【iOS】Swift Testingで単体テストの実装方法と#expect/#requireの使い方！

import Testing

struct StructTest {
    @Test func example() { }
}

actor ActorTest {
    @Test func example() {}
}

@Test func animalTest() {
    // 複数検証してもOK 
    let result = "Cat"
    print("------1")
    #expect(result == "Cat")
    print("------2")
    // 失敗(false)しても後続の処理は行われる
    #expect(result.contains("S")) // Expectation failed: (result → "Cat").contains("S" → S)
    print("------3")
    #expect(result.contains("C"))
    print("------4")
}

ログ
◇ Test run started.
↳ Testing Library Version: 102 (arm64-apple-ios13.0-simulator)
◇ Suite SampleAppTests started.
◇ Test animalTest() started.
------1
------2
✘ Test animalTest() recorded an issue at ClipImageAppTests.swift:17:9: Expectation failed: (result → "Cat").contains("S" → S)
------3
------4
✘ Test animalTest() failed after 0.001 seconds with 1 issue.
✘ Suite SampleAppTests failed after 0.001 seconds with 1 issue.
✘ Test run with 1 test failed after 0.002 seconds with 1 issue.

◇ Test run started.
↳ Testing Library Version: 102 (arm64-apple-ios13.0-simulator)
◇ Suite SampleAppTests started.
◇ Test animalTest() started.
✔ Test animalTest() passed after 0.001 seconds.
✔ Suite SampleAppTests passed after 0.001 seconds.
✔ Test run with 1 test passed after 0.001 seconds.

@Test func animalNullTest() {
    print("------1")
    let result: String? = nil
    do {
        print("------2")
        // 失敗すると後続の処理は行わない
        let nonNull = try #require(result)
        print("------3")
        #expect(nonNull != nil)
    } catch {
        // 失敗はキャッチできる
        print("ERROR：", error)
    }
}

ログ
◇ Test run started.
↳ Testing Library Version: 102 (arm64-apple-ios13.0-simulator)
◇ Suite SampleAppTests started.
◇ Test animalNullTest() started.
------1
------2
✘ Test animalNullTest() recorded an issue at SampleAppTests.swift:29:31: Expectation failed: result → nil
ERROR： ExpectationFailedError(expectation: Testing.Expectation(evaluatedExpression: Testing.__Expression.Kind.generic("result"), mismatchedErrorDescription: nil, differenceDescription: nil, mismatchedExitConditionDescription: nil, isPassing: false, isRequired: true, sourceLocation: SampleAppTests/SampleAppTests.swift:29:31))
✘ Test animalNullTest() failed after 0.006 seconds with 1 issue.
✘ Suite SampleAppTests failed after 0.006 seconds with 1 issue.
✘ Test run with 1 test failed after 0.006 seconds with 1 issue.

@Test("動物名確認テスト")
func animalTest() {
    let result = "Cat"
    #expect(result == "Cat")
}

@Test func animalTest() async throws { ... }

@Test(arguments: ["Cat", "Dog", "Lion"])
func animalTest(animal: String) {
    #expect(animal == "Cat")
}

@Test(arguments: 1...99)
func someIntTest(_ value: Int) {
  #expect(int > 50)
}

@Test() func threadCheck() {
    // Expectation failed: (Thread → NSThread).isMainThread → false
    #expect(Thread.isMainThread)
}

@Test()
@MainActor
func threadCheckMain() {
    // 成功：メインスレッドで実行される
    #expect(Thread.isMainThread)
}

// 複数のスイートやテストケースを包括したスイート
@Suite
struct AllTests {
    static let allTests = [
        UserTests.self,
        MathTests.self,
        NetworkTests.self
    ]
}
// @Suiteを宣言しなくても暗黙的にスイートとして識別される
struct UserTests {
    @Test func someTest() { }
}

@Suite("ユーザー登録テスト")