From 24c6bb66ddae903697a9041ea49a34a50fceb7f6 Mon Sep 17 00:00:00 2001
From: David <github.site@torick.net>
Date: Wed, 29 Nov 2023 17:30:11 -0500
Subject: [PATCH] test: Validate the WhereNotNull behavior

---
 .../Factories/Given_WhereNotNullFactories.cs  | 50 +++++++++++++++++++
 .../Operators/Given_WhereFeed.CoreRules.cs    |  2 +-
 2 files changed, 51 insertions(+), 1 deletion(-)
 create mode 100644 src/Uno.Extensions.Reactive.Tests/Factories/Given_WhereNotNullFactories.cs

diff --git a/src/Uno.Extensions.Reactive.Tests/Factories/Given_WhereNotNullFactories.cs b/src/Uno.Extensions.Reactive.Tests/Factories/Given_WhereNotNullFactories.cs
new file mode 100644
index 0000000000..e875c74ca5
--- /dev/null
+++ b/src/Uno.Extensions.Reactive.Tests/Factories/Given_WhereNotNullFactories.cs
@@ -0,0 +1,50 @@
+using System;
+using System.Linq;
+using FluentAssertions;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+using Uno.Extensions.Reactive.Testing;
+
+namespace Uno.Extensions.Reactive.Tests.Factories;
+
+[TestClass]
+public class Given_WhereNotNullFactories : FeedTests
+{
+	public record MyObject;
+	public record struct MyStruct;
+
+	[TestMethod]
+	public async Task When_InputIsSomeNull_Then_TreatAsNone()
+	{
+		await Feed<MyObject?>.Async(async _ => default(MyObject?)).WhereNotNull().Record().Should().BeAsync(m => m.Message(Data.None));
+		await Feed<MyStruct?>.Async(async _ => default(MyStruct?)).WhereNotNull().Record().Should().BeAsync(m => m.Message(Data.None));
+		await Feed<string?>.Async(async _ => default(string?)).WhereNotNull().Record().Should().BeAsync(m => m.Message(Data.None));
+		await Feed<int?>.Async(async _ => default(int?)).WhereNotNull().Record().Should().BeAsync(m => m.Message(Data.None));
+	}
+
+	[TestMethod]
+	public async Task When_InputIsSomeNotNull_Then_StaySome()
+	{
+		await Feed<MyObject?>.Async(async _ => new MyObject()).WhereNotNull().Record().Should().BeAsync(m => m.Message(Data.Some));
+		await Feed<MyStruct?>.Async(async _ => new MyStruct()).WhereNotNull().Record().Should().BeAsync(m => m.Message(Data.Some));
+		await Feed<string?>.Async(async _ => "").WhereNotNull().Record().Should().BeAsync(m => m.Message(""));
+		await Feed<int?>.Async(async _ => 42).WhereNotNull().Record().Should().BeAsync(m => m.Message(42));
+	}
+
+	[TestMethod]
+	public async Task When_InputUndefined_Then_StayUndefined()
+	{
+		await Feed<MyObject?>.Async(async _ => Option<MyObject?>.Undefined()).WhereNotNull().Record().Should().BeAsync(m => m.Message(Data.Undefined));
+		await Feed<MyStruct?>.Async(async _ => Option<MyStruct?>.Undefined()).WhereNotNull().Record().Should().BeAsync(m => m.Message(Data.Undefined));
+		await Feed<string?>.Async(async _ => Option<string?>.Undefined()).WhereNotNull().Record().Should().BeAsync(m => m.Message(Data.Undefined));
+		await Feed<int?>.Async(async _ => Option<int?>.Undefined()).WhereNotNull().Record().Should().BeAsync(m => m.Message(Data.Undefined));
+	}
+
+	[TestMethod]
+	public async Task When_InputIsNone_Then_StayNone()
+	{
+		await Feed<MyObject?>.Async(async _ => Option<MyObject?>.None()).WhereNotNull().Record().Should().BeAsync(m => m.Message(Data.None));
+		await Feed<MyStruct?>.Async(async _ => Option<MyStruct?>.None()).WhereNotNull().Record().Should().BeAsync(m => m.Message(Data.None));
+		await Feed<string?>.Async(async _ => Option<string?>.None()).WhereNotNull().Record().Should().BeAsync(m => m.Message(Data.None));
+		await Feed<int?>.Async(async _ => Option<int?>.None()).WhereNotNull().Record().Should().BeAsync(m => m.Message(Data.None));
+	}
+}
diff --git a/src/Uno.Extensions.Reactive.Tests/Operators/Given_WhereFeed.CoreRules.cs b/src/Uno.Extensions.Reactive.Tests/Operators/Given_WhereFeed.CoreRules.cs
index e2a836f231..a21d2267a8 100644
--- a/src/Uno.Extensions.Reactive.Tests/Operators/Given_WhereFeed.CoreRules.cs
+++ b/src/Uno.Extensions.Reactive.Tests/Operators/Given_WhereFeed.CoreRules.cs
@@ -14,7 +14,7 @@ public partial class Given_WhereFeed : FeedTests
 	public async Task When_WhereFeed_Then_CompilesToCoreRules()
 		=> await FeedCoreRules
 			.Using(Feed.Async(async _ => new MyRecord(42)))
-			.WhenFeed(src => new WhereFeed<MyRecord>(src, _ => true))
+			.WhenFeed(src => new WhereFeed<MyRecord>(src, (MyRecord _) => true))
 			.Then_CompilesToCoreRules(CT);
 
 	private record MyRecord(int Value);