core: support local plugins from global Lighthouse

.gitignore

@@ -32,6 +32,7 @@ last-run-results.html
 !lighthouse-core/test/fixtures/artifacts/**/*.devtoolslog.json
 !lighthouse-core/test/fixtures/traces/**/*.trace.json
 !lighthouse-core/test/fixtures/traces/**/*.devtoolslog.json
+!lighthouse-core/test/fixtures/config/**/node_modules
 
 lighthouse-core/scripts/legacy-javascript/variants
 lighthouse-core/scripts/gcp-collection/gcp-data

lighthouse-core/config/config-helpers.js

@@ -176,6 +176,21 @@ function requireAudits(audits, configDir) {
  * @throws {Error}
  */
 function resolveModule(moduleIdentifier, configDir, category) {
+  // node_modules/
+  // |                                | Lighthouse globally installed | Lighthouse locally installed |
+  // |--------------------------------|-------------------------------|------------------------------|
+  // | in global                      |   1.                          |   1.                         |
+  // | current working directory      |   2.                          |   1.                         |
+  // | relative to config.js file     |   5.                          |   -                          |
+
+  // path to file
+  // |                                           | Lighthouse globally/locally installed |
+  // |-------------------------------------------|---------------------------------------|
+  // | absolute paths                            |   1.                                  |
+  // | relative to the current working directory |   3.                                  |
+  // | relative to the config.js file            |   4.                                  |
+
+  // 1.
   // First try straight `require()`. Unlikely to be specified relative to this
   // file, but adds support for Lighthouse modules from npm since
   // `require()` walks up parent directories looking inside any node_modules/
@@ -184,6 +199,18 @@ function resolveModule(moduleIdentifier, configDir, category) {
     return require.resolve(moduleIdentifier);
   } catch (e) {}
 
+  // 2.
+  // Lighthouse globally installed, node_modules/ in current working directoriy.
+  // ex: lighthouse https://test.com
+  //
+  // working directory/
+  //   |-- node_modules/
+  //   |-- package.json
+  try {
+    return require.resolve(moduleIdentifier, {paths: [process.cwd()]});
+  } catch (e) {}
+
+  // 3.
   // See if the module resolves relative to the current working directory.
   // Most useful to handle the case of invoking Lighthouse as a module, since
   // then the config is an object and so has no path.
@@ -202,14 +229,28 @@ function resolveModule(moduleIdentifier, configDir, category) {
     throw new Error(errorString);
   }
 
-  // Finally, try looking up relative to the config file path. Just like the
+  // 4.
+  // Try looking up relative to the config file path. Just like the
   // relative path passed to `require()` is found relative to the file it's
   // in, this allows module paths to be specified relative to the config file.
   const relativePath = path.resolve(configDir, moduleIdentifier);
   try {
     return require.resolve(relativePath);
   } catch (requireError) {}
 
+  // 5.
+  // Lighthouse globally installed, node_modules/ in config directoriy.
+  // ex: lighthouse https://test.com --config-path=./config/config.js
+  //
+  // working directory/
+  //   |-- config/
+  //     |-- node_modules/
+  //     |-- config.js
+  //     |-- package.json
+  try {
+    return require.resolve(moduleIdentifier, {paths: [relativePath]});
+  } catch (requireError) {}
+
   throw new Error(errorString + `
        ${relativePath}`);
 }

lighthouse-core/test/config/config-helpers-test.js

@@ -0,0 +1,76 @@
+/**
+ * @license Copyright 2020 The Lighthouse Authors. All Rights Reserved.
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.
+ */
+'use strict';
+
+/* eslint-env jest */
+
+const {resolveModule} = require('../../config/config-helpers.js');
+const assert = require('assert').strict;
+const path = require('path');
+
+jest.mock('process', () => ({
+  cwd: () => jest.fn(),
+}));
+
+describe('resolveModule', () => {
+  const configFixturePath = path.resolve(__dirname, '../fixtures/config');
+
+  beforeEach(() => {
+    process.cwd = jest.fn(() => configFixturePath);
+  });
+
+  it('lighthouse and plugins are installed in the same path', () => {
+    const pluginName = 'chrome-launcher';
+    const pathToPlugin = resolveModule(pluginName, null, 'plugin');
+    assert.equal(pathToPlugin, require.resolve(pluginName));
+  });
+
+  describe('plugin paths to a file', () => {
+    it('relative to the current working directory', () => {
+      const pluginName = 'lighthouse-plugin-config-helper';
+      const pathToPlugin = resolveModule(pluginName, null, 'plugin');
+      assert.equal(pathToPlugin, require.resolve(path.resolve(configFixturePath, pluginName)));
+    });
+
+    it('relative to the config path', () => {
+      const pluginName = 'lighthouse-plugin-config-helper';
+      const pathToPlugin = resolveModule(pluginName, configFixturePath, 'plugin');
+      assert.equal(pathToPlugin, require.resolve(path.resolve(configFixturePath, pluginName)));
+    });
+  });
+
+  describe('lighthouse and plugins are installed by npm', () => {
+    const pluginsDirectory = path.resolve(__dirname, '../fixtures/config/');
+
+    // working directory/
+    //   |-- node_modules/
+    //   |-- package.json
+    it('in current working directory', () => {
+      const pluginName = 'plugin-in-working-directory';
+      const pluginDir = `${pluginsDirectory}/node_modules/plugin-in-working-directory`;
+      process.cwd = jest.fn(() => pluginsDirectory);
+
+      const pathToPlugin = resolveModule(pluginName, null, 'plugin');
+
+      assert.equal(pathToPlugin, require.resolve(pluginName, {paths: [pluginDir]}));
+    });
+
+    // working directory/
+    //   |-- config directory/
+    //     |-- node_modules/
+    //     |-- config.js
+    //     |-- package.json
+    it('relative to the config path', () => {
+      const pluginName = 'plugin-in-config-directory';
+      const configDirectory = `${pluginsDirectory}/config`;
+      process.cwd = jest.fn(() => '/usr/bin/node');
+
+      const pathToPlugin = resolveModule(pluginName, configDirectory, 'plugin');
+
+      assert.equal(pathToPlugin, require.resolve(pluginName, {paths: [configDirectory]}));
+    });
+  });
+});

lighthouse-core/test/fixtures/config/config/config.js

@@ -0,0 +1,6 @@
+'use strict';
+
+module.exports = {
+  extends: 'lighthouse:default',
+  plugins: ['plugin-in-config-directory'],
+};

lighthouse-core/test/fixtures/config/lighthouse-plugin-config-helper/package.json

@@ -0,0 +1,5 @@
+{
+  "name": "lighthouse-plugin-config",
+  "private": true,
+  "main": "./plugin-config-helper.js"
+}

lighthouse-core/test/fixtures/config/lighthouse-plugin-config-helper/plugin-config-helper.js

@@ -0,0 +1,25 @@
+/**
+ * @license Copyright 2020 The Lighthouse Authors. All Rights Reserved.
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.
+ */
+'use strict';
+
+/** @type {LH.Config.Plugin} */
+module.exports = {
+  groups: {
+    'new-group': {
+      title: 'New Group',
+    },
+  },
+  audits: [
+    {path: 'redirects'},
+    {path: 'user-timings'},
+  ],
+  category: {
+    title: 'Config',
+    auditRefs: [
+      {id: 'redirects', weight: 1, group: 'new-group'},
+    ],
+  },
+};