only 测试

¥only tests

如果 Node.js 以 --test-only 命令行选项启动，或者禁用测试隔离，则可以通过将 only 选项传递给应运行的测试来跳过除选定子集之外的所有测试。当设置了 only 选项的测试时，所有子测试也会运行。如果套件设置了 only 选项，则将运行该套件中的所有测试，除非它具有设置了 only 选项的后代，在这种情况下，仅运行这些测试。

¥If Node.js is started with the --test-only command-line option, or test isolation is disabled, it is possible to skip all tests except for a selected subset by passing the only option to the tests that should run. When a test with the only option is set, all subtests are also run. If a suite has the only option set, all tests within the suite are run, unless it has descendants with the only option set, in which case only those tests are run.

在 test()/it() 中使用 subtests 时，需要使用 only 选项标记所有祖级测试，以仅运行选定的测试子集。

¥When using subtests within a test()/it(), it is required to mark all ancestor tests with the only option to run only a selected subset of tests.

测试上下文的 runOnly() 方法可用于在子测试级别实现相同的行为。未执行的测试将从测试运行器输出中省略。

¥The test context's runOnly() method can be used to implement the same behavior at the subtest level. Tests that are not executed are omitted from the test runner output.

// Assume Node.js is run with the --test-only command-line option.
// The suite's 'only' option is set, so these tests are run.
test('this test is run', { only: true }, async (t) => {
  // Within this test, all subtests are run by default.
  await t.test('running subtest');

  // The test context can be updated to run subtests with the 'only' option.
  t.runOnly(true);
  await t.test('this subtest is now skipped');
  await t.test('this subtest is run', { only: true });

  // Switch the context back to execute all tests.
  t.runOnly(false);
  await t.test('this subtest is now run');

  // Explicitly do not run these tests.
  await t.test('skipped subtest 3', { only: false });
  await t.test('skipped subtest 4', { skip: true });
});

// The 'only' option is not set, so this test is skipped.
test('this test is not run', () => {
  // This code is not run.
  throw new Error('fail');
});

describe('a suite', () => {
  // The 'only' option is set, so this test is run.
  it('this test is run', { only: true }, () => {
    // This code is run.
  });

  it('this test is not run', () => {
    // This code is not run.
    throw new Error('fail');
  });
});

describe.only('a suite', () => {
  // The 'only' option is set, so this test is run.
  it('this test is run', () => {
    // This code is run.
  });

  it('this test is run', () => {
    // This code is run.
  });
}); 拷贝