javascript - 异步测试功能

Question

我正在尝试创建一个函数来测试异步代码，但我有点迷茫，我希望下面的 TEST_F 和 TEST 函数也适用于异步代码，例如加载图像。

const CHECK = (actual, expected) => {
    return (actual === expected);
};

const TEST = (name, ...testFunctions) => {
    console.log(name+':');
    for (let test of testFunctions)
        console.log(test);
};

const TEST_F = (name, f) => {
    const tStart = performance.now();

    const check = f();

    const tEnd = performance.now();
    const duration = tEnd - tStart;

    const details = name + ': ' + '(' + duration + ') = ' + check;

    return details;
};

const imageDownload = (path, successCallback) => {
    let img = new Image();

    img.addEventListener("load", successCallback, false);

    img.src = path;

    return img;
};

TEST("TestImage", 
    TEST_F("testImageDownload", () => {
        let spyCountSuccess = 0;
        const expectedCountSuccess = spyCountSuccess + 1;

        const successCallback = () => {
            spyCountSuccess++;
        };
        const pathImage = 'https://i.imgur.com/Wutekcp.jpg';
        imageDownload(pathImage, successCallback);

        const actualCountSuccess = spyCountSuccess;

        return CHECK(actualCountSuccess, expectedCountSuccess);
    })

);

使用上面的代码，即使加载了图像，我也总是会出错，因为我没有正确处理异步的概念，我想了解如何调整代码从而也测试 ascincrono 代码。

标签： javascriptunit-testingasynchronoustesting

Answer 1

经过一些测试，我能够测试异步代码。我不知道我是否会保持这种方式，但它正在工作，我会尝试研究这些行，看看我能改进什么：

const CHECK = (actual, expected) => {
    return (actual === expected);
};

const TEST = (name, ...testFunctions) => {
    console.log(name+':');
    for (let test of testFunctions)
        if(test === undefined)
            continue;
        else
            console.log(test);
};

const TEST_F = (name, f) => {
    const tStart = performance.now();
    const check = f();
    const tEnd = performance.now();
    const duration = tEnd - tStart;
    
    const details = name + ': ' + '(' + duration + ') = ' + check;
  
    return details;
};

const TEST_F_ASYNC = (name, f) => {
    const tStart = performance.now();
    f((check) => {
      const tEnd = performance.now();
      const duration = tEnd - tStart;
      
      const details = name + ': ' + '(' + duration + ') = ' + check;
    
      console.log(details);
    });
    
};

const imageDownload = (path, successCallback) => {
    let img = new Image();
    
    img.addEventListener("load", successCallback, false);
    
    img.src = path;
    
    return img;
};

TEST("TestImage", 
    TEST_F_ASYNC("testAsync", (done) => {
        let spyCountSuccess = 0;
        const expectedCountSuccess = spyCountSuccess + 1;
        
        const successCallback = () => {
            spyCountSuccess++;
            const actualCountSuccess = spyCountSuccess;
            const result = CHECK(actualCountSuccess, expectedCountSuccess)
            done(result);
        };
        const pathImage = 'https://i.imgur.com/Wutekcp.jpg';
        imageDownload(pathImage, successCallback);
        
    }),
    
    TEST_F('testSync', () => {
        return CHECK(1, 1);
    })

);