diff --git a/index.js b/index.js
index 5254885dfb3d2..9b09868c3c790 100644
--- a/index.js
+++ b/index.js
@@ -16,12 +16,16 @@
 
 const {helper} = require('./lib/helper');
 const api = require('./lib/api');
+const {Page} = require('./lib/Page');
 for (const className in api) {
   // Puppeteer-web excludes certain classes from bundle, e.g. BrowserFetcher.
   if (typeof api[className] === 'function')
     helper.installAsyncStackHooks(api[className]);
 }
 
+// Expose alias for deprecated method.
+Page.prototype.emulateMedia = Page.prototype.emulateMediaType;
+
 // If node does not support async await, use the compiled version.
 const Puppeteer = require('./lib/Puppeteer');
 const packageJson = require('./package.json');
diff --git a/package.json b/package.json
index 8c9bebdce7e96..4b54d7375141a 100644
--- a/package.json
+++ b/package.json
@@ -58,6 +58,7 @@
     "cross-env": "^5.0.5",
     "eslint": "^6.8.0",
     "esprima": "^4.0.0",
+    "expect": "^25.2.7",
     "jpeg-js": "^0.3.4",
     "minimist": "^1.2.0",
     "ncp": "^2.0.0",
diff --git a/src/Page.js b/src/Page.js
index 9be58789a2ba9..81ff80483c9d7 100644
--- a/src/Page.js
+++ b/src/Page.js
@@ -1146,9 +1146,6 @@ class Page extends EventEmitter {
   }
 }
 
-// Expose alias for deprecated method.
-Page.prototype.emulateMedia = Page.prototype.emulateMediaType;
-
 /**
  * @typedef {Object} PDFOptions
  * @property {number=} scale
diff --git a/test/puppeteer.spec.js b/test/puppeteer.spec.js
index dcc7788b4ac85..a6fa47d435ebf 100644
--- a/test/puppeteer.spec.js
+++ b/test/puppeteer.spec.js
@@ -16,8 +16,9 @@
 const fs = require('fs');
 const path = require('path');
 const rm = require('rimraf').sync;
-const GoldenUtils = require('./golden-utils');
-const {Matchers} = require('../utils/testrunner/');
+const utils = require('./utils');
+
+const expect = require('expect');
 
 const YELLOW_COLOR = '\x1b[33m';
 const RESET_COLOR = '\x1b[0m';
@@ -59,13 +60,13 @@ module.exports.addTests = ({testRunner, product, puppeteerPath}) => {
   }
 
   const suffix = FFOX ? 'firefox' : product.toLowerCase();
+
   const GOLDEN_DIR = path.join(__dirname, 'golden-' + suffix);
   const OUTPUT_DIR = path.join(__dirname, 'output-' + suffix);
   if (fs.existsSync(OUTPUT_DIR))
     rm(OUTPUT_DIR);
-  const {expect} = new Matchers({
-    toBeGolden: GoldenUtils.compare.bind(null, GOLDEN_DIR, OUTPUT_DIR)
-  });
+
+  utils.extendExpectWithToBeGolden(GOLDEN_DIR, OUTPUT_DIR);
 
   const testOptions = {
     testRunner,
diff --git a/test/target.spec.js b/test/target.spec.js
index 23d65fd41e7ad..dd0d81bb2f0e7 100644
--- a/test/target.spec.js
+++ b/test/target.spec.js
@@ -27,8 +27,8 @@ module.exports.addTests = function({testRunner, expect, puppeteer}) {
       // The pages will be the testing page and the original newtab page
       const targets = browser.targets();
       expect(targets.some(target => target.type() === 'page' &&
-        target.url() === 'about:blank')).toBeTruthy('Missing blank page');
-      expect(targets.some(target => target.type() === 'browser')).toBeTruthy('Missing browser target');
+        target.url() === 'about:blank')).toBeTruthy();
+      expect(targets.some(target => target.type() === 'browser')).toBeTruthy();
     });
     it('Browser.pages should return all of the pages', async({page, server, context}) => {
       // The pages will be the testing page
diff --git a/test/utils.js b/test/utils.js
index d95a087da9ff9..4ed56e6027fbc 100644
--- a/test/utils.js
+++ b/test/utils.js
@@ -16,6 +16,8 @@
 
 const fs = require('fs');
 const path = require('path');
+const expect = require('expect');
+const GoldenUtils = require('./golden-utils');
 const {FlakinessDashboard} = require('../utils/flakiness-dashboard');
 const PROJECT_ROOT = fs.existsSync(path.join(__dirname, '..', 'package.json')) ? path.join(__dirname, '..') : path.join(__dirname, '..', '..');
 
@@ -72,6 +74,19 @@ const utils = module.exports = {
     });
   },
 
+  extendExpectWithToBeGolden: function(goldenDir, outputDir) {
+    expect.extend({
+      toBeGolden: (testScreenshot, goldenFilePath) => {
+        const result = GoldenUtils.compare(goldenDir, outputDir, testScreenshot, goldenFilePath);
+
+        return {
+          message: () => result.message,
+          pass: result.pass
+        };
+      }
+    });
+  },
+
   /**
    * @return {string}
    */
diff --git a/utils/browser/test.js b/utils/browser/test.js
index 2e238924b1cfe..2f10acf7b3678 100644
--- a/utils/browser/test.js
+++ b/utils/browser/test.js
@@ -2,7 +2,8 @@ const path = require('path');
 const fs = require('fs');
 const puppeteer = require('../..');
 const {TestServer} = require('../testserver/');
-const {TestRunner, Reporter, Matchers} = require('../testrunner/');
+const {TestRunner, Reporter} = require('../testrunner/');
+const expect = require('expect');
 
 const puppeteerWebPath = path.join(__dirname, 'puppeteer-web.js');
 if (!fs.existsSync(puppeteerWebPath))
@@ -13,7 +14,6 @@ const testRunner = new TestRunner();
 const {describe, fdescribe, xdescribe} = testRunner;
 const {it, xit, fit} = testRunner;
 const {afterAll, beforeAll, afterEach, beforeEach} = testRunner;
-const {expect} = new Matchers();
 
 beforeAll(async state => {
   const assetsPath = path.join(__dirname, '..', '..', 'test', 'assets');
diff --git a/utils/doclint/check_public_api/test/test.js b/utils/doclint/check_public_api/test/test.js
index 0f35ef362d47b..bdf1a67f7f7ff 100644
--- a/utils/doclint/check_public_api/test/test.js
+++ b/utils/doclint/check_public_api/test/test.js
@@ -22,7 +22,10 @@ const mdBuilder = require('../MDBuilder');
 const jsBuilder = require('../JSBuilder');
 const GoldenUtils = require('../../../../test/golden-utils');
 
-const {TestRunner, Reporter, Matchers}  = require('../../../testrunner/');
+const testUtils = require('../../../../test/utils')
+
+const {TestRunner, Reporter}  = require('../../../testrunner/');
+const expect = require('expect')
 const runner = new TestRunner();
 const reporter = new Reporter(runner);
 
@@ -60,9 +63,7 @@ runner.run();
 
 async function testLint(state, test) {
   const dirPath = path.join(__dirname, test.name);
-  const {expect} = new Matchers({
-    toBeGolden: GoldenUtils.compare.bind(null, dirPath, dirPath)
-  });
+  testUtils.extendExpectWithToBeGolden(dirPath, dirPath)
 
   const mdSources = await Source.readdir(dirPath, '.md');
   const jsSources = await Source.readdir(dirPath, '.js');
@@ -73,9 +74,8 @@ async function testLint(state, test) {
 
 async function testMDBuilder(state, test) {
   const dirPath = path.join(__dirname, test.name);
-  const {expect} = new Matchers({
-    toBeGolden: GoldenUtils.compare.bind(null, dirPath, dirPath)
-  });
+  testUtils.extendExpectWithToBeGolden(dirPath, dirPath)
+
   const sources = await Source.readdir(dirPath, '.md');
   const {documentation} = await mdBuilder(page, sources);
   expect(serialize(documentation)).toBeGolden('result.txt');
@@ -83,9 +83,9 @@ async function testMDBuilder(state, test) {
 
 async function testJSBuilder(state, test) {
   const dirPath = path.join(__dirname, test.name);
-  const {expect} = new Matchers({
-    toBeGolden: GoldenUtils.compare.bind(null, dirPath, dirPath)
-  });
+  testUtils.extendExpectWithToBeGolden(dirPath, dirPath)
+
+
   const sources = await Source.readdir(dirPath, '.js');
   const {documentation} = await jsBuilder(sources);
   expect(serialize(documentation)).toBeGolden('result.txt');
@@ -124,4 +124,4 @@ function serializeType(type) {
     name: type.name,
     properties: type.properties.length ? type.properties.map(serializeMember) : undefined
   }
-}
\ No newline at end of file
+}
diff --git a/utils/doclint/preprocessor/test.js b/utils/doclint/preprocessor/test.js
index 5d6be0ccec15e..d9ba46e000b80 100644
--- a/utils/doclint/preprocessor/test.js
+++ b/utils/doclint/preprocessor/test.js
@@ -16,14 +16,14 @@
 
 const {runCommands, ensureReleasedAPILinks} = require('.');
 const Source = require('../Source');
-const {TestRunner, Reporter, Matchers}  = require('../../testrunner/');
+const expect = require('expect');
+const {TestRunner, Reporter}  = require('../../testrunner/');
 const runner = new TestRunner();
 new Reporter(runner);
 
 const {describe, xdescribe, fdescribe} = runner;
 const {it, fit, xit} = runner;
 const {beforeAll, beforeEach, afterAll, afterEach} = runner;
-const {expect} = new Matchers();
 
 describe('ensureReleasedAPILinks', function() {
   it('should work with non-release version', function() {
diff --git a/utils/testrunner/Matchers.js b/utils/testrunner/Matchers.js
deleted file mode 100644
index 000751d43c83f..0000000000000
--- a/utils/testrunner/Matchers.js
+++ /dev/null
@@ -1,130 +0,0 @@
-/**
- * Copyright 2017 Google Inc. 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.
- */
-
-module.exports = class Matchers {
-  constructor(customMatchers = {}) {
-    this._matchers = {};
-    Object.assign(this._matchers, DefaultMatchers);
-    Object.assign(this._matchers, customMatchers);
-    this.expect = this.expect.bind(this);
-  }
-
-  addMatcher(name, matcher) {
-    this._matchers[name] = matcher;
-  }
-
-  expect(value) {
-    return new Expect(value, this._matchers);
-  }
-};
-
-class Expect {
-  constructor(value, matchers) {
-    this.not = {};
-    this.not.not = this;
-    for (const matcherName of Object.keys(matchers)) {
-      const matcher = matchers[matcherName];
-      this[matcherName] = applyMatcher.bind(null, matcherName, matcher, false /* inverse */, value);
-      this.not[matcherName] = applyMatcher.bind(null, matcherName, matcher, true /* inverse */, value);
-    }
-
-    function applyMatcher(matcherName, matcher, inverse, value, ...args) {
-      const result = matcher.call(null, value, ...args);
-      const message = `expect.${inverse ? 'not.' : ''}${matcherName} failed` + (result.message ? `: ${result.message}` : '');
-      if (result.pass === inverse)
-        throw new Error(message);
-    }
-  }
-}
-
-const DefaultMatchers = {
-  toBe: function(value, other, message) {
-    message = message || `${value} == ${other}`;
-    return { pass: value === other, message };
-  },
-
-  toBeFalsy: function(value, message) {
-    message = message || `${value}`;
-    return { pass: !value, message };
-  },
-
-  toBeTruthy: function(value, message) {
-    message = message || `${value}`;
-    return { pass: !!value, message };
-  },
-
-  toBeGreaterThan: function(value, other, message) {
-    message = message || `${value} > ${other}`;
-    return { pass: value > other, message };
-  },
-
-  toBeGreaterThanOrEqual: function(value, other, message) {
-    message = message || `${value} >= ${other}`;
-    return { pass: value >= other, message };
-  },
-
-  toBeLessThan: function(value, other, message) {
-    message = message || `${value} < ${other}`;
-    return { pass: value < other, message };
-  },
-
-  toBeLessThanOrEqual: function(value, other, message) {
-    message = message || `${value} <= ${other}`;
-    return { pass: value <= other, message };
-  },
-
-  toBeNull: function(value, message) {
-    message = message || `${value} == null`;
-    return { pass: value === null, message };
-  },
-
-  toContain: function(value, other, message) {
-    message = message || `${value} ⊇ ${other}`;
-    return { pass: value.includes(other), message };
-  },
-
-  toEqual: function(value, other, message) {
-    const valueJson = stringify(value);
-    const otherJson = stringify(other);
-    message = message || `\n${valueJson} ≈ ${otherJson}`;
-    return { pass: valueJson === otherJson, message };
-  },
-
-  toBeCloseTo: function(value, other, precision, message) {
-    return {
-      pass: Math.abs(value - other) < Math.pow(10, -precision),
-      message
-    };
-  },
-
-  toBeInstanceOf: function(value, other, message) {
-    message = message || `${value.constructor.name} instanceof ${other.name}`;
-    return { pass: value instanceof other, message };
-  },
-};
-
-function stringify(value) {
-  function stabilize(key, object) {
-    if (typeof object !== 'object' || object === undefined || object === null)
-      return object;
-    const result = {};
-    for (const key of Object.keys(object).sort())
-      result[key] = object[key];
-    return result;
-  }
-
-  return JSON.stringify(stabilize(null, value), stabilize, 2);
-}
diff --git a/utils/testrunner/README.md b/utils/testrunner/README.md
index b3ca075fdc89c..5ae83cf15d16f 100644
--- a/utils/testrunner/README.md
+++ b/utils/testrunner/README.md
@@ -7,6 +7,7 @@ This test runner is used internally by Puppeteer to test Puppeteer itself.
 - supports async/await
 - modular
 - well-isolated state per execution thread
+- uses the `expect` library from `npm` for assertions.
 
 ### Installation
 
@@ -23,15 +24,14 @@ node test.js
 ```
 
 ```js
-const {TestRunner, Reporter, Matchers} = require('@pptr/testrunner');
+const {TestRunner, Reporter} = require('@pptr/testrunner');
+const expect = require('expect')
 
 // Runner holds and runs all the tests
 const runner = new TestRunner({
   parallel: 2, // run 2 parallel threads
   timeout: 1000, // setup timeout of 1 second per test
 });
-// Simple expect-like matchers
-const {expect} = new Matchers();
 
 // Extract jasmine-like DSL into the global namespace
 const {describe, xdescribe, fdescribe} = runner;
diff --git a/utils/testrunner/examples/fail.js b/utils/testrunner/examples/fail.js
index 6e2cd75ac419f..588f0a4feb451 100644
--- a/utils/testrunner/examples/fail.js
+++ b/utils/testrunner/examples/fail.js
@@ -14,11 +14,11 @@
  * limitations under the License.
  */
 
-const {TestRunner, Reporter, Matchers} = require('..');
+const {TestRunner, Reporter} = require('..');
 
 const runner = new TestRunner();
 const reporter = new Reporter(runner);
-const {expect} = new Matchers();
+const expect = require('expect');
 
 const {describe, xdescribe, fdescribe} = runner;
 const {it, fit, xit} = runner;
diff --git a/utils/testrunner/examples/hookfail.js b/utils/testrunner/examples/hookfail.js
index 038f58c47f2fd..18922505fa3ba 100644
--- a/utils/testrunner/examples/hookfail.js
+++ b/utils/testrunner/examples/hookfail.js
@@ -14,11 +14,11 @@
  * limitations under the License.
  */
 
-const {TestRunner, Reporter, Matchers} = require('..');
+const {TestRunner, Reporter} = require('..');
 
 const runner = new TestRunner();
 const reporter = new Reporter(runner);
-const {expect} = new Matchers();
+const expect = require('expect');
 
 const {describe, xdescribe, fdescribe} = runner;
 const {it, fit, xit} = runner;
diff --git a/utils/testrunner/examples/hooktimeout.js b/utils/testrunner/examples/hooktimeout.js
index 525f2b7c8adf0..cf57d6b00fc3c 100644
--- a/utils/testrunner/examples/hooktimeout.js
+++ b/utils/testrunner/examples/hooktimeout.js
@@ -14,11 +14,11 @@
  * limitations under the License.
  */
 
-const {TestRunner, Reporter, Matchers} = require('..');
+const {TestRunner, Reporter} = require('..');
 
 const runner = new TestRunner({ timeout: 100 });
 const reporter = new Reporter(runner);
-const {expect} = new Matchers();
+const expect = require('expect');
 
 const {describe, xdescribe, fdescribe} = runner;
 const {it, fit, xit} = runner;
diff --git a/utils/testrunner/index.js b/utils/testrunner/index.js
index 998ea3d150033..3bd964619a341 100644
--- a/utils/testrunner/index.js
+++ b/utils/testrunner/index.js
@@ -16,6 +16,5 @@
 
 const TestRunner = require('./TestRunner');
 const Reporter = require('./Reporter');
-const Matchers = require('./Matchers');
 
-module.exports = { TestRunner, Reporter, Matchers };
+module.exports = { TestRunner, Reporter};
diff --git a/utils/testrunner/test/test.js b/utils/testrunner/test/test.js
index d4f6b461a39ce..1e3eaf90d7ff1 100644
--- a/utils/testrunner/test/test.js
+++ b/utils/testrunner/test/test.js
@@ -1,7 +1,7 @@
-const {TestRunner, Matchers, Reporter} = require('..');
+const {TestRunner, Reporter} = require('..');
 
 const testRunner = new TestRunner();
-const {expect} = new Matchers();
+const expect = require('expect');
 
 require('./testrunner.spec.js').addTests({testRunner, expect});