Chrome DevTools MCP

/** * @license * Copyright 2025 Google LLC * SPDX-License-Identifier: Apache-2.0 */ import assert from 'node:assert'; import {afterEach, describe, it} from 'node:test'; import sinon from 'sinon'; import { extractUrlLikeFromDevToolsTitle, urlsEqual, mapIssueToMessageObject, UniverseManager, } from '../src/DevtoolsUtils.js'; import {ISSUE_UTILS} from '../src/issue-descriptions.js'; import {DevTools} from '../src/third_party/index.js'; import type {Browser, Target} from '../src/third_party/index.js'; import { getMockBrowser, getMockPage, mockListener, withBrowser, } from './utils.js'; describe('extractUrlFromDevToolsTitle', () => { it('deals with no trailing /', () => { assert.strictEqual( extractUrlLikeFromDevToolsTitle('DevTools - example.com'), 'example.com', ); }); it('deals with a trailing /', () => { assert.strictEqual( extractUrlLikeFromDevToolsTitle('DevTools - example.com/'), 'example.com/', ); }); it('deals with www', () => { assert.strictEqual( extractUrlLikeFromDevToolsTitle('DevTools - www.example.com/'), 'www.example.com/', ); }); it('deals with complex url', () => { assert.strictEqual( extractUrlLikeFromDevToolsTitle( 'DevTools - www.example.com/path.html?a=b#3', ), 'www.example.com/path.html?a=b#3', ); }); }); describe('urlsEqual', () => { it('ignores trailing slashes', () => { assert.strictEqual( urlsEqual('https://google.com/', 'https://google.com'), true, ); }); it('ignores www', () => { assert.strictEqual( urlsEqual('https://google.com/', 'https://www.google.com'), true, ); }); it('ignores protocols', () => { assert.strictEqual( urlsEqual('https://google.com/', 'http://www.google.com'), true, ); }); it('does not ignore other subdomains', () => { assert.strictEqual( urlsEqual('https://google.com/', 'https://photos.google.com'), false, ); }); it('ignores hash', () => { assert.strictEqual( urlsEqual('https://google.com/#', 'http://www.google.com'), true, ); assert.strictEqual( urlsEqual('https://google.com/#21', 'http://www.google.com#12'), true, ); }); }); describe('mapIssueToMessageObject', () => { const mockDescription = { file: 'mock-issue.md', substitutions: new Map([['PLACEHOLDER_VALUE', 'substitution value']]), links: [ {link: 'http://example.com/learnmore', linkTitle: 'Learn more'}, { link: 'http://example.com/another-learnmore', linkTitle: 'Learn more 2', }, ], }; afterEach(() => { sinon.restore(); }); it('maps aggregated issue with substituted description', () => { const mockAggregatedIssue = sinon.createStubInstance( DevTools.AggregatedIssue, ); mockAggregatedIssue.getDescription.returns(mockDescription); mockAggregatedIssue.getAggregatedIssuesCount.returns(1); const getIssueDescriptionStub = sinon.stub( ISSUE_UTILS, 'getIssueDescription', ); getIssueDescriptionStub .withArgs('mock-issue.md') .returns( '# Mock Issue Title\n\nThis is a mock issue description with a {PLACEHOLDER_VALUE}.', ); const result = mapIssueToMessageObject(mockAggregatedIssue); const expected = { type: 'issue', item: mockAggregatedIssue, message: 'Mock Issue Title', count: 1, description: '# Mock Issue Title\n\nThis is a mock issue description with a substitution value.', }; assert.deepStrictEqual(result, expected); }); it('returns null for the issue with no description', () => { const mockAggregatedIssue = sinon.createStubInstance( DevTools.AggregatedIssue, ); mockAggregatedIssue.getDescription.returns(null); const result = mapIssueToMessageObject(mockAggregatedIssue); assert.equal(result, null); }); it('returns null if there is no desciption file', () => { const mockAggregatedIssue = sinon.createStubInstance( DevTools.AggregatedIssue, ); mockAggregatedIssue.getDescription.returns(mockDescription); mockAggregatedIssue.getAggregatedIssuesCount.returns(1); const getIssueDescriptionStub = sinon.stub( ISSUE_UTILS, 'getIssueDescription', ); getIssueDescriptionStub.withArgs('mock-issue.md').returns(null); const result = mapIssueToMessageObject(mockAggregatedIssue); assert.equal(result, null); }); it("returns null if can't parse the title", () => { const mockAggregatedIssue = sinon.createStubInstance( DevTools.AggregatedIssue, ); mockAggregatedIssue.getDescription.returns(mockDescription); mockAggregatedIssue.getAggregatedIssuesCount.returns(1); const getIssueDescriptionStub = sinon.stub( ISSUE_UTILS, 'getIssueDescription', ); getIssueDescriptionStub .withArgs('mock-issue.md') .returns('No title test {PLACEHOLDER_VALUE}'); assert.deepStrictEqual(mapIssueToMessageObject(mockAggregatedIssue), null); }); it('returns null if devtools utill function throws an error', () => { const mockAggregatedIssue = sinon.createStubInstance( DevTools.AggregatedIssue, ); mockAggregatedIssue.getDescription.returns(mockDescription); mockAggregatedIssue.getAggregatedIssuesCount.returns(1); const getIssueDescriptionStub = sinon.stub( ISSUE_UTILS, 'getIssueDescription', ); // An error will be thrown if placeholder doesn't start from PLACEHOLDER_ getIssueDescriptionStub .withArgs('mock-issue.md') .returns('No title test {WRONG_PLACEHOLDER}'); assert.deepStrictEqual(mapIssueToMessageObject(mockAggregatedIssue), null); }); }); describe('UniverseManager', () => { it('calls the factory for existing pages', async () => { const browser = getMockBrowser(); const factory = sinon.stub().resolves({}); const manager = new UniverseManager(browser, factory); await manager.init(await browser.pages()); const page = (await browser.pages())[0]; sinon.assert.calledOnceWithExactly(factory, page); }); it('calls the factory only once for the same page', async () => { const browser = { ...mockListener(), } as unknown as Browser; // eslint-disable-next-line @typescript-eslint/no-empty-function const factory = sinon.stub().returns(new Promise(() => {})); // Don't resolve. const manager = new UniverseManager(browser, factory); await manager.init([]); sinon.assert.notCalled(factory); const page = getMockPage(); browser.emit('targetcreated', { page: () => Promise.resolve(page), } as Target); browser.emit('targetcreated', { page: () => Promise.resolve(page), } as Target); await new Promise(r => setTimeout(r, 0)); // One event loop tick for the micro task queue to run. sinon.assert.calledOnceWithExactly(factory, page); }); it('works with a real browser', async () => { await withBrowser(async (browser, page) => { const manager = new UniverseManager(browser); await manager.init([page]); assert.notStrictEqual(manager.get(page), null); }); }); it('ignores pauses', async () => { await withBrowser(async (browser, page) => { const manager = new UniverseManager(browser); await manager.init([page]); const targetUniverse = manager.get(page); assert.ok(targetUniverse); const model = targetUniverse.target.model(DevTools.DebuggerModel); assert.ok(model); const pausedSpy = sinon.stub(); model.addEventListener('DebuggerPaused' as any, pausedSpy); // eslint-disable-line const result = await page.evaluate('debugger; 1 + 1'); assert.strictEqual(result, 2); sinon.assert.notCalled(pausedSpy); }); }); });