Quick · ikesyo · May 17, 2021 · Apr 2, 2019 · May 14, 2021 · May 14, 2021
diff --git a/Nimble.xcodeproj/project.pbxproj b/Nimble.xcodeproj/project.pbxproj
@@ -24,6 +24,12 @@
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+		106112BD2251DFE7000A5848 /* BeResult.swift in Sources */ = {isa = PBXBuildFile; fileRef = 106112BC2251DFE7000A5848 /* BeResult.swift */; };
+		106112C02251E0FA000A5848 /* BeResult.swift in Sources */ = {isa = PBXBuildFile; fileRef = 106112BC2251DFE7000A5848 /* BeResult.swift */; };
+		106112C22251E0FD000A5848 /* BeResult.swift in Sources */ = {isa = PBXBuildFile; fileRef = 106112BC2251DFE7000A5848 /* BeResult.swift */; };
+		106112C52251E13B000A5848 /* BeResultTest.swift in Sources */ = {isa = PBXBuildFile; fileRef = 106112C42251E13B000A5848 /* BeResultTest.swift */; };
+		106112C62251E13B000A5848 /* BeResultTest.swift in Sources */ = {isa = PBXBuildFile; fileRef = 106112C42251E13B000A5848 /* BeResultTest.swift */; };
+		106112C72251E13B000A5848 /* BeResultTest.swift in Sources */ = {isa = PBXBuildFile; fileRef = 106112C42251E13B000A5848 /* BeResultTest.swift */; };
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 		0477153423B740AD00402D4E /* DispatchTimeInterval.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = DispatchTimeInterval.swift; sourceTree = "<group>"; };
+		106112BC2251DFE7000A5848 /* BeResult.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = BeResult.swift; sourceTree = "<group>"; };
+		106112C42251E13B000A5848 /* BeResultTest.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = BeResultTest.swift; sourceTree = "<group>"; };
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 				1F925EEE195C136500ED456B /* BeLogicalTest.swift */,
 				1F925EF8195C175000ED456B /* BeNilTest.swift */,
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 				7B13BA091DD360DE00C9098C /* ContainElementSatisfyingTest.swift */,
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 				1FD8CD171968AB07008ED995 /* BeLogical.swift */,
 				1FD8CD181968AB07008ED995 /* BeNil.swift */,
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 				1FD8CD401968AB07008ED995 /* BeCloseTo.swift in Sources */,
 				1F1871C81CA89EDB00A34BF2 /* NMBExceptionCapture.m in Sources */,
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 				1FD8CD321968AB07008ED995 /* NimbleXCTestHandler.swift in Sources */,
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 				7B13BA111DD361EB00C9098C /* ObjCContainElementSatisfyingTest.m in Sources */,
 				1F925EF6195C147800ED456B /* BeCloseToTest.swift in Sources */,
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 				1F5DF18C1BDCA0F500C3A531 /* Await.swift in Sources */,
 				1F1871D81CA89EEF00A34BF2 /* NMBStringify.m in Sources */,
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 				CD79C9A31D2CC841004B6F9A /* ObjCBeFalseTest.m in Sources */,
 				1F5DF1A71BDCA10200C3A531 /* EqualTest.swift in Sources */,
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 				1FD8CD411968AB07008ED995 /* BeCloseTo.swift in Sources */,
 				1F1871D31CA89EEE00A34BF2 /* NMBExceptionCapture.m in Sources */,
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diff --git a/README.md b/README.md
@@ -51,6 +51,7 @@ expect(ocean.isClean).toEventually(beTruthy())
   - [Collection Elements](#collection-elements)
   - [Collection Count](#collection-count)
   - [Notifications](#notifications)
+  - [Result](#result)
   - [Matching a value to any of a group of matchers](#matching-a-value-to-any-of-a-group-of-matchers)
   - [Custom Validation](#custom-validation)
 - [Writing Your Own Matchers](#writing-your-own-matchers)
@@ -1197,6 +1198,37 @@ expect {
 
 > This matcher is only available in Swift.
 
+## Result
+
+```swift
+// Swift
+let aResult: Result<String, Error> = .success("Hooray") 
+
+// passes if result is .success
+expect(aResult).to(beSuccess()) 
+
+// passes if result value is .success and validates Success value
+expect(aResult).to(beSuccess { value in
+    expect(value).to(equal("Hooray"))
+})
+
+
+enum AnError: Error {
+    case somethingHappened
+}
+let otherResult: Result<String, AnError> = .failure(.somethingHappened) 
+
+// passes if result is .failure
+expect(otherResult).to(beFailure()) 
+
+// passes if result value is .failure and validates error
+expect(otherResult).to(beFailure { error in
+    expect(error).to(matchError(AnError.somethingHappened))
+}) 
+```
+
+> This matcher is only available in Swift.
+
 ## Matching a value to any of a group of matchers
 
 ```swift

diff --git a/Sources/Nimble/Matchers/BeResult.swift b/Sources/Nimble/Matchers/BeResult.swift
@@ -0,0 +1,67 @@
+import Foundation
+
+/// A Nimble matcher for Result that succeeds when the actual value is success.
+///
+/// You can pass a closure to do any arbitrary custom matching to the value inside result.
+/// The closure only gets called when the result is success.
+public func beSuccess<Success, Failure>(
+    test: ((Success) -> Void)? = nil
+) -> Predicate<Result<Success, Failure>> {
+    return Predicate.define { expression in
+        var rawMessage = "be <success(\(Success.self))>"
+        if test != nil {
+            rawMessage += " that satisfies block"
+        }
+        let message = ExpectationMessage.expectedActualValueTo(rawMessage)
+
+        guard case let .success(value)? = try expression.evaluate() else {
+            return PredicateResult(status: .doesNotMatch, message: message)
+        }
+
+        var matches = true
+        if let test = test {
+            let assertions = gatherFailingExpectations {
+                test(value)
+            }
+            let messages = assertions.map { $0.message }
+            if !messages.isEmpty {
+                matches = false
+            }
+        }
+
+        return PredicateResult(bool: matches, message: message)
+    }
+}
+
+/// A Nimble matcher for Result that succeeds when the actual value is failure.
+///
+/// You can pass a closure to do any arbitrary custom matching to the error inside result.
+/// The closure only gets called when the result is failure.
+public func beFailure<Success, Failure>(
+    test: ((Failure) -> Void)? = nil
+) -> Predicate<Result<Success, Failure>> {
+    return Predicate.define { expression in
+        var rawMessage = "be <failure(\(Failure.self))>"
+        if test != nil {
+            rawMessage += " that satisfies block"
+        }
+        let message = ExpectationMessage.expectedActualValueTo(rawMessage)
+
+        guard case let .failure(error)? = try expression.evaluate() else {
+            return PredicateResult(status: .doesNotMatch, message: message)
+        }
+
+        var matches = true
+        if let test = test {
+            let assertions = gatherFailingExpectations {
+                test(error)
+            }
+            let messages = assertions.map { $0.message }
+            if !messages.isEmpty {
+                matches = false
+            }
+        }
+
+        return PredicateResult(bool: matches, message: message)
+    }
+}
diff --git a/Tests/NimbleTests/Matchers/BeResultTest.swift b/Tests/NimbleTests/Matchers/BeResultTest.swift
@@ -0,0 +1,104 @@
+import XCTest
+import Nimble
+
+private struct StubError: Error, CustomDebugStringConvertible {
+    let debugDescription = "StubError"
+}
+
+enum TestError: Error, Equatable, CustomDebugStringConvertible {
+    case foo, bar
+
+    var debugDescription: String {
+        switch self {
+        case .foo:
+            return "TestError.foo"
+        case .bar:
+            return "TestError.bar"
+        }
+    }
+}
+
+final class BeSuccessTest: XCTestCase {
+    func testPositiveMatch() {
+        let result: Result<Int, Error> = .success(1)
+        expect(result).to(beSuccess())
+    }
+
+    func testPositiveMatchWithClosure() {
+        let stubValue = 1
+        let result: Result<Int, Error> = .success(stubValue)
+        expect(result).to(beSuccess { value in
+            expect(value).to(equal(stubValue))
+        })
+    }
+
+    func testPositiveNegatedMatch() {
+        let result: Result<Int, Error> = .failure(StubError())
+        expect(result).toNot(beSuccess())
+    }
+
+    func testNegativeMatches() {
+        failsWithErrorMessage("expected to be <success(Int)>, got <failure(StubError)>") {
+            let result: Result<Int, Error> = .failure(StubError())
+            expect(result).to(beSuccess())
+        }
+        failsWithErrorMessage("expected to not be <success(Int)>, got <success(1)>") {
+            let result: Result<Int, Error> = .success(1)
+            expect(result).toNot(beSuccess())
+        }
+
+        failsWithErrorMessage("expected to be <success(Int)> that satisfies block, got <success(1)>") {
+            let result: Result<Int, Error> = .success(1)
+            expect(result).to(beSuccess { _ in
+                fail()
+            })
+        }
+    }
+}
+
+final class BeFailureTest: XCTestCase {
+    func testPositiveMatch() {
+        let result: Result<Int, Error> = .failure(StubError())
+        expect(result).to(beFailure())
+    }
+
+    func testPositiveMatchWithClosure() {
+        let result: Result<Int, Error> = .failure(StubError())
+        expect(result).to(beFailure { error in
+            expect(error).to(matchError(StubError.self))
+        })
+
+        expect(Result<Int, TestError>.failure(.foo)).to(beFailure { error in
+            expect(error).to(equal(.foo))
+        })
+    }
+
+    func testPositiveNegatedMatch() {
+        let result: Result<Int, Error> = .success(1)
+        expect(result).toNot(beFailure())
+    }
+
+    func testNegativeMatches() {
+        failsWithErrorMessage("expected to be <failure(Error)>, got <success(1)>") {
+            let result: Result<Int, Error> = .success(1)
+            expect(result).to(beFailure())
+        }
+        failsWithErrorMessage("expected to not be <failure(Error)>, got <failure(StubError)>") {
+            let result: Result<Int, Error> = .failure(StubError())
+            expect(result).toNot(beFailure())
+        }
+
+        failsWithErrorMessage("expected to be <failure(Error)> that satisfies block, got <failure(StubError)>") {
+            let result: Result<Int, Error> = .failure(StubError())
+            expect(result).to(beFailure { _ in
+                fail()
+            })
+        }
+        failsWithErrorMessage("expected to be <failure(TestError)> that satisfies block, got <failure(TestError.foo)>") {
+            let result: Result<Int, TestError> = .failure(.foo)
+            expect(result).to(beFailure { error in
+                expect(error).to(equal(.bar))
+            })
+        }
+    }
+}