QUnit：每个方法进行一次测试，有多个断言，还是每个方法进行多个测试？

Question

我决定为我的下一个 javascript 项目开始 TDD，并且我使用 QUnit 进行单元测试。我对单元测试完全陌生，从未用任何语言做过。下面是我的一个模块的示例，加上一个针对 find 方法的测试，该方法尝试涵盖此方法将遇到的所有场景：

module("TextSwapper", {
    setup: function() { 
        this.str = 'When you first start off trying to solve a problem, the first solutions you come up with are very complex, and most people stop there. But if you keep going, and live with the problem and peel more layers of the onion off, you can often times arrive at some very elegant and simple solutions.';

        this.ts = new TextSwapper();
        ok(this.ts, 'The TextSwapper was created successfully');

        this.textarea = document.createElement('textarea');
        this.textarea.value = this.str;
        document.body.appendChild(this.textarea);
    },
    teardown: function() {
            document.body.removeChild(this.textarea);
    }
});

test("find()", function() {
    equal(this.ts.find('When'), false, "Check it fails gracefully when no input has been set.");
    this.textarea.focus();
    equal(this.ts.find('When'), true, "Check it finds 'When' if the textarea has focus but no input has been set.");

    this.ts.setInput(this.textarea);
    this.ts.find('When');
    equal(window.getSelection().toString(), 'When', 'The word \'When\' should be highlighted');
    equal(this.ts.found[0][0], 'When', 'The word \'When\' should be in the found array');

    this.ts.find('you');
    equal(window.getSelection().toString(), 'you', 'The word \'you\' should be highlighted');
    equal(this.ts.found[1][0], 'you', 'The word \'you\' should be in the found array');
    equal(this.ts.found.length, 4 ,'Should have found 4 you\'s');

    this.ts.find('bill');
    equal(this.ts.found.length, 0, 'Check that nothing was found for \'bill\'');

    this.ts.find('[a-z]*ee[a-z]*');
    equal(window.getSelection().toString(), 'keep', 'The word \'keep\' should be highlighted');
    equal(this.ts.found[1][0], 'peel', 'The word \'peel\' should be in the found array');
    equal(this.ts.found.length, 2 ,'Should have found 2 for [a-z]*ee[a-z]*');

});

我的问题是我是否以正确的方式处理此问题？我的测试中是否有太多断言？我的测试是否应该分解为更小的测试？我一直在 stackoverflow 上阅读 TDD，现在读到的一些东西让我觉得我做错了。

Answer 1

如果您使用 TDD，那么您应该为每种测试方法使用一个断言。

以下链接很好地解释了用一种方法测试所有内容时可能遇到的问题：单元测试 它可以更轻松地在代码中引入隐藏的错误。

Answer 2

如果你能找到 Bob Martin 的《Clean Code》的副本，他在单元测试的章节中讨论了这个问题。他的观点是“每个测试一个断言”可能有点尴尬（他在书中给出了一个很好的例子），而他更喜欢“每个测试一个概念”。因此，如果您觉得多个断言密切相关并且分开会很烦人，请继续使用它们。