Extend tests for --watch options

This commit adds two test cases to test the `--watch` option. We check
that touching a test file reruns the tests and we test that touching a
file that has a correct extensions reruns the test.

This commit adds `fs-extra` as a new dev dependency.

.eslintrc.yml

@@ -25,6 +25,8 @@ overrides:
       - bin/*
       - lib/cli/**/*.js
       - test/node-unit/**/*.js
+      - test/integration/options/watch.spec.js
+      - test/integration/helpers.js
       - lib/growl.js
     parserOptions:
       ecmaVersion: 6

package.json

@@ -550,6 +550,7 @@
     "eslint-plugin-prettier": "^3.0.1",
     "eslint-plugin-promise": "^4.0.1",
     "eslint-plugin-standard": "^4.0.0",
+    "fs-extra": "^8.0.1",
     "husky": "^1.3.1",
     "jsdoc": "^3.5.5",
     "karma": "^4.0.1",

test/integration/helpers.js

@@ -114,32 +114,37 @@ module.exports = {
     );
   },
   /**
-   * Invokes the mocha binary for the given fixture using the JSON reporter,
-   * returning the **raw** string output, as well as exit code.
+   * Invokes the mocha binary with the given arguments fixture using
+   * the JSON reporter. Returns the child process and a promise for the
+   * results of running the command. The result includes the **raw**
+   * string output, as well as exit code.
    *
    * By default, `STDERR` is ignored. Pass `{stdio: 'pipe'}` as `opts` if you
-   * want it.
-   * @param {string} fixturePath - Path from __dirname__
+   * want it as part of the result output.
+   *
    * @param {string[]} args - Array of args
-   * @param {Function} fn - Callback
    * @param {Object} [opts] - Opts for `spawn()`
-   * @returns {string} Raw output
+   * @returns {[ChildProcess|Promise<Result>]}
    */
-  runMochaJSONRaw: function(fixturePath, args, fn, opts) {
-    var path;
-
-    path = resolveFixturePath(fixturePath);
+  runMochaJSONRawAsync: function(args, opts) {
     args = args || [];
 
-    return invokeSubMocha(
-      args.concat(['--reporter', 'json', path]),
-      function(err, resRaw) {
-        if (err) return fn(err);
+    let childProcess;
+    const resultPromise = new Promise((resolve, reject) => {
+      childProcess = invokeSubMocha(
+        [...args, '--reporter', 'json'],
+        function(err, resRaw) {
+          if (err) {
+            reject(err);
+          } else {
+            resolve(resRaw);
+          }
+        },
+        opts
+      );
+    });
 
-        fn(null, resRaw);
-      },
-      opts
-    );
+    return [childProcess, resultPromise];
   },
 
   /**

test/integration/options/watch.spec.js

@@ -1,56 +1,173 @@
 'use strict';
 
-var helpers = require('../helpers');
-var runMochaJSONRaw = helpers.runMochaJSONRaw;
+const fs = require('fs-extra');
+const os = require('os');
+const path = require('path');
+const helpers = require('../helpers');
+const runMochaJSONRawAsync = helpers.runMochaJSONRawAsync;
+
+const sigintExitCode = 130;
 
 describe('--watch', function() {
-  var args = [];
+  describe('when enabled', function() {
+    this.timeout(10 * 1000);
+    this.slow(3000);
 
-  before(function() {
-    args = ['--watch'];
-  });
+    beforeEach(function() {
+      this.tempDir = fs.mkdtempSync(path.join(os.tmpdir(), 'mocha-'));
 
-  describe('when enabled', function() {
-    before(function() {
+      const fixtureSource = helpers.DEFAULT_FIXTURE;
+
+      this.testFile = path.join(this.tempDir, 'test.js');
+      fs.copySync(fixtureSource, this.testFile);
+    });
+
+    afterEach(function() {
+      if (this.tempDir) {
+        return fs.remove(this.tempDir);
+      }
+    });
+
+    it('should show the cursor and signal correct exit code, when watch process is terminated', function() {
       // Feature works but SIMULATING the signal (ctrl+c) via child process
       // does not work due to lack of POSIX signal compliance on Windows.
       if (process.platform === 'win32') {
         this.skip();
       }
-    });
 
-    it('should show the cursor and signal correct exit code, when watch process is terminated', function(done) {
-      this.timeout(0);
-      this.slow(3000);
-
-      var fixture = 'exit.fixture.js';
-      var spawnOpts = {stdio: 'pipe'};
-      var mocha = runMochaJSONRaw(
-        fixture,
-        args,
-        function postmortem(err, data) {
-          if (err) {
-            return done(err);
-          }
-
-          var expectedCloseCursor = '\u001b[?25h';
+      const [mocha, resultPromise] = runMochaJSONRawAsync([
+        helpers.DEFAULT_FIXTURE,
+        '--watch'
+      ]);
+
+      return sleep(1000)
+        .then(() => {
+          mocha.kill('SIGINT');
+          return resultPromise;
+        })
+        .then(data => {
+          const expectedCloseCursor = '\u001b[?25h';
           expect(data.output, 'to contain', expectedCloseCursor);
 
-          function exitStatusBySignal(sig) {
-            return 128 + sig;
-          }
+          expect(data.code, 'to be', sigintExitCode);
+        });
+    });
+
+    it('reruns test when watched test file is touched', function() {
+      const [mocha, outputPromise] = runMochaJSONWatchAsync([this.testFile], {
+        cwd: this.tempDir
+      });
 
-          var sigint = 2;
-          expect(data.code, 'to be', exitStatusBySignal(sigint));
-          done();
-        },
-        spawnOpts
+      return expect(
+        sleep(1000)
+          .then(() => {
+            touchFile(this.testFile);
+            return sleep(1000);
+          })
+          .then(() => {
+            mocha.kill('SIGINT');
+            return outputPromise;
+          }),
+        'when fulfilled',
+        'to have length',
+        2
       );
+    });
 
-      setTimeout(function() {
-        // Kill the child process
-        mocha.kill('SIGINT');
-      }, 1000);
+    it('reruns test when file matching extension is touched', function() {
+      const watchedFile = path.join(this.tempDir, 'file.xyz');
+      touchFile(watchedFile);
+      const [mocha, outputPromise] = runMochaJSONWatchAsync(
+        [this.testFile, '--extension', 'xyz,js'],
+        {
+          cwd: this.tempDir
+        }
+      );
+
+      return expect(
+        sleep(1000)
+          .then(() => {
+            touchFile(watchedFile);
+            return sleep(1000);
+          })
+          .then(() => {
+            mocha.kill('SIGINT');
+            return outputPromise;
+          }),
+        'when fulfilled',
+        'to have length',
+        2
+      );
+    });
+
+    it('ignores files in "node_modules" and ".git"', function() {
+      const nodeModulesFile = path.join(
+        this.tempDir,
+        'node_modules',
+        'file.xyz'
+      );
+      const gitFile = path.join(this.tempDir, '.git', 'file.xyz');
+
+      touchFile(gitFile);
+      touchFile(nodeModulesFile);
+
+      const [mocha, outputPromise] = runMochaJSONWatchAsync(
+        [this.testFile, '--extension', 'xyz,js'],
+        {
+          cwd: this.tempDir
+        }
+      );
+
+      return expect(
+        sleep(1000)
+          .then(() => {
+            touchFile(gitFile);
+            touchFile(nodeModulesFile);
+          })
+          .then(() => sleep(1000))
+          .then(() => {
+            mocha.kill('SIGINT');
+            return outputPromise;
+          }),
+        'when fulfilled',
+        'to have length',
+        1
+      );
     });
   });
 });
+
+/**
+ * Invokes the mocha binary with the `--watch` argument for the given fixture.
+ *
+ * Returns child process and a promise for the test results. The test results
+ * are an array of JSON objects generated by the JSON reporter.
+ */
+function runMochaJSONWatchAsync(args, spawnOpts) {
+  args = [...args, '--watch'];
+  const [mocha, mochaDone] = runMochaJSONRawAsync(args, spawnOpts);
+  const testResults = mochaDone.then(data => {
+    const testResults = data.output
+      // eslint-disable-next-line no-control-regex
+      .replace(/\u001b\[\?25./g, '')
+      .split('\u001b[2K')
+      .map(x => JSON.parse(x));
+    return testResults;
+  });
+  return [mocha, testResults];
+}
+
+/**
+ * Synchronously touch a file by appending a space to the end. Creates
+ * the file and all its parent directories if necessary.
+ */
+function touchFile(file) {
+  fs.ensureDirSync(path.dirname(file));
+  fs.appendFileSync(file, ' ');
+}
+
+function sleep(time) {
+  return new Promise(resolve => {
+    setTimeout(resolve, time);
+  });
+}