XCTest

default testing framework, bundled with the Xcode IDE.

📙 書籍

• Test-Driven Development in Swift (2021)

📘 手冊

• help

code

XCTestCase offers methods to run code before each test or all the tests will run, as well as after each test or all the tests did run:

import XCTest
@testable import MyProject

// ⭐️ make a subclass of XCTestCase
class TestsForMyType: XCTestCase {

    /* -------- test case life cycle -------- */
    
    // ⭐️ runs before ALL tests
    override class func setUp() { ... }
    
    // ⭐️ runs after all tests
    override class func tearDown() { ... }
    
    // ⭐️ runs before each test
    override func setUpWithError() throws { ... }

    // ⭐️ runs after each test
    override func tearDownWithError() throws { ... }

    /* -------- test cases -------- */
 
    // ⭐️ method name starting with “test”
    func testThis() { } 
    func testThat() { } 

    // ⭐️ performance test case name starting with “testPerformance”?
    func testPerformanceExample() throws {
        self.measure {
            // code to measure the time of
        }
    }
}

Bool

• XCTAssertTrue(true)

• XCTAssertFalse(false)

Compare

compare the values of types conforming to Comparable:

• XCTAssertLessThan(1, 2)

• XCTAssertGreaterThan(2, 1)

• XCTAssertLessThanOrEqual(2, 2)

• XCTAssertGreaterThanOrEqual(2, 1)

Nil

• XCTAssertNil(nil)

• XCTAssertNotNil("this is not nil")

// will fail if user == nil, or firstName !== "John"
XCTAssertEqual(user?.firstName, "John")

// use `XCTUnwrap` instead
let u = try XCTUnwrap(user)            // fail if user == nil
XCTAssertEqual(u.firstName, "John")    // fail if not equal

Throws

• XCTAssertThrowsError(try aFunctionThatThrows())

• XCTAssertNoThrow(try aFunctionThatThrows())