watch.spec.js

'use strict';

const fs = require('fs-extra');
const path = require('path');
const {
  copyFixture,
  runMochaWatchJSONAsync,
  sleep,
  runMochaWatchAsync,
  touchFile,
  replaceFileContents,
  createTempDir,
  DEFAULT_FIXTURE
} = require('../helpers');

describe('--watch', function() {
  describe('when enabled', function() {
    /**
     * @type {string}
     */
    let tempDir;
    /**
     * @type {import('../helpers').RemoveTempDirCallback}
     */
    let cleanup;

    this.slow(5000);

    beforeEach(async function() {
      const {dirpath, removeTempDir} = await createTempDir();
      tempDir = dirpath;
      cleanup = removeTempDir;
    });

    afterEach(function() {
      cleanup();
    });

    it('reruns test when watched test file is touched', function() {
      const testFile = path.join(tempDir, 'test.js');
      copyFixture(DEFAULT_FIXTURE, testFile);

      return runMochaWatchJSONAsync([testFile], tempDir, () => {
        touchFile(testFile);
      }).then(results => {
        expect(results, 'to have length', 2);
      });
    });

    it('reruns test when watched test file crashes', function() {
      const testFile = path.join(tempDir, 'test.js');
      copyFixture(DEFAULT_FIXTURE, testFile);

      replaceFileContents(testFile, 'done();', 'done((;');

      return runMochaWatchJSONAsync([testFile], tempDir, () => {
        replaceFileContents(testFile, 'done((;', 'done();');
      }).then(results => {
        expect(results, 'to have length', 1);
      });
    });

    describe('when in parallel mode', function() {
      it('reruns test when watched test file is touched', function() {
        const testFile = path.join(tempDir, 'test.js');
        copyFixture(DEFAULT_FIXTURE, testFile);

        return runMochaWatchJSONAsync(['--parallel', testFile], tempDir, () => {
          touchFile(testFile);
        }).then(results => {
          expect(results, 'to have length', 2);
        });
      });

      it('reruns test when watched test file is crashed', function() {
        const testFile = path.join(tempDir, 'test.js');
        copyFixture(DEFAULT_FIXTURE, testFile);

        replaceFileContents(testFile, 'done();', 'done((;');

        return runMochaWatchJSONAsync([testFile], tempDir, () => {
          replaceFileContents(testFile, 'done((;', 'done();');
        }).then(results => {
          expect(results, 'to have length', 1);
        });
      });
    });

    it('reruns test when file matching --watch-files changes', function() {
      const testFile = path.join(tempDir, 'test.js');
      copyFixture(DEFAULT_FIXTURE, testFile);

      const watchedFile = path.join(tempDir, 'dir/file.xyz');
      touchFile(watchedFile);

      return runMochaWatchJSONAsync(
        [testFile, '--watch-files', 'dir/*.xyz'],
        tempDir,
        () => {
          touchFile(watchedFile);
        }
      ).then(results => {
        expect(results.length, 'to equal', 2);
      });
    });

    it('reruns test when file matching --watch-files is added', function() {
      const testFile = path.join(tempDir, 'test.js');
      copyFixture(DEFAULT_FIXTURE, testFile);

      const watchedFile = path.join(tempDir, 'lib/file.xyz');
      return runMochaWatchJSONAsync(
        [testFile, '--watch-files', '**/*.xyz'],
        tempDir,
        () => {
          touchFile(watchedFile);
        }
      ).then(results => {
        expect(results, 'to have length', 2);
      });
    });

    it('reruns test when file matching --watch-files is removed', function() {
      const testFile = path.join(tempDir, 'test.js');
      copyFixture(DEFAULT_FIXTURE, testFile);

      const watchedFile = path.join(tempDir, 'lib/file.xyz');
      touchFile(watchedFile);

      return runMochaWatchJSONAsync(
        [testFile, '--watch-files', 'lib/**/*.xyz'],
        tempDir,
        () => {
          fs.removeSync(watchedFile);
        }
      ).then(results => {
        expect(results, 'to have length', 2);
      });
    });

    it('does not rerun test when file not matching --watch-files is changed', function() {
      const testFile = path.join(tempDir, 'test.js');
      copyFixture(DEFAULT_FIXTURE, testFile);

      const watchedFile = path.join(tempDir, 'dir/file.js');
      touchFile(watchedFile);

      return runMochaWatchJSONAsync(
        [testFile, '--watch-files', 'dir/*.xyz'],
        tempDir,
        () => {
          touchFile(watchedFile);
        }
      ).then(results => {
        expect(results.length, 'to equal', 1);
      });
    });

    it('picks up new test files when they are added', function() {
      const testFile = path.join(tempDir, 'test/a.js');
      copyFixture(DEFAULT_FIXTURE, testFile);

      return runMochaWatchJSONAsync(
        ['test/**/*.js', '--watch-files', 'test/**/*.js'],
        tempDir,
        () => {
          const addedTestFile = path.join(tempDir, 'test/b.js');
          copyFixture('passing', addedTestFile);
        }
      ).then(results => {
        expect(results, 'to have length', 2);
        expect(results[0].passes, 'to have length', 1);
        expect(results[1].passes, 'to have length', 3);
      });
    });

    it('reruns test when file matching --extension is changed', function() {
      const testFile = path.join(tempDir, 'test.js');
      copyFixture(DEFAULT_FIXTURE, testFile);

      const watchedFile = path.join(tempDir, 'file.xyz');
      touchFile(watchedFile);

      return runMochaWatchJSONAsync(
        [testFile, '--extension', 'xyz,js'],
        tempDir,
        () => {
          touchFile(watchedFile);
        }
      ).then(results => {
        expect(results, 'to have length', 2);
      });
    });

    it('reruns when "rs\\n" typed', function() {
      const testFile = path.join(tempDir, 'test.js');
      copyFixture(DEFAULT_FIXTURE, testFile);

      return runMochaWatchJSONAsync([testFile], tempDir, mochaProcess => {
        mochaProcess.stdin.write('rs\n');
      }).then(results => {
        expect(results, 'to have length', 2);
      });
    });

    it('reruns test when file starting with . and matching --extension is changed', function() {
      const testFile = path.join(tempDir, 'test.js');
      copyFixture(DEFAULT_FIXTURE, testFile);

      const watchedFile = path.join(tempDir, '.file.xyz');
      touchFile(watchedFile);

      return runMochaWatchJSONAsync(
        [testFile, '--extension', 'xyz,js'],
        tempDir,
        () => {
          touchFile(watchedFile);
        }
      ).then(results => {
        expect(results, 'to have length', 2);
      });
    });

    it('ignores files in "node_modules" and ".git" by default', function() {
      const testFile = path.join(tempDir, 'test.js');
      copyFixture(DEFAULT_FIXTURE, testFile);

      const nodeModulesFile = path.join(tempDir, 'node_modules', 'file.xyz');
      const gitFile = path.join(tempDir, '.git', 'file.xyz');

      touchFile(gitFile);
      touchFile(nodeModulesFile);

      return runMochaWatchJSONAsync(
        [testFile, '--extension', 'xyz,js'],
        tempDir,
        () => {
          touchFile(gitFile);
          touchFile(nodeModulesFile);
        }
      ).then(results => {
        expect(results, 'to have length', 1);
      });
    });

    it('ignores files matching --watch-ignore', function() {
      const testFile = path.join(tempDir, 'test.js');
      copyFixture(DEFAULT_FIXTURE, testFile);

      const watchedFile = path.join(tempDir, 'dir/file-to-ignore.xyz');
      touchFile(watchedFile);

      return runMochaWatchJSONAsync(
        [
          testFile,
          '--watch-files',
          'dir/*.xyz',
          '--watch-ignore',
          'dir/*ignore*'
        ],
        tempDir,
        () => {
          touchFile(watchedFile);
        }
      ).then(results => {
        expect(results.length, 'to equal', 1);
      });
    });

    it('reloads test files when they change', function() {
      const testFile = path.join(tempDir, 'test.js');
      copyFixture('options/watch/test-file-change', testFile);

      return runMochaWatchJSONAsync(
        [testFile, '--watch-files', '**/*.js'],
        tempDir,
        () => {
          replaceFileContents(
            testFile,
            'testShouldFail = true',
            'testShouldFail = false'
          );
        }
      ).then(results => {
        expect(results, 'to have length', 2);
        expect(results[0].passes, 'to have length', 0);
        expect(results[0].failures, 'to have length', 1);
        expect(results[1].passes, 'to have length', 1);
        expect(results[1].failures, 'to have length', 0);
      });
    });

    it('reloads test dependencies when they change', function() {
      const testFile = path.join(tempDir, 'test.js');
      copyFixture('options/watch/test-with-dependency', testFile);

      const dependency = path.join(tempDir, 'lib', 'dependency.js');
      copyFixture('options/watch/dependency', dependency);

      return runMochaWatchJSONAsync(
        [testFile, '--watch-files', 'lib/**/*.js'],
        tempDir,
        () => {
          replaceFileContents(
            dependency,
            'module.exports.testShouldFail = false',
            'module.exports.testShouldFail = true'
          );
        }
      ).then(results => {
        expect(results, 'to have length', 2);
        expect(results[0].passes, 'to have length', 1);
        expect(results[0].failures, 'to have length', 0);
        expect(results[1].passes, 'to have length', 0);
        expect(results[1].failures, 'to have length', 1);
      });
    });

    // Regression test for https://github.com/mochajs/mocha/issues/2027
    it('respects --fgrep on re-runs', async function() {
      const testFile = path.join(tempDir, 'test.js');
      copyFixture('options/grep', testFile);

      return expect(
        runMochaWatchJSONAsync([testFile, '--fgrep', 'match'], tempDir, () => {
          touchFile(testFile);
        }),
        'when fulfilled',
        'to satisfy',
        {
          length: 2,
          0: {tests: expect.it('to have length', 2)},
          1: {tests: expect.it('to have length', 2)}
        }
      );
    });

    describe('with required hooks', function() {
      /**
       * Helper for setting up hook tests
       *
       * @param {string} hookName name of hook to test
       * @return {function}
       */
      function setupHookTest(hookName) {
        return function() {
          const testFile = path.join(tempDir, 'test.js');
          const hookFile = path.join(tempDir, 'hook.js');

          copyFixture('__default__', testFile);
          copyFixture('options/watch/hook', hookFile);

          replaceFileContents(hookFile, '<hook>', hookName);

          return runMochaWatchJSONAsync(
            [testFile, '--require', hookFile],
            tempDir,
            () => {
              touchFile(testFile);
            }
          ).then(results => {
            expect(results.length, 'to equal', 2);
            expect(results[0].failures, 'to have length', 1);
            expect(results[1].failures, 'to have length', 1);
          });
        };
      }

      it('mochaHooks.beforeAll runs as expected', setupHookTest('beforeAll'));
      it('mochaHooks.beforeEach runs as expected', setupHookTest('beforeEach'));
      it('mochaHooks.afterAll runs as expected', setupHookTest('afterAll'));
      it('mochaHooks.afterEach runs as expected', setupHookTest('afterEach'));
    });

    it('should not leak event listeners', function() {
      this.timeout(20000);
      const testFile = path.join(tempDir, 'test.js');
      copyFixture(DEFAULT_FIXTURE, testFile);

      return expect(
        runMochaWatchAsync(
          [testFile],
          {cwd: tempDir, stdio: 'pipe'},
          async () => {
            // we want to cause _n + 1_ reruns, which should cause the warning
            // to occur if the listeners aren't properly destroyed
            const iterations = new Array(process.getMaxListeners() + 1);
            // eslint-disable-next-line no-unused-vars
            for await (const _ of iterations) {
              touchFile(testFile);
              await sleep(1000);
            }
          }
        ),
        'when fulfilled',
        'to satisfy',
        {
          output: expect.it('not to match', /MaxListenersExceededWarning/)
        }
      );
    });
  });
});