freeCodeCamp/curriculum/challenges/chinese/06-quality-assurance/quality-assurance-and-testing-with-chai/test-if-a-variable-or-function-is-defined.md

id	title	challengeType	forumTopicId	dashedName
587d824b367417b2b2512c47	测试变量或函数是否已定义	2	301602	test-if-a-variable-or-function-is-defined

--description--

请注意，本项目在这个 Replit 项目的基础上进行开发。你也可以从 GitHub 上克隆。

--instructions--

在 tests/1_unit-tests.js 中，Basic Assertions 套件中标注为 #2 的测试下，修改每个 assert 为 assert.isDefined() 或 assert.isUndefined()，通过测试（结果应为 true）。 不要修改传给断言的参数。

--hints--

应通过所有测试。

(getUserInput) =>
  $.get(getUserInput('url') + '/_api/get-tests?type=unit&n=1').then(
    (data) => {
      assert.equal(data.state, 'passed');
    },
    (xhr) => {
      throw new Error(xhr.responseText);
    }
  );

应该为第一个断言选择正确的方法：isDefined 或 isUndefined。

(getUserInput) =>
  $.get(getUserInput('url') + '/_api/get-tests?type=unit&n=1').then(
    (data) => {
      assert.equal(
        data.assertions[0].method,
        'isDefined',
        'Null is not undefined'
      );
    },
    (xhr) => {
      throw new Error(xhr.responseText);
    }
  );

应该为第二个断言选择正确的方法：isDefined 或 isUndefined。

(getUserInput) =>
  $.get(getUserInput('url') + '/_api/get-tests?type=unit&n=1').then(
    (data) => {
      assert.equal(
        data.assertions[1].method,
        'isUndefined',
        'Undefined is undefined'
      );
    },
    (xhr) => {
      throw new Error(xhr.responseText);
    }
  );

应该为第三个断言选择正确的方法：isDefined 或 isUndefined。

(getUserInput) =>
  $.get(getUserInput('url') + '/_api/get-tests?type=unit&n=1').then(
    (data) => {
      assert.equal(
        data.assertions[2].method,
        'isDefined',
        'A string is not undefined'
      );
    },
    (xhr) => {
      throw new Error(xhr.responseText);
    }
  );

--solutions--

/**
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*/