
+++ b/src/tests/JIT/superpmi/superpmicollect.cs
@@ -63,9 +63,9 @@ public static void Initialize()
                 throw new SpmiException("Illegal CORE_ROOT environment variable (" + core_root_raw + "), exception: " + ex.Message);
             }
 
-            IsWindows = RuntimeInformation.IsOSPlatform(OSPlatform.Windows);
-            IsOSX     = RuntimeInformation.IsOSPlatform(OSPlatform.OSX);
-            IsLinux   = RuntimeInformation.IsOSPlatform(OSPlatform.Linux);
+            IsWindows = OperatingSystem.IsWindows();
+            IsOSX     = OperatingSystem.IsMacOS();
+            IsLinux   = OperatingSystem.IsLinux();
 
             if (IsWindows)
             {
diff --git a/src/tests/Loader/AssemblyDependencyResolver/AssemblyDependencyResolverTests/NativeDependencyTests.cs b/src/tests/Loader/AssemblyDependencyResolver/AssemblyDependencyResolverTests/NativeDependencyTests.cs
index 35e8bb3b8484ec..bce770fd2222ec 100644
--- a/src/tests/Loader/AssemblyDependencyResolver/AssemblyDependencyResolverTests/NativeDependencyTests.cs
+++ b/src/tests/Loader/AssemblyDependencyResolver/AssemblyDependencyResolverTests/NativeDependencyTests.cs
@@ -270,7 +270,7 @@ private void ValidateNativeLibraryResolutions(
                     Path.Combine(TestBasePath, _componentAssemblyPath));
 
                 string result = resolver.ResolveUnmanagedDllToPath(lookupName);
-                if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+                if (OperatingSystem.IsWindows())
                 {
                     if (resolvesOnOSes.HasFlag(OS.Windows))
                     {
@@ -281,7 +281,7 @@ private void ValidateNativeLibraryResolutions(
                         Assert.Null(result);
                     }
                 }
-                else if (RuntimeInformation.IsOSPlatform(OSPlatform.OSX))
+                else if (OperatingSystem.IsMacOS())
                 {
                     if (resolvesOnOSes.HasFlag(OS.OSX))
                     {
diff --git a/src/tests/Loader/binding/tracing/BinderTracingTest.DefaultProbing.cs b/src/tests/Loader/binding/tracing/BinderTracingTest.DefaultProbing.cs
index 3ac201a21492da..d61e46cf26eaca 100644
--- a/src/tests/Loader/binding/tracing/BinderTracingTest.DefaultProbing.cs
+++ b/src/tests/Loader/binding/tracing/BinderTracingTest.DefaultProbing.cs
@@ -264,12 +264,12 @@ public static BindOperation SatelliteAssembly_CultureSubdirectory_Lowercase()
                 {
                     FilePath = Helpers.GetProbingFilePath(ProbedPath.PathSource.SatelliteSubdirectory, assemblyName.Name, SatelliteCulture.Name, subdirectoryPath),
                     Source = ProbedPath.PathSource.SatelliteSubdirectory,
-                    Result = RuntimeInformation.IsOSPlatform(OSPlatform.Linux) ? COR_E_FILENOTFOUND : S_OK
+                    Result = OperatingSystem.IsLinux() ? COR_E_FILENOTFOUND : S_OK
                 }
             };
 
             // On Linux, the path with a lower-case culture name should also be probed
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
+            if (OperatingSystem.IsLinux())
             {
                 probedPaths.Add(new ProbedPath()
                     {
@@ -318,7 +318,7 @@ public static BindOperation SatelliteAssembly_NotFound()
             };
 
             // On Linux (case-sensitive), the path with a lower-case culture name should also be probed
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
+            if (OperatingSystem.IsLinux())
             {
                 probedPaths.Add(new ProbedPath()
                     {
diff --git a/src/tests/baseservices/callconvs/TestCallingConventions.cs b/src/tests/baseservices/callconvs/TestCallingConventions.cs
index fe42b6956108ad..6ad86cf135a51f 100644
--- a/src/tests/baseservices/callconvs/TestCallingConventions.cs
+++ b/src/tests/baseservices/callconvs/TestCallingConventions.cs
@@ -16,13 +16,13 @@ class NativeFunctions
 
         public static string GetFileName()
         {
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            if (OperatingSystem.IsWindows())
                 return $"{Name}.dll";
 
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
+            if (OperatingSystem.IsLinux())
                 return $"lib{Name}.so";
 
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.OSX))
+            if (OperatingSystem.IsMacOS())
                 return $"lib{Name}.dylib";
 
             throw new PlatformNotSupportedException();
diff --git a/src/tests/baseservices/typeequivalence/simple/Simple.cs b/src/tests/baseservices/typeequivalence/simple/Simple.cs
index fbfb5dbdb370ed..a65866e58059fc 100644
--- a/src/tests/baseservices/typeequivalence/simple/Simple.cs
+++ b/src/tests/baseservices/typeequivalence/simple/Simple.cs
@@ -216,7 +216,7 @@ private static void TestGenericInterfaceEquivalence()
 
     public static int Main(string[] noArgs)
     {
-        if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+        if (!OperatingSystem.IsWindows())
         {
             return 100;
         }
diff --git a/src/tests/ilasm/PortablePdb/IlasmPortablePdbTester.cs b/src/tests/ilasm/PortablePdb/IlasmPortablePdbTester.cs
index 221e22ee4e126c..5b697d5802759a 100644
--- a/src/tests/ilasm/PortablePdb/IlasmPortablePdbTester.cs
+++ b/src/tests/ilasm/PortablePdb/IlasmPortablePdbTester.cs
@@ -22,7 +22,7 @@ public class IlasmPortablePdbTester : XunitBase
         public IlasmPortablePdbTester()
         {
             CoreRootVar = Environment.GetEnvironmentVariable(CoreRoot);
-            IsUnix = !RuntimeInformation.IsOSPlatform(OSPlatform.Windows);
+            IsUnix = !OperatingSystem.IsWindows();
             NativeExtension = IsUnix ? string.Empty : ".exe";
             IlasmFile = IlasmFileName + NativeExtension;
         }
diff --git a/src/tests/readytorun/coreroot_determinism/Program.cs b/src/tests/readytorun/coreroot_determinism/Program.cs
index f836feda5d7ad5..ea537f274e439b 100644
--- a/src/tests/readytorun/coreroot_determinism/Program.cs
+++ b/src/tests/readytorun/coreroot_determinism/Program.cs
@@ -63,7 +63,7 @@ public static int CompareDLLs(string folder1, string folder2)
         return result;
     }
 
-    public static string OSExeSuffix(string path) => (RuntimeInformation.IsOSPlatform(OSPlatform.Windows) ? path + ".exe" : path);
+    public static string OSExeSuffix(string path) => (OperatingSystem.IsWindows() ? path + ".exe" : path);
 
     private static void PrepareCompilationInputFolder(string coreRootFolder, string compilationInputFolder)
     {
diff --git a/src/tests/readytorun/r2rdump/FrameworkTests/R2RDumpTester.cs b/src/tests/readytorun/r2rdump/FrameworkTests/R2RDumpTester.cs
index 2d813eb31055a9..18c1f0cd217dbb 100644
--- a/src/tests/readytorun/r2rdump/FrameworkTests/R2RDumpTester.cs
+++ b/src/tests/readytorun/r2rdump/FrameworkTests/R2RDumpTester.cs
@@ -15,7 +15,7 @@ public class R2RDumpTester : XunitBase
         
         public static string FindExePath(string exe)
         {
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            if (OperatingSystem.IsWindows())
             {
                 exe = exe + ".exe";
             }
@@ -40,7 +40,7 @@ public static string FindExePath(string exe)
         public void DumpCoreLib()
         {
             string CoreRootVar = Environment.GetEnvironmentVariable(CoreRoot);
-            bool IsUnix = !RuntimeInformation.IsOSPlatform(OSPlatform.Windows);
+            bool IsUnix = !OperatingSystem.IsWindows();
             string R2RDumpAbsolutePath = Path.Combine(CoreRootVar, R2RDumpRelativePath, R2RDumpFile);
             string CoreLibFile = "System.Private.CoreLib.dll";
             string CoreLibAbsolutePath = Path.Combine(CoreRootVar, CoreLibFile);
diff --git a/src/tests/tracing/eventpipe/common/IpcTraceTest.cs b/src/tests/tracing/eventpipe/common/IpcTraceTest.cs
index 660efdf09fe6af..7a9b9fd0c19503 100644
--- a/src/tests/tracing/eventpipe/common/IpcTraceTest.cs
+++ b/src/tests/tracing/eventpipe/common/IpcTraceTest.cs
@@ -347,7 +347,7 @@ private int Validate()
         // the process that created them, so we don't need to check on that platform.
         static public bool EnsureCleanEnvironment()
         {
-            if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            if (!OperatingSystem.IsWindows())
             {
                 Func<(IEnumerable<IGrouping<int,FileInfo>>, List<int>)> getPidsAndSockets = () =>
                 {
diff --git a/src/tests/tracing/eventpipe/common/IpcUtils.cs b/src/tests/tracing/eventpipe/common/IpcUtils.cs
index 6828254159e3b4..6f60368894d7e9 100644
--- a/src/tests/tracing/eventpipe/common/IpcUtils.cs
+++ b/src/tests/tracing/eventpipe/common/IpcUtils.cs
@@ -375,7 +375,7 @@ private static IpcMessage Read(Stream stream)
 
     public class ConnectionHelper
     {
-        private static string IpcRootPath { get; } = RuntimeInformation.IsOSPlatform(OSPlatform.Windows) ? @"\\.\pipe\" : Path.GetTempPath();
+        private static string IpcRootPath { get; } = OperatingSystem.IsWindows() ? @"\\.\pipe\" : Path.GetTempPath();
         public static Stream GetStandardTransport(int processId)
         {
             try
@@ -391,7 +391,7 @@ public static Stream GetStandardTransport(int processId)
                 throw new Exception($"Process {processId} seems to be elevated.");
             }
 
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            if (OperatingSystem.IsWindows())
             {
                 string pipeName = $"dotnet-diagnostic-{processId}";
                 var namedPipe = new NamedPipeClientStream(
diff --git a/src/tests/tracing/eventpipe/common/Reverse.cs b/src/tests/tracing/eventpipe/common/Reverse.cs
index fd5693a6be9c35..b301cf59598f10 100644
--- a/src/tests/tracing/eventpipe/common/Reverse.cs
+++ b/src/tests/tracing/eventpipe/common/Reverse.cs
@@ -70,7 +70,7 @@ public class ReverseServer
     {
         public static string MakeServerAddress()
         {
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            if (OperatingSystem.IsWindows())
             {
                 return "DOTNET_TRACE_TESTS_" + Path.GetRandomFileName();
             }
@@ -89,7 +89,7 @@ public ReverseServer(string serverAddress, int bufferSize = 16 * 1024)
         {
             _serverAddress = serverAddress;
             _bufferSize = bufferSize;
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            if (OperatingSystem.IsWindows())
             {
                 _server = GetNewNamedPipeServer();
             }
@@ -135,7 +135,7 @@ public async Task<Stream> AcceptAsync()
 
         private NamedPipeServerStream GetNewNamedPipeServer()
         {
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            if (OperatingSystem.IsWindows())
             {
                 return new NamedPipeServerStream(
                     _serverAddress,
diff --git a/src/tests/tracing/eventpipe/complus_config/name_config_with_pid.cs b/src/tests/tracing/eventpipe/complus_config/name_config_with_pid.cs
index 41b5421ec4c576..7cca9d64320bb4 100644
--- a/src/tests/tracing/eventpipe/complus_config/name_config_with_pid.cs
+++ b/src/tests/tracing/eventpipe/complus_config/name_config_with_pid.cs
@@ -32,7 +32,7 @@ static int Main(string[] args)
             }
 
             string corerun = Path.Combine(Environment.GetEnvironmentVariable("CORE_ROOT"), "corerun");
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            if (OperatingSystem.IsWindows())
                 corerun = corerun + ".exe";
 
             // Use dll directory as temp directory
diff --git a/src/tests/tracing/eventpipe/processinfo/processinfo.cs b/src/tests/tracing/eventpipe/processinfo/processinfo.cs
index d79e8147b739ac..ebeb602e8f014a 100644
--- a/src/tests/tracing/eventpipe/processinfo/processinfo.cs
+++ b/src/tests/tracing/eventpipe/processinfo/processinfo.cs
@@ -62,7 +62,7 @@ public static string NormalizeCommandLine(string cmdline)
 
             // Tests are run out of /tmp on Mac and linux, but on Mac /tmp is actually a symlink that points to /private/tmp.
             // This isn't represented in the output from FileInfo.FullName unfortunately, so we'll fake that completion in that case.
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.OSX) && normalizedCommandLine.StartsWith("/tmp/"))
+            if (OperatingSystem.IsMacOS() && normalizedCommandLine.StartsWith("/tmp/"))
                 normalizedCommandLine = "/private" + normalizedCommandLine;
 
             return normalizedCommandLine;
@@ -146,15 +146,15 @@ public static int Main(string[] args)
 
             // see eventpipeeventsource.cpp for these values
             string expectedOSValue = null;
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            if (OperatingSystem.IsWindows())
             {
                 expectedOSValue = "Windows";
             }
-            else if (RuntimeInformation.IsOSPlatform(OSPlatform.OSX))
+            else if (OperatingSystem.IsMacOS())
             {
                 expectedOSValue = "macOS";
             }
-            else if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
+            else if (OperatingSystem.IsLinux())
             {
                 expectedOSValue = "Linux";
             }