XCTest'ing 元组 [英] XCTest'ing a tuple

问题描述

我正在尝试像这样构建单元测试:

I am trying to build a unit test like so:

// region is a (Double, Double) tuple
XCTAssertEqual(region, (0.0, 200.0))

但是 Xcode 给了我一个错误:无法使用类型为 ((Double, Double), (Double, Double)) 的参数列表调用 'XCTAssertEqual'

But Xcode is giving me an error: Cannot invoke 'XCTAssertEqual' with an argument list of type ((Double, Double), (Double, Double))

是否有不同的方法来测试元组而不提取其成员并单独测试?

Is there a different way to test tuples without extracting their members and testing individually?

推荐答案

XCTAssertEqual 要求传递给它的两个参数是Equatable，从方法中可以看出签名.注意expression1返回T?，T必须是Equatable:

XCTAssertEqual requires that the two parameters passed to it are Equatable, which you can see from the method signature. Note that expression1 returns T?, and T must be Equatable:

func XCTAssertEqual<T : Equatable>(_ expression1: @autoclosure () throws -> T?, _ expression2: @autoclosure () throws -> T?, _ message: @autoclosure () -> String = default, file: StaticString = #file, line: UInt = #line)

但是 Swift 元组不是 Equatable，因此您不能将它们与 XCTAssertEqual 一起使用.

元组do有一个 == 方法——它们只是不符合协议——所以你可以做这样的事情:

Tuples do have an == method — they just don't conform to the protocol — so you could do something like this:

let eql = region == (0.0, 200.0)
XCTAssertTrue(eql)

甚至:

XCTAssertTrue(region == (0.0, 200.0))

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