test/style: refactor test-task to make it more readable

Gruntfile.js

@@ -263,6 +263,8 @@ module.exports = function(grunt) {
 
   this.registerTask('amd', ['babel:amd', 'requirejs']);
 
+  this.registerTask('test', ['test:bin', 'test:cov', 'test:check-cov']);
+
   grunt.registerTask('bench', ['metrics']);
 
   if (process.env.SAUCE_USERNAME) {

tasks/.eslintrc.js

@@ -7,6 +7,8 @@ module.exports = {
   },
   rules: {
     'no-process-env': 'off',
-    'prefer-const': 'warn'
+    'prefer-const': 'warn',
+    'compat/compat': 'off',
+    'dot-notation': ['error', { allowKeywords: true }]
   }
 };

tasks/parser.js

@@ -29,7 +29,7 @@ module.exports = function(grunt) {
       ]
         .map(grunt.file.read)
         .join('');
-      grunt.file['delete']('handlebars.js');
+      grunt.file.delete('handlebars.js');
 
       grunt.file.write('lib/handlebars/compiler/parser.js', src);
       grunt.log.writeln('Parser "lib/handlebars/compiler/parser.js" created.');

tasks/test-bin.js

@@ -0,0 +1,55 @@
+const childProcess = require('child_process'),
+  fs = require('fs'),
+  os = require('os'),
+  expect = require('chai').expect,
+  util = require('util');
+
+const readFile = util.promisify(fs.readFile);
+const execFile = util.promisify(childProcess.execFile);
+
+module.exports = function(grunt) {
+  grunt.registerTask(
+    'test:bin',
+    wrapAsync(async function() {
+      const { stdout } = await execFileWithWin32Fallback('./bin/handlebars', [
+        '-a',
+        'spec/artifacts/empty.handlebars'
+      ]);
+
+      const expectedOutput = await readFile(
+        './spec/expected/empty.amd.js',
+        'utf-8'
+      );
+
+      const normalizedOutput = normalizeCrlf(stdout);
+      const normalizedExpectedOutput = normalizeCrlf(expectedOutput);
+      expect(normalizedOutput).to.equal(normalizedExpectedOutput);
+    })
+  );
+
+  async function execFileWithWin32Fallback(command, args) {
+    // On Windows, the executable handlebars.js file cannot be run directly
+    if (os.platform() === 'win32') {
+      args.unshift(command);
+      command = process.argv[0];
+    }
+    return execFile(command, args, { encoding: 'utf-8' });
+  }
+
+  function normalizeCrlf(string) {
+    if (string != null) {
+      return string.replace(/\r\n/g, '\n');
+    }
+    return string;
+  }
+
+  function wrapAsync(asyncFunction) {
+    return function() {
+      asyncFunction()
+        .catch(error => {
+          grunt.fatal(error);
+        })
+        .finally(this.async());
+    };
+  }
+};

tasks/test-mocha.js

@@ -0,0 +1,66 @@
+const childProcess = require('child_process');
+
+module.exports = function(grunt) {
+  grunt.registerTask(
+    'test:mocha',
+    promiseBasedTask(async () => forkAndWait('./spec/env/runner'))
+  );
+
+  grunt.registerTask(
+    'test:cov',
+    promiseBasedTask(async () =>
+      forkAndWait(
+        'node_modules/istanbul/lib/cli.js',
+        'cover',
+        '--source-map',
+        '--',
+        './spec/env/runner.js'
+      )
+    )
+  );
+
+  grunt.registerTask(
+    'test:min',
+    promiseBasedTask(async () => forkAndWait('./spec/env/runner', '--min'))
+  );
+
+  grunt.registerTask(
+    'test:check-cov',
+    promiseBasedTask(() =>
+      forkAndWait(
+        'node_modules/istanbul/lib/cli.js',
+        'check-coverage',
+        '--statements',
+        '100',
+        '--functions',
+        '100',
+        '--branches',
+        '100',
+        '--lines 100'
+      )
+    )
+  );
+
+  function promiseBasedTask(asyncFunction) {
+    return function() {
+      asyncFunction()
+        .catch(error => {
+          grunt.fatal(error);
+        })
+        .finally(this.async());
+    };
+  }
+
+  async function forkAndWait(command, ...args) {
+    return new Promise((resolve, reject) => {
+      const child = childProcess.fork(command, args, { stdio: 'inherit' });
+      child.on('close', code => {
+        if (code !== 0) {
+          reject(new Error(`Child process failed with exit-code ${code}`));
+        }
+      });
+    });
+  }
+
+  grunt.registerTask('test', ['test:bin', 'test:cov', 'test:check-cov']);
+};