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swift-testing

Sep 14, 20242 min read

Swift Testing - Xcode - Apple Developer

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Cheat Sheet

  • withKnownIssues mark a failing test as known so that it will still pass.
    • This is helpful for passing CI tests for issues that can’t be fixed right now

Use #require to unwrap

let unwrapped = try #require(last, "the last value should be 4")
#expect(unwrapped == 4)

Passing in parameters into a test

@Test("Continents mentioned in videos", arguments: [
    "A Beach",
    "By the Lake",
    "Camping in the Woods"
])
func mentionedContinents(videoName: String) async throws {
    let videoLibrary = try await VideoLibrary()
    let video = try #require(await videoLibrary.video(named: videoName))
    #expect(video.mentionedContinents.count <= 3)
}

Passing multiple parameters

arguments can receive anything conforming to Collection. Here are a few examples.

// Array of Tuples
@Test(arguments: [(1, 2), (2, 4)])
func double(input: Int, result: Int) {
  #expect(input * 2 == result)
}
 
// Dictionary
@Test(arguments: [
  1: 2,
  2: 4,
])
func double(input: Int, result: Int) {
  #expect(input * 2 == result)
}
 
// multiple arrays
let input = [1,2]
let result = [2,4]
@Test(arguments: input, result)
func double(input: Int, result: Int) {
  #expect(input * 2 == result)
}
 
// zipped arrays
@Test(arguments: zip(input,result))
func double(input: Int, result: Int) {
  #expect(input * 2 == result)
}

Serial vs. Parallel

Swift Testing is parallel by default.

To guarantee that a test suite is run in a particular order use @Suite(.serialized. By using this, you will guarantee that the tests are run in a particular order. However, your tests will take longer because they cannot be run in parallel.

Migrating from XCTest

Use Issue.record instead of XCTFail

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