diff --git a/test/browsercontext-user-agent.spec.ts b/test/browsercontext-user-agent.spec.ts
index 1b293fcb37..22dd11b63f 100644
--- a/test/browsercontext-user-agent.spec.ts
+++ b/test/browsercontext-user-agent.spec.ts
@@ -17,7 +17,6 @@
 import './playwright.fixtures';
 
 import utils from './utils';
-const {devices} = require('..');
 
 it('should work', async({browser, server}) => {
   {
@@ -57,7 +56,7 @@ it('should work for subframes', async({browser, server}) => {
   }
 });
 
-it('should emulate device user-agent', async({browser, server}) => {
+it('should emulate device user-agent', async({browser, server, playwright}) => {
   {
     const context = await browser.newContext();
     const page = await context.newPage();
@@ -66,7 +65,7 @@ it('should emulate device user-agent', async({browser, server}) => {
     await context.close();
   }
   {
-    const context = await browser.newContext({ userAgent: devices['iPhone 6'].userAgent });
+    const context = await browser.newContext({ userAgent: playwright.devices['iPhone 6'].userAgent });
     const page = await context.newPage();
     await page.goto(server.PREFIX + '/mobile.html');
     expect(await page.evaluate(() => navigator.userAgent)).toContain('iPhone');
diff --git a/test/channels.spec.ts b/test/channels.spec.ts
index c4774ff9c5..4cbc5d202f 100644
--- a/test/channels.spec.ts
+++ b/test/channels.spec.ts
@@ -15,7 +15,7 @@
  * limitations under the License.
  */
 import { options } from './playwright.fixtures';
-import { ChromiumBrowser } from '..';
+import type { ChromiumBrowser } from '..';
 
 it('should work', async({browser}) => {
   expect(!!browser['_connection']).toBeTruthy();
diff --git a/test/chromium/chromium.spec.ts b/test/chromium/chromium.spec.ts
index 796feb6659..09c37f8178 100644
--- a/test/chromium/chromium.spec.ts
+++ b/test/chromium/chromium.spec.ts
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 import { options } from '../playwright.fixtures';
-import { ChromiumBrowserContext } from '../..';
+import type { ChromiumBrowserContext } from '../..';
 
 it.skip(!options.CHROMIUM)('should create a worker from a service worker', async({page, server, context}) => {
   const [worker] = await Promise.all([
diff --git a/test/chromium/launcher.spec.ts b/test/chromium/launcher.spec.ts
index 90216e9992..aa68c8ca79 100644
--- a/test/chromium/launcher.spec.ts
+++ b/test/chromium/launcher.spec.ts
@@ -17,7 +17,7 @@ import { options } from '../playwright.fixtures';
 
 import path from 'path';
 import utils from '../utils';
-import { ChromiumBrowser, ChromiumBrowserContext } from '../..';
+import type { ChromiumBrowser, ChromiumBrowserContext } from '../..';
 const { makeUserDataDir, removeUserDataDir } = utils;
 
 it.skip(options.WIRE || !options.CHROMIUM)('should throw with remote-debugging-pipe argument', async({browserType, defaultBrowserOptions}) => {
diff --git a/test/chromium/tracing.spec.ts b/test/chromium/tracing.spec.ts
index 2d7d63c83c..ec60a5a2a8 100644
--- a/test/chromium/tracing.spec.ts
+++ b/test/chromium/tracing.spec.ts
@@ -19,7 +19,7 @@ import { registerFixture } from '../../test-runner';
 
 import fs from 'fs';
 import path from 'path';
-import { ChromiumBrowser } from '../..';
+import type { ChromiumBrowser } from '../..';
 
 declare global {
   interface TestState {
diff --git a/test/downloads-path.spec.ts b/test/downloads-path.spec.ts
index 3ca44b1161..059354ff46 100644
--- a/test/downloads-path.spec.ts
+++ b/test/downloads-path.spec.ts
@@ -23,7 +23,7 @@ import path from 'path';
 import fs from 'fs';
 import os from 'os';
 import {mkdtempAsync, removeFolderAsync} from './utils';
-import { Browser, BrowserContext } from '..';
+import type { Browser, BrowserContext } from '..';
 
 declare global {
   interface TestState {
diff --git a/test/page-network-idle.spec.ts b/test/page-network-idle.spec.ts
index 7deb985ed4..14d71922a0 100644
--- a/test/page-network-idle.spec.ts
+++ b/test/page-network-idle.spec.ts
@@ -16,7 +16,7 @@
  */
 
 import './playwright.fixtures';
-import { Frame, Page } from '..';
+import type { Frame, Page } from '..';
 import { TestServer } from '../utils/testserver';
 
 it('should navigate to empty page with networkidle', async({page, server}) => {
diff --git a/test/page-wait-for-load-state.spec.ts b/test/page-wait-for-load-state.spec.ts
index fa5827795c..a475a52a80 100644
--- a/test/page-wait-for-load-state.spec.ts
+++ b/test/page-wait-for-load-state.spec.ts
@@ -16,7 +16,7 @@
  */
 
 import { options } from './playwright.fixtures';
-import { Route } from '..';
+import type { Route } from '..';
 
 it('should pick up ongoing navigation', async({page, server}) => {
   let response = null;
diff --git a/test/page-wait-for-navigation.spec.ts b/test/page-wait-for-navigation.spec.ts
index c94b6d9b06..ac48f4860e 100644
--- a/test/page-wait-for-navigation.spec.ts
+++ b/test/page-wait-for-navigation.spec.ts
@@ -18,7 +18,7 @@
 import { options } from './playwright.fixtures';
 
 import utils from './utils';
-import { Frame } from '..';
+import type { Frame } from '..';
 
 it('should work', async({page, server}) => {
   await page.goto(server.EMPTY_PAGE);
diff --git a/test/playwright.fixtures.ts b/test/playwright.fixtures.ts
index 178da4cb3c..33e108a9ab 100644
--- a/test/playwright.fixtures.ts
+++ b/test/playwright.fixtures.ts
@@ -113,6 +113,9 @@ registerWorkerFixture('defaultBrowserOptions', async({browserName}, test) => {
 });
 
 registerWorkerFixture('playwright', async({browserName}, test) => {
+  const playwrightCacheEntry = require.cache[require.resolve('../index')];
+  if (playwrightCacheEntry)
+    throw new Error('Could not set playwright to test mode because it was required directly from ' + playwrightCacheEntry.parent.id);
   setUnderTest(); // Note: we must call setUnderTest before requiring Playwright
 
   const {coverage, uninstall} = installCoverageHooks(browserName);
diff --git a/test/remoteServer.fixture.ts b/test/remoteServer.fixture.ts
index bc70a82e92..bdb3f685db 100644
--- a/test/remoteServer.fixture.ts
+++ b/test/remoteServer.fixture.ts
@@ -18,7 +18,7 @@ import { registerFixture } from '../test-runner/lib';
 
 import path from 'path';
 import { spawn } from 'child_process';
-import { BrowserType, Browser, LaunchOptions } from '..';
+import type { BrowserType, Browser, LaunchOptions } from '..';
 
 declare global {
   interface TestState {
diff --git a/test/screencast.spec.ts b/test/screencast.spec.ts
index 80fd5c4908..570b9e392d 100644
--- a/test/screencast.spec.ts
+++ b/test/screencast.spec.ts
@@ -16,7 +16,7 @@
 
 import { options } from './playwright.fixtures';
 import { registerFixture } from '../test-runner';
-import { Page } from '..';
+import type { Page } from '..';
 
 import fs from 'fs';
 import path from 'path';
diff --git a/test/workers.spec.ts b/test/workers.spec.ts
index fd89dd282b..8268746936 100644
--- a/test/workers.spec.ts
+++ b/test/workers.spec.ts
@@ -16,7 +16,7 @@
  */
 
 import './playwright.fixtures';
-import { ConsoleMessage } from '..';
+import type { ConsoleMessage } from '..';
 
 it('Page.workers', async function({page, server}) {
   await Promise.all([