diff --git a/.eslintignore b/.eslintignore
index f75e5368e1..6097957a12 100644
--- a/.eslintignore
+++ b/.eslintignore
@@ -15,3 +15,4 @@ src/webkit/protocol.ts
 utils/generate_types/overrides.d.ts
 utils/generate_types/test/test.ts
 test/
+test-runner/
\ No newline at end of file
diff --git a/.github/workflows/auto_roll.yml b/.github/workflows/auto_roll.yml
index c9b58f4028..5ba8eadad9 100644
--- a/.github/workflows/auto_roll.yml
+++ b/.github/workflows/auto_roll.yml
@@ -27,7 +27,7 @@ jobs:
     # XVFB-RUN merges both STDOUT and STDERR, whereas we need only STDERR
     # Wrap `npm run` in a subshell to redirect STDERR to file.
     # Enable core dumps in the subshell.
-    - run: xvfb-run --auto-servernum --server-args="-screen 0 1280x960x24" -- bash -c "ulimit -c unlimited && node test/runner/cli test/ --jobs=1 --forbid-only --timeout=30000"
+    - run: xvfb-run --auto-servernum --server-args="-screen 0 1280x960x24" -- bash -c "ulimit -c unlimited && node test-runner/cli test/ --jobs=1 --forbid-only --timeout=30000"
       env:
         BROWSER: ${{ matrix.browser }}
         DEBUG: "pw:*,-pw:wrapped*,-pw:test*"
diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 54839cc4eb..8581ebcc08 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -37,7 +37,7 @@ jobs:
     # XVFB-RUN merges both STDOUT and STDERR, whereas we need only STDERR
     # Wrap `npm run` in a subshell to redirect STDERR to file.
     # Enable core dumps in the subshell.
-    - run: xvfb-run --auto-servernum --server-args="-screen 0 1280x960x24" -- bash -c "ulimit -c unlimited && node test/runner/cli test/ --jobs=1 --forbid-only --timeout=30000 && npm run coverage"
+    - run: xvfb-run --auto-servernum --server-args="-screen 0 1280x960x24" -- bash -c "ulimit -c unlimited && node test-runner/cli test/ --jobs=1 --forbid-only --timeout=30000 && npm run coverage"
       env:
         BROWSER: ${{ matrix.browser }}
         DEBUG: "pw:*,-pw:wrapped*,-pw:test*"
@@ -68,7 +68,7 @@ jobs:
     - uses: microsoft/playwright-github-action@v1
     - run: npm ci
     - run: npm run build
-    - run: node test/runner/cli test/ --jobs=1 --forbid-only --timeout=30000
+    - run: node test-runner/cli test/ --jobs=1 --forbid-only --timeout=30000
       env:
         BROWSER: ${{ matrix.browser }}
         DEBUG: "pw:*,-pw:wrapped*,-pw:test*"
@@ -102,7 +102,7 @@ jobs:
     - uses: microsoft/playwright-github-action@v1
     - run: npm ci
     - run: npm run build
-    - run: node test/runner/cli test/ --jobs=1 --forbid-only --timeout=30000
+    - run: node test-runner/cli test/ --jobs=1 --forbid-only --timeout=30000
       shell: bash
       env:
         BROWSER: ${{ matrix.browser }}
@@ -159,7 +159,7 @@ jobs:
     # XVFB-RUN merges both STDOUT and STDERR, whereas we need only STDERR
     # Wrap `npm run` in a subshell to redirect STDERR to file.
     # Enable core dumps in the subshell.
-    - run: xvfb-run --auto-servernum --server-args="-screen 0 1280x960x24" -- bash -c "ulimit -c unlimited && node test/runner/cli test/ --jobs=1 --forbid-only --timeout=30000"
+    - run: xvfb-run --auto-servernum --server-args="-screen 0 1280x960x24" -- bash -c "ulimit -c unlimited && node test-runner/cli test/ --jobs=1 --forbid-only --timeout=30000"
       if: ${{ always() }}
       env:
         BROWSER: ${{ matrix.browser }}
@@ -197,7 +197,7 @@ jobs:
     # XVFB-RUN merges both STDOUT and STDERR, whereas we need only STDERR
     # Wrap `npm run` in a subshell to redirect STDERR to file.
     # Enable core dumps in the subshell.
-    - run: xvfb-run --auto-servernum --server-args="-screen 0 1280x960x24" -- bash -c "ulimit -c unlimited && node test/runner/cli test/ --jobs=1 --forbid-only --timeout=30000"
+    - run: xvfb-run --auto-servernum --server-args="-screen 0 1280x960x24" -- bash -c "ulimit -c unlimited && node test-runner/cli test/ --jobs=1 --forbid-only --timeout=30000"
       env:
         BROWSER: ${{ matrix.browser }}
         DEBUG: "pw:*,-pw:wrapped*,-pw:test*"
diff --git a/package.json b/package.json
index d7adb95a34..2f54b47209 100644
--- a/package.json
+++ b/package.json
@@ -9,19 +9,19 @@
     "node": ">=10.15.0"
   },
   "scripts": {
-    "ctest": "cross-env BROWSER=chromium node test/runner/cli test/",
-    "ftest": "cross-env BROWSER=firefox node test/runner/cli test/",
-    "wtest": "cross-env BROWSER=webkit node test/runner/cli test/",
-    "test": "node test/runner/cli test/",
+    "ctest": "cross-env BROWSER=chromium node test-runner/cli test/",
+    "ftest": "cross-env BROWSER=firefox node test-runner/cli test/",
+    "wtest": "cross-env BROWSER=webkit node test-runner/cli test/",
+    "test": "node test-runner/cli test/",
     "eslint": "[ \"$CI\" = true ] && eslint --quiet -f codeframe --ext js,ts ./src || eslint --ext js,ts ./src",
     "tsc": "tsc -p .",
     "tsc-installer": "tsc -p ./src/install/tsconfig.json",
     "doc": "node utils/doclint/cli.js",
-    "test-infra": "node test/runner/cli utils/doclint/check_public_api/test/test.js && node test/runner/cli utils/doclint/preprocessor/test.js",
+    "test-infra": "node test-runner/cli utils/doclint/check_public_api/test/test.js && node test-runner/cli utils/doclint/preprocessor/test.js",
     "lint": "npm run eslint && npm run tsc && npm run doc && npm run check-deps && npm run generate-channels && npm run test-types && npm run test-infra",
     "clean": "rimraf lib && rimraf types",
     "prepare": "node install-from-github.js",
-    "build": "node utils/runWebpack.js --mode='development' && tsc -p . && npm run generate-types",
+    "build": "node utils/runWebpack.js --mode='development' && tsc -p . && npm run build-testrunner && npm run generate-types",
     "watch": "node utils/watch.js",
     "test-types": "npm run generate-types && npx -p typescript@3.7.5 tsc -p utils/generate_types/test/tsconfig.json && npm run typecheck-tests",
     "generate-types": "node utils/generate_types/",
@@ -30,7 +30,8 @@
     "roll-browser": "node utils/roll_browser.js",
     "coverage": "node test/checkCoverage.js",
     "check-deps": "node utils/check_deps.js",
-    "build-driver": "pkg --public --targets node12-linux-x64,node12-macos-x64,node12-win-x64 --out-path=drivers packages/playwright-driver/main.js"
+    "build-driver": "pkg --public --targets node12-linux-x64,node12-macos-x64,node12-win-x64 --out-path=drivers packages/playwright-driver/main.js",
+    "build-testrunner": "tsc -p test-runner"
   },
   "author": {
     "name": "Microsoft Corporation"
diff --git a/test-runner/cli.js b/test-runner/cli.js
new file mode 100644
index 0000000000..822d1f86c8
--- /dev/null
+++ b/test-runner/cli.js
@@ -0,0 +1,2 @@
+#!/usr/bin/env node
+module.exports = require('./lib/cli')
\ No newline at end of file
diff --git a/test-runner/package.json b/test-runner/package.json
new file mode 100644
index 0000000000..6631bf9378
--- /dev/null
+++ b/test-runner/package.json
@@ -0,0 +1,8 @@
+{
+  "name": "test-runner",
+  "version": "0.0.7",
+  "bin": {
+    "test-runner": "./cli.js"
+  },
+  "main": "./lib/index.js"
+}
\ No newline at end of file
diff --git a/test/runner/GoldenUtils.js b/test-runner/src/GoldenUtils.js
similarity index 96%
rename from test/runner/GoldenUtils.js
rename to test-runner/src/GoldenUtils.js
index 837150aa8b..752ccb92d6 100644
--- a/test/runner/GoldenUtils.js
+++ b/test-runner/src/GoldenUtils.js
@@ -42,7 +42,7 @@ const GoldenComparators = {
  * @param {?Object} actualBuffer
  * @param {!Buffer} expectedBuffer
  * @param {!string} mimeType
- * @return {?{diff: (!Object:undefined), errorMessage: (string|undefined)}}
+ * @return {?{diff?: Object, errorMessage?: string}}
  */
 function compareImages(actualBuffer, expectedBuffer, mimeType, config = {}) {
   if (!actualBuffer || !(actualBuffer instanceof Buffer))
@@ -63,7 +63,7 @@ function compareImages(actualBuffer, expectedBuffer, mimeType, config = {}) {
 /**
  * @param {?Object} actual
  * @param {!Buffer} expectedBuffer
- * @return {?{diff: (!Object:undefined), errorMessage: (string|undefined)}}
+ * @return {?{diff?: Object, errorMessage?: string, diffExtension?: string}}
  */
 function compareText(actual, expectedBuffer) {
   if (typeof actual !== 'string')
@@ -85,8 +85,8 @@ function compareText(actual, expectedBuffer) {
 
 /**
  * @param {?Object} actual
- * @param {string} path
- * @return {!{pass: boolean, message: (undefined|string)}}
+ * @param {string} name
+ * @return {!{pass: boolean, message?: string}}
  */
 function compare(actual, name, options) {
   const { relativeTestFile, snapshotDir, outputDir, updateSnapshots } = options;
diff --git a/test-runner/src/builtin.fixtures.ts b/test-runner/src/builtin.fixtures.ts
new file mode 100644
index 0000000000..f3dd317981
--- /dev/null
+++ b/test-runner/src/builtin.fixtures.ts
@@ -0,0 +1,72 @@
+/**
+ * Copyright Microsoft Corporation. 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.
+ */
+
+import os from 'os';
+import path from 'path';
+import {promisify} from 'util';
+import fs from 'fs';
+import rimraf from 'rimraf';
+import {registerFixture} from './fixtures';
+
+
+declare global {
+  type DescribeFunction = ((name: string, inner: () => void) => void) & {
+    fail(condition: boolean): DescribeFunction;
+    skip(condition: boolean): DescribeFunction;
+    slow(): DescribeFunction;
+    repeat(n: number): DescribeFunction;
+  };
+
+  type ItFunction<STATE> = ((name: string, inner: (state: STATE) => Promise<void>) => void) & {
+    fail(condition: boolean): ItFunction<STATE>;
+    skip(condition: boolean): ItFunction<STATE>;
+    slow(): ItFunction<STATE>;
+    repeat(n: number): ItFunction<STATE>;
+  };
+
+  const describe: DescribeFunction;
+  const fdescribe: DescribeFunction;
+  const xdescribe: DescribeFunction;
+  const it: ItFunction<TestState & WorkerState & FixtureParameters>;
+  const fit: ItFunction<TestState & WorkerState & FixtureParameters>;
+  const dit: ItFunction<TestState & WorkerState & FixtureParameters>;
+  const xit: ItFunction<TestState & WorkerState & FixtureParameters>;
+
+  const beforeEach: (inner: (state: TestState & WorkerState & FixtureParameters) => Promise<void>) => void;
+  const afterEach: (inner: (state: TestState & WorkerState & FixtureParameters) => Promise<void>) => void;
+  const beforeAll: (inner: (state: WorkerState & FixtureParameters) => Promise<void>) => void;
+  const afterAll: (inner: (state: WorkerState & FixtureParameters) => Promise<void>) => void;
+}
+
+const mkdtempAsync = promisify(fs.mkdtemp);
+const removeFolderAsync = promisify(rimraf);
+
+declare global {
+  interface FixtureParameters {
+    parallelIndex: number;
+  }
+  interface TestState {
+    tmpDir: string;
+  }
+}
+
+export {parameters, registerFixture, registerWorkerFixture, registerParameter} from './fixtures';
+
+registerFixture('tmpDir', async ({}, test) => {
+  const tmpDir = await mkdtempAsync(path.join(os.tmpdir(), 'playwright-test-'));
+  await test(tmpDir);
+  await removeFolderAsync(tmpDir).catch(e => {});
+});
diff --git a/test/runner/cli.js b/test-runner/src/cli.js
similarity index 93%
rename from test/runner/cli.js
rename to test-runner/src/cli.js
index 5cafb15adb..f168416c0b 100644
--- a/test/runner/cli.js
+++ b/test-runner/src/cli.js
@@ -25,21 +25,21 @@ let beforeFunction;
 let afterFunction;
 let matrix = {};
 
-global.before = (fn => beforeFunction = fn);
-global.after = (fn => afterFunction = fn);
-global.matrix = (m => matrix = m);
+global['before'] = (fn => beforeFunction = fn);
+global['after'] = (fn => afterFunction = fn);
+global['matrix'] = (m => matrix = m);
 
 program
-  .version('Version ' + require('../../package.json').version)
+  .version('Version ' + /** @type {any} */ (require)('../package.json').version)
   .option('--forbid-only', 'Fail if exclusive test(s) encountered', false)
   .option('-g, --grep <grep>', 'Only run tests matching this string or regexp', '.*')
-  .option('-j, --jobs <jobs>', 'Number of concurrent jobs for --parallel; use 1 to run in serial, default: (number of CPU cores / 2)', Math.ceil(require('os').cpus().length / 2))
+  .option('-j, --jobs <jobs>', 'Number of concurrent jobs for --parallel; use 1 to run in serial, default: (number of CPU cores / 2)', Math.ceil(require('os').cpus().length / 2).toString())
   .option('--reporter <reporter>', 'Specify reporter to use', '')
   .option('--trial-run', 'Only collect the matching tests and report them as passing')
   .option('--quiet', 'Suppress stdio', false)
   .option('--debug', 'Run tests in-process for debugging', false)
   .option('--output <outputDir>', 'Folder for output artifacts, default: test-results', path.join(process.cwd(), 'test-results'))
-  .option('--timeout <timeout>', 'Specify test timeout threshold (in milliseconds), default: 10000', 10000)
+  .option('--timeout <timeout>', 'Specify test timeout threshold (in milliseconds), default: 10000', '10000')
   .option('-u, --update-snapshots', 'Use this flag to re-record every snapshot that fails during this test run')
   .action(async (command) => {
     // Collect files]
@@ -101,7 +101,7 @@ program
     try {
       if (beforeFunction)
         await beforeFunction();
-      await runner.run(files);
+      await runner.run();
       await runner.stop();
     } finally {
       if (afterFunction)
diff --git a/test/runner/dotReporter.js b/test-runner/src/dotReporter.js
similarity index 98%
rename from test/runner/dotReporter.js
rename to test-runner/src/dotReporter.js
index f39eaa8d26..5489fbc610 100644
--- a/test/runner/dotReporter.js
+++ b/test-runner/src/dotReporter.js
@@ -69,7 +69,7 @@ class DotReporter extends Base {
       this.failures.forEach((failure, index) => {
         const relativePath = path.relative(process.cwd(), failure.file);
         const header = `  ${index +1}. ${terminalLink(relativePath, `file://${os.hostname()}${failure.file}`)} › ${failure.title}`;
-        console.log(colors.bold.red(header));
+        console.log(colors.bold(colors.red(header)));
         const stack = failure.err.stack;
         if (stack) {
           console.log('');
diff --git a/test/runner/fixtures.js b/test-runner/src/fixtures.ts
similarity index 65%
rename from test/runner/fixtures.js
rename to test-runner/src/fixtures.ts
index 64b15a5667..5ad5ab2dba 100644
--- a/test/runner/fixtures.js
+++ b/test-runner/src/fixtures.ts
@@ -14,21 +14,45 @@
  * limitations under the License.
  */
 
-const debug = require('debug');
+import debug from 'debug';
+
+declare global {
+  interface WorkerState {
+  }
+
+  interface TestState {
+  }
+
+  interface FixtureParameters {
+  }
+}
 
 const registrations = new Map();
 const registrationsByFile = new Map();
-let parameters = {};
-const parameterRegistrations = new Map();
+export let parameters: FixtureParameters = {} as FixtureParameters;
+export const parameterRegistrations = new Map();
 
-function setParameters(params) {
+export function setParameters(params: any) {
   parameters = Object.assign(parameters, params);
   for (const name of Object.keys(params))
-    registerWorkerFixture(name, async ({}, test) => await test(parameters[name]));
+    registerWorkerFixture(name as keyof WorkerState, async ({}, test) => await test(parameters[name] as never));
 }
 
+
 class Fixture {
-  constructor(pool, name, scope, fn) {
+  pool: FixturePool;
+  name: string;
+  scope: any;
+  fn: any;
+  deps: any;
+  usages: Set<unknown>;
+  hasGeneratorValue: boolean;
+  value: any;
+  _teardownFenceCallback: (value?: unknown) => void;
+  _tearDownComplete: any;
+  _setup: boolean;
+  _teardown: any;
+  constructor(pool: FixturePool, name: string, scope: any, fn: any) {
     this.pool = pool;
     this.name = name;
     this.scope = scope;
@@ -50,16 +74,16 @@ class Fixture {
     const params = {};
     for (const n of this.deps)
       params[n] = this.pool.instances.get(n).value;
-    let setupFenceFulfill;
-    let setupFenceReject;
+    let setupFenceFulfill: { (): void; (value?: unknown): void; };
+    let setupFenceReject: { (arg0: any): any; (reason?: any): void; };
     const setupFence = new Promise((f, r) => { setupFenceFulfill = f; setupFenceReject = r; });
     const teardownFence = new Promise(f => this._teardownFenceCallback = f);
     debug('pw:test:hook')(`setup "${this.name}"`);
-    this._tearDownComplete = this.fn(params, async value => {
+    this._tearDownComplete = this.fn(params, async (value: any) => {
       this.value = value;
       setupFenceFulfill();
       await teardownFence;
-    }).catch(e => setupFenceReject(e));
+    }).catch((e: any) => setupFenceReject(e));
     await setupFence;
     this._setup = true;
   }
@@ -85,12 +109,13 @@ class Fixture {
   }
 }
 
-class FixturePool {
+export class FixturePool {
+  instances: Map<any, any>;
   constructor() {
     this.instances = new Map();
   }
 
-  async setupFixture(name) {
+  async setupFixture(name: string) {
     let fixture = this.instances.get(name);
     if (fixture)
       return fixture;
@@ -104,14 +129,14 @@ class FixturePool {
     return fixture;
   }
 
-  async teardownScope(scope) {
+  async teardownScope(scope: string) {
     for (const [name, fixture] of this.instances) {
       if (fixture.scope === scope)
         await fixture.teardown();
     }
   }
 
-  async resolveParametersAndRun(fn) {
+  async resolveParametersAndRun(fn: (arg0: {}) => any) {
     const names = fixtureParameterNames(fn);
     for (const name of names)
       await this.setupFixture(name);
@@ -121,7 +146,7 @@ class FixturePool {
     return fn(params);
   }
 
-  wrapTestCallback(callback) {
+  wrapTestCallback(callback: any) {
     if (!callback)
       return callback;
     return async() => {
@@ -134,9 +159,9 @@ class FixturePool {
   }
 }
 
-function fixturesForCallback(callback) {
-  const names = new Set();
-  const visit  = (callback) => {
+export function fixturesForCallback(callback: any): string[] {
+  const names = new Set<string>();
+  const visit  = (callback: any) => {
     for (const name of fixtureParameterNames(callback)) {
       if (name in names)
         continue;
@@ -154,26 +179,28 @@ function fixturesForCallback(callback) {
   return result;
 }
 
-function fixtureParameterNames(fn) {
+function fixtureParameterNames(fn: { toString: () => any; }) {
   const text = fn.toString();
   const match = text.match(/async(?:\s+function)?\s*\(\s*{\s*([^}]*)\s*}/);
   if (!match || !match[1].trim())
     return [];
   let signature = match[1];
-  return signature.split(',').map(t => t.trim());
+  return signature.split(',').map((t: string) => t.trim());
 }
 
-function optionParameterNames(fn) {
+function optionParameterNames(fn: { toString: () => any; }) {
   const text = fn.toString();
   const match = text.match(/(?:\s+function)?\s*\(\s*{\s*([^}]*)\s*}/);
   if (!match || !match[1].trim())
     return [];
   let signature = match[1];
-  return signature.split(',').map(t => t.trim());
+  return signature.split(',').map((t: string) => t.trim());
 }
 
-function innerRegisterFixture(name, scope, fn) {
-  const stackFrame = new Error().stack.split('\n').slice(1).filter(line => !line.includes(__filename))[0];
+function innerRegisterFixture(name: any, scope: string, fn: any, caller: Function) {
+  const obj = {stack: ''};
+  Error.captureStackTrace(obj, caller);
+  const stackFrame = obj.stack.split('\n')[1];
   const location = stackFrame.replace(/.*at Object.<anonymous> \((.*)\)/, '$1');
   const file = location.replace(/^(.+):\d+:\d+$/, '$1');
   const registration = { name, scope, fn, file, location };
@@ -183,32 +210,32 @@ function innerRegisterFixture(name, scope, fn) {
   registrationsByFile.get(file).push(registration);
 };
 
-function registerFixture(name, fn) {
-  innerRegisterFixture(name, 'test', fn);
+export function registerFixture<T extends keyof TestState>(name: T, fn: (params: FixtureParameters & WorkerState & TestState, test: (arg: TestState[T]) => Promise<void>) => Promise<void>) {
+  innerRegisterFixture(name, 'test', fn, registerFixture);
 };
 
-function registerWorkerFixture(name, fn) {
-  innerRegisterFixture(name, 'worker', fn);
+export function registerWorkerFixture<T extends keyof (WorkerState & FixtureParameters)>(name: T, fn: (params: FixtureParameters & WorkerState, test: (arg: (WorkerState & FixtureParameters)[T]) => Promise<void>) => Promise<void>) {
+  innerRegisterFixture(name, 'worker', fn, registerWorkerFixture);
 };
 
-function registerParameter(name, fn) {
-  registerWorkerFixture(name, async ({}, test) => await test(parameters[name]));
+export function registerParameter<T extends keyof WorkerState>(name: T, fn: () => WorkerState[T][]) {
+  registerWorkerFixture(name, async ({}: any, test: (arg0: any) => any) => await test(parameters[name]));
   parameterRegistrations.set(name, fn);
 }
 
-function collectRequires(file, result) {
+function collectRequires(file: string | number, result: Set<unknown>) {
   if (result.has(file))
     return;
   result.add(file);
   const cache = require.cache[file];
   if (!cache)
     return;
-  const deps = cache.children.map(m => m.id).slice().reverse();
+  const deps = cache.children.map((m: { id: any; }) => m.id).slice().reverse();
   for (const dep of deps)
     collectRequires(dep, result);
 }
 
-function lookupRegistrations(file, scope) {
+export function lookupRegistrations(file: any, scope: any) {
   const deps = new Set();
   collectRequires(file, deps);
   const allDeps = [...deps].reverse();
@@ -226,11 +253,9 @@ function lookupRegistrations(file, scope) {
   return result;
 }
 
-function rerunRegistrations(file, scope) {
+export function rerunRegistrations(file: any, scope: any) {
   // When we are running several tests in the same worker, we should re-run registrations before
   // each file. That way we erase potential fixture overrides from the previous test runs.
   for (const registration of lookupRegistrations(file, scope).values())
     registrations.set(registration.name, registration);
 }
-
-module.exports = { FixturePool, registerFixture, registerWorkerFixture, rerunRegistrations, lookupRegistrations, fixturesForCallback, registerParameter, setParameters, parameterRegistrations, parameters };
diff --git a/test/runner/fixturesUI.js b/test-runner/src/fixturesUI.js
similarity index 100%
rename from test/runner/fixturesUI.js
rename to test-runner/src/fixturesUI.js
diff --git a/test-runner/src/index.ts b/test-runner/src/index.ts
new file mode 100644
index 0000000000..00ad8b8db6
--- /dev/null
+++ b/test-runner/src/index.ts
@@ -0,0 +1,18 @@
+/**
+ * Copyright 2019 Google Inc. All rights reserved.
+ * Modifications copyright (c) Microsoft Corporation.
+ *
+ * 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.
+ */
+import './builtin.fixtures';
+export {registerFixture, registerWorkerFixture, registerParameter, parameters} from './fixtures';
\ No newline at end of file
diff --git a/test/runner/runner.js b/test-runner/src/runner.js
similarity index 98%
rename from test/runner/runner.js
rename to test-runner/src/runner.js
index 655d3cc866..c9cebc98ec 100644
--- a/test/runner/runner.js
+++ b/test-runner/src/runner.js
@@ -200,8 +200,8 @@ class OopWorker extends EventEmitter {
     this.process = child_process.fork(path.join(__dirname, 'worker.js'), {
       detached: false,
       env: {
-        FORCE_COLOR: process.stdout.isTTY ? 1 : 0,
-        DEBUG_COLORS: process.stdout.isTTY ? 1 : 0,
+        FORCE_COLOR: process.stdout.isTTY ? '1' : '0',
+        DEBUG_COLORS: process.stdout.isTTY ? '1' : '0',
         ...process.env
       },
       // Can't pipe since piping slows down termination for some reason.
diff --git a/test/runner/testCollector.js b/test-runner/src/testCollector.js
similarity index 99%
rename from test/runner/testCollector.js
rename to test-runner/src/testCollector.js
index 5a39c134e5..ee79ae4084 100644
--- a/test/runner/testCollector.js
+++ b/test-runner/src/testCollector.js
@@ -25,6 +25,7 @@ class TestCollector {
   constructor(files, matrix, options) {
     this._matrix = matrix;
     for (const name of Object.keys(matrix))
+      //@ts-ignore
       registerWorkerFixture(name, async ({}, test) => test());
     this._options = options;
     this.suite = new Mocha.Suite('', new Mocha.Context(), true);
diff --git a/test/runner/testRunner.js b/test-runner/src/testRunner.ts
similarity index 86%
rename from test/runner/testRunner.js
rename to test-runner/src/testRunner.ts
index 287dd2f41d..de4aea4e8c 100644
--- a/test/runner/testRunner.js
+++ b/test-runner/src/testRunner.ts
@@ -14,19 +14,42 @@
  * limitations under the License.
  */
 
-const path = require('path');
-const Mocha = require('mocha');
-const { FixturePool, registerWorkerFixture, rerunRegistrations, setParameters } = require('./fixtures');
-const { fixturesUI } = require('./fixturesUI');
-const { EventEmitter } = require('events');
+import path from 'path';
+import Mocha from 'mocha';
+import { FixturePool, registerWorkerFixture, rerunRegistrations, setParameters } from './fixtures';
+import { fixturesUI } from './fixturesUI';
+import { EventEmitter } from 'events';
 
-const fixturePool = new FixturePool();
+export const fixturePool = new FixturePool();
+declare global {
+  namespace NodeJS {
+    interface Global { 
+      expect: typeof import('expect')
+    }
+  }
+}
 global.expect = require('expect');
 const GoldenUtils = require('./GoldenUtils');
 
 class NullReporter {}
 
-class TestRunner extends EventEmitter {
+export class TestRunner extends EventEmitter {
+  mocha: any;
+  _currentOrdinal: number;
+  _failedWithError: boolean;
+  _file: any;
+  _ordinals: Set<unknown>;
+  _remaining: Set<unknown>;
+  _trialRun: any;
+  _passes: number;
+  _failures: number;
+  _pending: number;
+  _configuredFile: any;
+  _configurationObject: any;
+  _configurationString: any;
+  _parsedGeneratorConfiguration: {};
+  _relativeTestFile: string;
+  _runner: any;
   constructor(entry, options, workerId) {
     super();
     this.mocha = new Mocha({
@@ -53,6 +76,7 @@ class TestRunner extends EventEmitter {
     this._parsedGeneratorConfiguration = {};
     for (const {name, value} of this._configurationObject) {
       this._parsedGeneratorConfiguration[name] = value;
+      // @ts-ignore
       registerWorkerFixture(name, async ({}, test) => await test(value));
     }
     this._parsedGeneratorConfiguration['parallelIndex'] = workerId;
@@ -130,7 +154,7 @@ class TestRunner extends EventEmitter {
     await result;
   }
 
-  _shouldRunTest(hook) {
+  _shouldRunTest(hook = false) {
     if (this._trialRun || this._failedWithError)
       return false;
     if (hook) {
@@ -206,12 +230,10 @@ function serializeError(error) {
 
 let relativeTestFile;
 
-function initializeImageMatcher(options) {
+export function initializeImageMatcher(options) {
   function toMatchImage(received, name, config) {
     const { pass, message } = GoldenUtils.compare(received, name, { ...options, relativeTestFile, config });
     return { pass, message: () => message };
   };
   global.expect.extend({ toMatchImage });
 }
-
-module.exports = { TestRunner, initializeImageMatcher, fixturePool };
diff --git a/test/runner/transform.js b/test-runner/src/transform.js
similarity index 100%
rename from test/runner/transform.js
rename to test-runner/src/transform.js
diff --git a/test/runner/worker.js b/test-runner/src/worker.js
similarity index 98%
rename from test/runner/worker.js
rename to test-runner/src/worker.js
index 8c971fc63c..1b0dd745ba 100644
--- a/test/runner/worker.js
+++ b/test-runner/src/worker.js
@@ -32,10 +32,12 @@ function chunkToParams(chunk) {
 
 process.stdout.write = chunk => {
   sendMessageToParent('stdout', chunkToParams(chunk));
+  return true;
 };
 
 process.stderr.write = chunk => {
   sendMessageToParent('stderr', chunkToParams(chunk));
+  return true;
 };
 
 process.on('disconnect', gracefullyCloseAndExit);
diff --git a/test-runner/tsconfig.json b/test-runner/tsconfig.json
new file mode 100644
index 0000000000..bdffe99530
--- /dev/null
+++ b/test-runner/tsconfig.json
@@ -0,0 +1,20 @@
+{
+  "compilerOptions": {
+    "moduleResolution": "node",
+    "target": "ESNext",
+    "module": "commonjs",
+    "lib": ["esnext", "dom", "DOM.Iterable"],
+    "sourceMap": true,
+    "rootDir": "./src",
+    "outDir": "./lib",
+    "esModuleInterop": true,
+    "allowSyntheticDefaultImports": true,
+    "declaration": true,
+    "allowJs": true,
+    "checkJs": true,
+    "declarationMap": true
+  },
+  "compileOnSave": true,
+  "include": ["src"],
+  "exclude": ["node_modules"]
+}
\ No newline at end of file
diff --git a/test/chromium/oopif.spec.ts b/test/chromium/oopif.spec.ts
index 27bd3b48ab..b48be9e835 100644
--- a/test/chromium/oopif.spec.ts
+++ b/test/chromium/oopif.spec.ts
@@ -15,7 +15,7 @@
  */
 
 import { options } from '../playwright.fixtures';
-import { registerWorkerFixture } from '../runner';
+import { registerWorkerFixture } from '../../test-runner';
 
 registerWorkerFixture('browser', async ({browserType, defaultBrowserOptions}, test) => {
   const browser = await browserType.launch({
diff --git a/test/chromium/tracing.spec.ts b/test/chromium/tracing.spec.ts
index cdb045b4bf..2d7d63c83c 100644
--- a/test/chromium/tracing.spec.ts
+++ b/test/chromium/tracing.spec.ts
@@ -15,7 +15,7 @@
  */
 
 import { options } from '../playwright.fixtures';
-import { registerFixture } from '../runner';
+import { registerFixture } from '../../test-runner';
 
 import fs from 'fs';
 import path from 'path';
diff --git a/test/defaultbrowsercontext.spec.ts b/test/defaultbrowsercontext.spec.ts
index 88e520c26e..d808ad24df 100644
--- a/test/defaultbrowsercontext.spec.ts
+++ b/test/defaultbrowsercontext.spec.ts
@@ -16,7 +16,7 @@
  */
 
 import { options } from './playwright.fixtures';
-import { registerFixture } from './runner';
+import { registerFixture } from '../test-runner';
 import fs from 'fs';
 import utils from './utils';
 import { BrowserType, Browser, BrowserContext, Page } from '..';
diff --git a/test/downloads-path.spec.ts b/test/downloads-path.spec.ts
index 4eee958828..3ca44b1161 100644
--- a/test/downloads-path.spec.ts
+++ b/test/downloads-path.spec.ts
@@ -17,7 +17,7 @@
 
 import './playwright.fixtures';
 
-import { registerFixture } from './runner';
+import { registerFixture } from '../test-runner';
 
 import path from 'path';
 import fs from 'fs';
diff --git a/test/electron/electron.fixture.ts b/test/electron/electron.fixture.ts
index 1d5be653f8..3d35a2e7f7 100644
--- a/test/electron/electron.fixture.ts
+++ b/test/electron/electron.fixture.ts
@@ -15,7 +15,7 @@
  */
 
 import { options } from '../playwright.fixtures';
-import { registerFixture } from '../runner';
+import { registerFixture } from '../../test-runner';
 import {ElectronApplication, ElectronLauncher, ElectronPage} from '../../electron-types';
 import path from 'path';
 
diff --git a/test/fixtures.spec.ts b/test/fixtures.spec.ts
index b2a59a4a4e..6b0c9d520b 100644
--- a/test/fixtures.spec.ts
+++ b/test/fixtures.spec.ts
@@ -15,7 +15,7 @@
  * limitations under the License.
  */
 import { options } from './playwright.fixtures';
-import { registerFixture } from './runner';
+import { registerFixture } from '../test-runner';
 
 import path from 'path';
 import {spawn, execSync} from 'child_process';
diff --git a/test/playwright.fixtures.ts b/test/playwright.fixtures.ts
index 6ba20c5d85..7678425e50 100644
--- a/test/playwright.fixtures.ts
+++ b/test/playwright.fixtures.ts
@@ -24,7 +24,7 @@ import { Connection } from '../lib/rpc/client/connection';
 import { Transport } from '../lib/rpc/transport';
 import { setUnderTest } from '../lib/helper';
 import { installCoverageHooks } from './coverage';
-import { parameters, registerFixture, registerWorkerFixture } from './runner';
+import { parameters, registerFixture, registerWorkerFixture } from '../test-runner';
 
 import {mkdtempAsync, removeFolderAsync} from './utils';
 
@@ -40,6 +40,7 @@ declare global {
     playwright: typeof import('../index');
     browserType: BrowserType<Browser>;
     browser: Browser;
+    httpService: {server: TestServer, httpsServer: TestServer}
   }
   interface TestState {
     toImpl: (rpcObject: any) => any;
@@ -53,7 +54,7 @@ declare global {
     browserName: string;
     headless: boolean;
     wire: boolean;
-    slowMo: boolean;
+    slowMo: number;
   }
 }
 
diff --git a/test/proxy.spec.ts b/test/proxy.spec.ts
index c95ecc90e2..fb31f5e5e8 100644
--- a/test/proxy.spec.ts
+++ b/test/proxy.spec.ts
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-import { parameters } from './runner';
+import { parameters } from '../test-runner';
 import { options } from './playwright.fixtures';
 
 import socks from 'socksv5';
diff --git a/test/runner/index.ts b/test/runner/index.ts
deleted file mode 100644
index 33fc93a84c..0000000000
--- a/test/runner/index.ts
+++ /dev/null
@@ -1,46 +0,0 @@
-/**
- * Copyright Microsoft Corporation. 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.
- */
-
-const os = require('os');
-const path = require('path');
-const { mkdtempAsync, removeFolderAsync } = require('../utils');
-
-const {
-  parameters: jsParameters,
-  registerFixture: jsRegisterFixture,
-  registerWorkerFixture: jsRegisterWorkerFixture,
-  registerParameter: jsRegisterParameter
-} = require('./fixtures');
-
-declare global {
-  interface FixtureParameters {
-    parallelIndex: number;
-  }
-  interface WorkerState {
-    tmpDir: string;
-  }
-}
-
-export const parameters: FixtureParameters = jsParameters;
-export const registerFixture = jsRegisterFixture;
-export const registerWorkerFixture = jsRegisterWorkerFixture
-export const registerParameter = jsRegisterParameter;
-
-registerFixture('tmpDir', async ({}, test) => {
-  const tmpDir = await mkdtempAsync(path.join(os.tmpdir(), 'playwright-test-'));
-  await test(tmpDir);
-  await removeFolderAsync(tmpDir).catch(e => {});
-});
diff --git a/test/screencast.spec.ts b/test/screencast.spec.ts
index 359b5c83cd..f2bb80e646 100644
--- a/test/screencast.spec.ts
+++ b/test/screencast.spec.ts
@@ -15,7 +15,7 @@
  */
 
 import { options } from './playwright.fixtures';
-import { registerFixture } from './runner';
+import { registerFixture } from '../test-runner';
 import { Page } from '..';
 
 import fs from 'fs';
diff --git a/test/test-runner-helper.ts b/test/test-runner-helper.ts
index 858a7dadef..1f8d8de441 100644
--- a/test/test-runner-helper.ts
+++ b/test/test-runner-helper.ts
@@ -15,7 +15,7 @@
  * limitations under the License.
  */
 
-import { registerFixture } from './runner';
+import { registerFixture } from '../test-runner';
 
 declare global {
   interface TestState {
diff --git a/test/test-runner-overrides-1.spec.ts b/test/test-runner-overrides-1.spec.ts
index 9373ca6f5d..1e9fafddd2 100644
--- a/test/test-runner-overrides-1.spec.ts
+++ b/test/test-runner-overrides-1.spec.ts
@@ -15,7 +15,7 @@
  */
 
 import './test-runner-helper';
-import { registerFixture } from './runner';
+import { registerFixture } from '../test-runner';
 
 registerFixture('helperFixture', async ({}, test) => {
   await test('helperFixture - overridden');
diff --git a/test/types.d.ts b/test/types.d.ts
index 6799501bc6..6c6ecfccf2 100644
--- a/test/types.d.ts
+++ b/test/types.d.ts
@@ -17,29 +17,6 @@
 type ServerResponse = import('http').ServerResponse;
 type IncomingMessage = import('http').IncomingMessage;
 
-type DescribeFunction = ((name: string, inner: () => void) => void) & {
-    fail(condition: boolean): DescribeFunction;
-    skip(condition: boolean): DescribeFunction;
-    slow(): DescribeFunction;
-    repeat(n: number): DescribeFunction;
-};
-
-type ItFunction<STATE> = ((name: string, inner: (state: STATE) => Promise<void>) => void) & {
-    fail(condition: boolean): ItFunction<STATE>;
-    skip(condition: boolean): ItFunction<STATE>;
-    slow(): ItFunction<STATE>;
-    repeat(n: number): ItFunction<STATE>;
-};
-
-interface FixtureParameters {
-}
-
-interface WorkerState {
-}
-
-interface TestState {
-}
-
 declare module '' {
     module 'expect/build/types' {
         interface Matchers<R> {
@@ -49,20 +26,6 @@ declare module '' {
 }
 
 declare const expect: typeof import('expect');
-
-declare const describe: DescribeFunction;
-declare const fdescribe: DescribeFunction;
-declare const xdescribe: DescribeFunction;
-declare const it: ItFunction<TestState & WorkerState & FixtureParameters>;
-declare const fit: ItFunction<TestState & WorkerState & FixtureParameters>;
-declare const dit: ItFunction<TestState & WorkerState & FixtureParameters>;
-declare const xit: ItFunction<TestState & WorkerState & FixtureParameters>;
-
-declare const beforeEach: (inner: (state: TestState & WorkerState & FixtureParameters) => Promise<void>) => void;
-declare const afterEach: (inner: (state: TestState & WorkerState & FixtureParameters) => Promise<void>) => void;
-declare const beforeAll: (inner: (state: WorkerState) => Promise<void>) => void;
-declare const afterAll: (inner: (state: WorkerState) => Promise<void>) => void;
-
 declare const browserType: import('../index').BrowserType<import('../index').Browser>;
 
 declare var MAC: boolean;
diff --git a/utils/doclint/check_public_api/test/test.js b/utils/doclint/check_public_api/test/test.js
index 4614c35a08..0211afe993 100644
--- a/utils/doclint/check_public_api/test/test.js
+++ b/utils/doclint/check_public_api/test/test.js
@@ -20,7 +20,7 @@ const checkPublicAPI = require('..');
 const Source = require('../../Source');
 const mdBuilder = require('../MDBuilder');
 const jsBuilder = require('../JSBuilder');
-const { registerWorkerFixture } = require('../../../../test/runner');
+const { registerWorkerFixture } = require('../../../../test-runner');
 
 registerWorkerFixture('page', async({}, test) => {
   const browser = await playwright.chromium.launch();
diff --git a/utils/watch.js b/utils/watch.js
index 756dd915eb..b94228eb51 100644
--- a/utils/watch.js
+++ b/utils/watch.js
@@ -21,6 +21,7 @@ const fs = require('fs');
 const spawns = [
   child_process.spawn('node', [path.join(__dirname, 'runWebpack.js'), '--mode="development"', '--watch', '--silent'], { stdio: 'inherit', shell: true }),
   child_process.spawn('npx', ['tsc', '-w', '--preserveWatchOutput', '-p', path.join(__dirname, '..')], { stdio: 'inherit', shell: true }),
+  child_process.spawn('npx', ['tsc', '-w', '--preserveWatchOutput', '-p', path.join(__dirname, '..', 'test-runner')], { stdio: 'inherit', shell: true }),
 ];
 process.on('exit', () => spawns.forEach(s => s.kill()));