fix(cli): add proper extends support for package.json files

lib/cli/config.js

@@ -11,7 +11,6 @@ const fs = require('fs');
 const path = require('path');
 const debug = require('debug')('mocha:cli:config');
 const findUp = require('find-up');
-const yargs = require('yargs/yargs');
 const {createUnparsableFileError} = require('../errors');
 const utils = require('../utils');
 
@@ -77,12 +76,6 @@ exports.loadConfig = filepath => {
     } else {
       config = parsers.json(filepath);
     }
-
-    const {$0, ...options} = yargs(config._, path.dirname(filepath))
-      .parserConfiguration(require('./options').YARGS_PARSER_CONFIG)
-      .config(config).argv;
-
-    config = options;
   } catch (err) {
     throw createUnparsableFileError(
       `Unable to read/parse ${filepath}: ${err}`,

lib/cli/options.js

@@ -8,7 +8,9 @@
  */
 
 const fs = require('fs');
+const path = require('path');
 const ansi = require('ansi-colors');
+const yargs = require('yargs/yargs');
 const yargsParser = require('yargs-parser');
 const {types, aliases} = require('./run-option-metadata');
 const {ONE_AND_DONE_ARGS} = require('./one-and-dones');
@@ -159,7 +161,7 @@ const parse = (args = [], defaultValues = {}, ...configObjects) => {
 const loadRc = (args = {}) => {
   if (args.config !== false) {
     const config = args.config || findConfig();
-    return config ? loadConfig(config) : {};
+    return config ? loadRcFile(loadConfig(config), config) : {};
   }
 };
 
@@ -185,7 +187,7 @@ const loadPkgRc = (args = {}) => {
       const pkg = JSON.parse(fs.readFileSync(filepath, 'utf8'));
       if (pkg.mocha) {
         debug('`mocha` prop of package.json parsed: %O', pkg.mocha);
-        result = pkg.mocha;
+        result = loadRcFile(pkg.mocha, filepath);
       } else {
         debug('no config found in %s', filepath);
       }
@@ -204,6 +206,20 @@ const loadPkgRc = (args = {}) => {
 
 module.exports.loadPkgRc = loadPkgRc;
 
+/**
+ * Loads the inherited configuration of the rc file located at the specified {@linkcode filePath}.
+ *
+ * @param {Object} config - The parsed configuration of the rc file.
+ * @param {string} filePath - The name of the file containing the parsed configuration.
+ */
+const loadRcFile = (config, filePath) => {
+  const {$0, ...options} = yargs(config._, path.dirname(filePath))
+    .parserConfiguration(configuration)
+    .config(config).argv;
+
+  return options;
+};
+
 /**
  * Priority list:
  *

test/integration/options.spec.js

@@ -45,6 +45,7 @@ describe('options', function () {
 
   it('Should support extended options using package.json', function () {
     var extended = loadOptions([
+      '--no-config',
       '--package',
       path.join(workspaceDir, 'package-lock.json')
     ]);