Finalise A/B test migration and drop @guardian/ab-core

dotcom-rendering/.storybook/preview.ts

@@ -1,4 +1,3 @@
-import { AB } from '@guardian/ab-core';
 import { setCookie, storage } from '@guardian/libs';
 import { resets } from '@guardian/source/foundations';
 import { palette as sourcePalette } from '@guardian/source/foundations';
@@ -12,6 +11,7 @@ import { Lazy } from '../src/components/Lazy';
 import { Picture } from '../src/components/Picture';
 import { rawFontsCss } from '../src/lib/fonts-css';
 import { mockFetch } from '../src/lib/mockRESTCalls';
+import { ABTests } from '../src/experiments/lib/ab-tests';
 import { setABTests } from '../src/lib/useAB';
 import { ConfigContextDecorator } from './decorators/configContextDecorator';
 import {
@@ -42,19 +42,7 @@ global.fetch = mockFetch;
 // Fix the date to prevent false negatives
 MockDate.set('Sat Jan 1 2022 12:00:00 GMT+0000 (Greenwich Mean Time)');
 
-setABTests({
-	api: new AB({
-		mvtMaxValue: 1_000_000,
-		mvtId: 1234,
-		pageIsSensitive: false,
-		abTestSwitches: {},
-		arrayOfTestObjects: [],
-		serverSideTests: {},
-		ophanRecord: () => {},
-		errorReporter: () => {},
-	}),
-	participations: {},
-});
+setABTests(new ABTests({ isServer: true, serverSideABTests: {} }));
 
 // Add base css for the site
 const css = `${rawFontsCss}${resets.resetCSS}`;

dotcom-rendering/README.md

@@ -173,7 +173,7 @@ We recommend you update your workspace settings to automatically fix formatting
 | <img alt="Chromatic" src="./docs/images/logo-chromatic.jpg" width="350" />                                                 | [Chromatic](https://www.chromatic.com/) is a visual regression testing tool that tests our Storybook components at PR time.                                                                                                                                                                                                                       |
 | <img alt="Jest" src="./docs/images/logo-jest.jpg" width="350" />                                                           | [Jest](https://jestjs.io) is a unit testing tool. You will find Jest tests in the repo with `.test.` filenames.                                                                                                                                                                                                                                   |
 | <img alt="Playwright" src="./docs/images/logo-playwright.svg" width="350" />                                               | [Playwright](https://playwright.dev/) is an integration testing tool that runs tests in the browser. You will find the Playwright tests in the [playwright directory](./playwright).                                                                                                                                                              |
-| <img alt="AB Testing" src="./docs/images/logo-ab-testing.png" width="350" />                                               | The [A/B Testing library](https://github.com/guardian/csnx/tree/main/libs/@guardian/ab-core) is an internal NPM Module. There are [docs here](./docs/development/ab-testing-in-dcr.md).                                                                                                                                                           |
+| <img alt="AB Testing" src="./docs/images/logo-ab-testing.png" width="350" />                                               | The A/B Testing framework is developed in-house. There are [docs here](./docs/development/ab-testing-in-dcr.md).                                                                                                                                                                                                                                  |
 | <img alt="Deno" title="Deno logo, MIT License: https://deno.land/artwork" src="./docs/images/logo-deno.svg" width="350" /> | [Deno](https://deno.land/) is a JavaScript runtime that we've started incorporating into some of our Github Actions workflows. You will only need to install it if you are planning to run the workflow scripts locally. Some installation and troubleshooting instructions can be found in the [Deno scripts folder](../scripts/deno/README.md). |
 
 ## Concepts

dotcom-rendering/docs/development/ab-testing-in-dcr.md

@@ -2,8 +2,6 @@
 
 This documentation covers the updated A/B test framework, developed by commercial-dev to support both client and server side A/B tests in DCR and launched in January 2026. If you're interested in how it works please visit the docs [here](https://github.com/guardian/dotcom-rendering/tree/main/ab-testing).
 
-Instructions for the legacy framework can still be found [here](./legacy-ab-testing-in-dcr.md).
-
 ## Creating a new A/B test
 
 ### 1. Configure your A/B test

dotcom-rendering/package.json

@@ -27,7 +27,6 @@
 		"@emotion/cache": "11.14.0",
 		"@emotion/react": "11.14.0",
 		"@emotion/server": "11.11.0",
-		"@guardian/ab-core": "8.0.0",
 		"@guardian/ab-testing-config": "workspace:ab-testing-config",
 		"@guardian/braze-components": "22.2.0",
 		"@guardian/bridget": "8.11.0",

dotcom-rendering/src/components/AdmiralScript.island.tsx

@@ -4,7 +4,7 @@ import { cmp } from '@guardian/consent-manager';
 import { getCookie, log } from '@guardian/libs';
 import { useEffect } from 'react';
 import { getOphan } from '../client/ophan/ophan';
-import { useBetaAB } from '../lib/useAB';
+import { useAB } from '../lib/useAB';
 import { useConfig } from './ConfigContext';
 
 const testName = 'growth-admiral-adblock-detect';
@@ -210,7 +210,7 @@ const setUpAdmiralEventLogger = (
 
 export const AdmiralScript = () => {
 	const { renderingTarget } = useConfig();
-	const abTests = useBetaAB();
+	const abTests = useAB();
 	const isInVariantDetectGroup =
 		abTests?.isUserInTestGroup(testName, 'variant-detect') ?? false;
 	const variantName = isInVariantDetectGroup

dotcom-rendering/src/components/ArticlePage.tsx

@@ -4,7 +4,6 @@ import { DecideLayout } from '../layouts/DecideLayout';
 import { buildAdTargeting } from '../lib/ad-targeting';
 import { ArticleDesign } from '../lib/articleFormat';
 import { rootStyles } from '../lib/rootStyles';
-import { filterABTestSwitches } from '../model/enhance-switches';
 import type { NavType } from '../model/extract-nav';
 import type { Article } from '../types/article';
 import type { RenderingTarget } from '../types/renderingTarget';
@@ -132,12 +131,6 @@ export const ArticlePage = (props: WebProps | AppProps) => {
 					</Island>
 					<Island priority="critical">
 						<SetABTests
-							abTestSwitches={filterABTestSwitches(
-								frontendData.config.switches,
-							)}
-							pageIsSensitive={frontendData.config.isSensitive}
-							isDev={!!frontendData.config.isDev}
-							serverSideTests={frontendData.config.abTests}
 							serverSideABTests={
 								frontendData.config.serverSideABTests
 							}

dotcom-rendering/src/components/DirectoryPageNav.island.tsx

@@ -13,7 +13,7 @@ import {
 import { grid } from '../grid';
 import { getInteractionClient } from '../lib/bridgetApi';
 import { generateImageURL } from '../lib/image';
-import { useBetaAB } from '../lib/useAB';
+import { useAB } from '../lib/useAB';
 import { worldCup2026PageIds } from '../lib/worldCup2026';
 import {
 	WorldCup2026Icon,
@@ -254,7 +254,7 @@ export const DirectoryPageNav = ({ pageId, pageTags }: Props) => {
 
 	const isApps = renderingTarget === 'Apps';
 
-	const ab = useBetaAB();
+	const ab = useAB();
 
 	const config = configs.find(
 		(cfg) =>

dotcom-rendering/src/components/DirectoryPageNav.stories.tsx

@@ -1,17 +1,17 @@
 import { allModes } from '../../.storybook/modes';
 import preview from '../../.storybook/preview';
-import { BetaABTests } from '../experiments/lib/beta-ab-tests';
-import { setBetaABTests } from '../lib/useAB';
+import { ABTests } from '../experiments/lib/ab-tests';
+import { setABTests } from '../lib/useAB';
 import { ConfigProvider } from './ConfigContext';
 import { DirectoryPageNav } from './DirectoryPageNav.island';
 
-const mockAB = new BetaABTests({
+const mockAB = new ABTests({
 	isServer: true,
 	serverSideABTests: {
 		'webx-world-cup-2026-subnav': 'enable',
 	},
 });
-setBetaABTests(mockAB);
+setABTests(mockAB);
 
 const meta = preview.meta({
 	component: DirectoryPageNav,

dotcom-rendering/src/components/EmailSignUpWrapper.island.test.tsx

@@ -5,7 +5,7 @@ import {
 	AB_TEST_NAME,
 	NEWSLETTER_SIGNUP_COMPONENT_ID,
 } from '../lib/newsletterSignupTracking';
-import { useBetaAB } from '../lib/useAB';
+import { useAB } from '../lib/useAB';
 import { useIsSignedIn } from '../lib/useAuthStatus';
 import { useNewsletterSubscription } from '../lib/useNewsletterSubscription';
 import { ConfigProvider } from './ConfigContext';
@@ -16,7 +16,7 @@ jest.mock('../client/ophan/ophan', () => ({
 }));
 
 jest.mock('../lib/useAB', () => ({
-	useBetaAB: jest.fn(),
+	useAB: jest.fn(),
 }));
 
 jest.mock('../lib/useAuthStatus', () => ({
@@ -87,7 +87,7 @@ const renderWrapper = (props = {}, renderingTarget: 'Web' | 'Apps' = 'Web') =>
 	);
 
 const mockAbTests = (isInVariant: boolean) => {
-	(useBetaAB as jest.Mock).mockReturnValue({
+	(useAB as jest.Mock).mockReturnValue({
 		isUserInTestGroup: (_testName: string, group: string) =>
 			group === 'variant' ? isInVariant : !isInVariant,
 	});
@@ -97,7 +97,7 @@ describe('EmailSignUpWrapper', () => {
 	beforeEach(() => {
 		jest.resetAllMocks();
 		// Default: AB API not yet hydrated
-		(useBetaAB as jest.Mock).mockReturnValue(undefined);
+		(useAB as jest.Mock).mockReturnValue(undefined);
 		(useIsSignedIn as jest.Mock).mockReturnValue(false);
 		(useNewsletterSubscription as jest.Mock).mockReturnValue(false);
 	});
@@ -137,7 +137,7 @@ describe('EmailSignUpWrapper', () => {
 
 	describe('flag on (showNewNewsletterSignupCard = true)', () => {
 		it('shows a placeholder when AB API has not hydrated yet', () => {
-			// useBetaAB returns undefined before hydration — component shows
+			// useAB returns undefined before hydration — component shows
 			// Placeholder rather than committing to control or variant early.
 			// (default set in outer beforeEach, no override needed)
 			renderWrapper({ showNewNewsletterSignupCard: true });
@@ -187,7 +187,7 @@ describe('EmailSignUpWrapper', () => {
 
 	describe('Apps rendering target', () => {
 		it('renders the legacy EmailSignup without waiting for AB to resolve', () => {
-			// useBetaAB remains undefined (AB framework never initialises on Apps)
+			// useAB remains undefined (AB framework never initialises on Apps)
 			// but the component should not block on it
 			renderWrapper({ showNewNewsletterSignupCard: true }, 'Apps');
 			expect(screen.getByTestId('email-signup')).toBeInTheDocument();
@@ -280,7 +280,7 @@ describe('EmailSignUpWrapper', () => {
 		});
 
 		it('does not fire a VIEW event while the AB client has not hydrated', () => {
-			// useBetaAB returns undefined — default set in beforeEach
+			// useAB returns undefined — default set in beforeEach
 			renderWrapper({ showNewNewsletterSignupCard: true });
 
 			expect(submitComponentEvent).not.toHaveBeenCalled();

dotcom-rendering/src/components/EmailSignUpWrapper.island.tsx

@@ -5,7 +5,7 @@ import {
 	NEWSLETTER_SIGNUP_COMPONENT_ID,
 	sendNewsletterSignupEvent,
 } from '../lib/newsletterSignupTracking';
-import { useBetaAB } from '../lib/useAB';
+import { useAB } from '../lib/useAB';
 import { useIsSignedIn } from '../lib/useAuthStatus';
 import { useNewsletterSubscription } from '../lib/useNewsletterSubscription';
 import { useConfig } from './ConfigContext';
@@ -78,7 +78,7 @@ export const EmailSignUpWrapper = ({
 	const abTestEnabled =
 		showNewNewsletterSignupCard && renderingTarget === 'Web';
 
-	const abTests = useBetaAB();
+	const abTests = useAB();
 	const abResolved = abTests !== undefined;
 
 	const isVariant =

dotcom-rendering/src/components/EmailSignUpWrapper.stories.tsx

@@ -2,14 +2,14 @@ import type { StoryObj } from '@storybook/react-webpack5';
 import { mocked, within } from 'storybook/test';
 import preview from '../../.storybook/preview';
 import { lazyFetchEmailWithTimeout } from '../lib/fetchEmail';
-import { useBetaAB } from '../lib/useAB';
+import { useAB } from '../lib/useAB';
 import { useIsSignedIn } from '../lib/useAuthStatus';
 import { useNewsletterSubscription } from '../lib/useNewsletterSubscription';
 import { EmailSignUpWrapper } from './EmailSignUpWrapper.island';
 
-/** Resolves `useBetaAB` as if the AB framework has hydrated, placing the user in control or variant. */
+/** Resolves `useAB` as if the AB framework has hydrated, placing the user in control or variant. */
 const mockBetaAB = (isInVariant: boolean) => {
-	mocked(useBetaAB).mockReturnValue({
+	mocked(useAB).mockReturnValue({
 		isUserInTestGroup: (_testName: string, group: string) =>
 			group === 'variant' ? isInVariant : !isInVariant,
 		isUserInTest: () => true,

dotcom-rendering/src/components/EnhanceAffiliateLinks.island.tsx

@@ -1,7 +1,7 @@
 import { useEffect } from 'react';
 import { buildXcustParamForAffiliateLink } from '../lib/affiliateLinksUtils';
 import { safeParseURL } from '../lib/parse';
-import { useBetaAB } from '../lib/useAB';
+import { useAB } from '../lib/useAB';
 
 /**
  * Add custom parameters to skimlink URLs:
@@ -44,7 +44,7 @@ const utmKeys = [
 ];
 
 export const EnhanceAffiliateLinks = () => {
-	const abTests = useBetaAB();
+	const abTests = useAB();
 
 	// Get users server & client-side AB test participations
 	const abTestParticipations = abTests?.getParticipations();

dotcom-rendering/src/components/EnhanceAffiliateLinks.test.tsx

@@ -1,11 +1,11 @@
 import '@testing-library/jest-dom';
 import { render } from '@testing-library/react';
-import { useBetaAB } from '../lib/useAB';
+import { useAB } from '../lib/useAB';
 import { EnhanceAffiliateLinks } from './EnhanceAffiliateLinks.island';
 
 // Mock the useAB module
 jest.mock('../lib/useAB', () => ({
-	useBetaAB: jest.fn(),
+	useAB: jest.fn(),
 }));
 
 describe('EnhanceAffiliateLinks', () => {
@@ -67,7 +67,7 @@ describe('EnhanceAffiliateLinks', () => {
             <a href="https://go.skimresources.com/?id=12345">Skimlink</a>
         `;
 
-		(useBetaAB as jest.Mock).mockReturnValue({
+		(useAB as jest.Mock).mockReturnValue({
 			getParticipations: () => ({
 				test1: 'variantA',
 				test2: 'variantB',

dotcom-rendering/src/components/FrontPage.tsx

@@ -4,7 +4,6 @@ import { FrontLayout } from '../layouts/FrontLayout';
 import { buildAdTargeting } from '../lib/ad-targeting';
 import { ArticleDesign, ArticleDisplay, Pillar } from '../lib/articleFormat';
 import { rootStyles } from '../lib/rootStyles';
-import { filterABTestSwitches } from '../model/enhance-switches';
 import type { NavType } from '../model/extract-nav';
 import type { Front } from '../types/front';
 import { AdmiralScript } from './AdmiralScript.island';
@@ -81,10 +80,6 @@ export const FrontPage = ({ front, NAV }: Props) => {
 			</Island>
 			<Island priority="critical">
 				<SetABTests
-					abTestSwitches={filterABTestSwitches(front.config.switches)}
-					pageIsSensitive={front.config.isSensitive}
-					isDev={!!front.config.isDev}
-					serverSideTests={front.config.abTests}
 					serverSideABTests={front.config.serverSideABTests}
 				/>
 			</Island>

dotcom-rendering/src/components/HostedContentPage.tsx

@@ -5,7 +5,6 @@ import { HostedGalleryLayout } from '../layouts/HostedGalleryLayout';
 import { HostedVideoLayout } from '../layouts/HostedVideoLayout';
 import { ArticleDesign } from '../lib/articleFormat';
 import { rootStyles } from '../lib/rootStyles';
-import { filterABTestSwitches } from '../model/enhance-switches';
 import type { Article } from '../types/article';
 import type { RenderingTarget } from '../types/renderingTarget';
 import { AlreadyVisited } from './AlreadyVisited.island';
@@ -116,12 +115,6 @@ export const HostedContentPage = (props: WebProps | AppProps) => {
 
 					<Island priority="critical">
 						<SetABTests
-							abTestSwitches={filterABTestSwitches(
-								frontendData.config.switches,
-							)}
-							pageIsSensitive={frontendData.config.isSensitive}
-							isDev={!!frontendData.config.isDev}
-							serverSideTests={frontendData.config.abTests}
 							serverSideABTests={
 								frontendData.config.serverSideABTests
 							}