[NASAA-203/204] - Create AmpExperiment component, add top stories experiment to PS articles

src/app/components/AmpExperiment/index.test.tsx

@@ -0,0 +1,86 @@
+import React from 'react';
+import { render, waitFor } from '../react-testing-library-with-providers';
+import AmpExperiment from './index';
+
+const experimentConfig = {
+  someExperiment: {
+    variants: {
+      control: 33,
+      variant_1: 33,
+      variant_2: 33,
+    },
+  },
+};
+
+const multipleExperimentConfig = {
+  aExperiment: {
+    variants: {
+      control: 33,
+      variant_1: 33,
+      variant_2: 33,
+    },
+  },
+  bExperiment: {
+    variants: {
+      control: 33,
+      variant_1: 33,
+      variant_2: 33,
+    },
+  },
+};
+
+describe('Amp experiment container on Amp pages', () => {
+  it('should render an amp-experiment with the expected config', async () => {
+    const { container } = render(
+      <AmpExperiment experimentConfig={experimentConfig} />,
+    );
+    expect(container.querySelector('amp-experiment')).toBeInTheDocument();
+    expect(container).toMatchInlineSnapshot(`
+    <div>
+      <amp-experiment>
+        <script
+          type="application/json"
+        >
+          {"someExperiment":{"variants":{"control":33,"variant_1":33,"variant_2":33}}}
+        </script>
+      </amp-experiment>
+    </div>
+    `);
+  });
+
+  it('should render an amp-experiment with the expected config when multiple experiments are running at the same time', async () => {
+    const { container } = render(
+      <AmpExperiment experimentConfig={multipleExperimentConfig} />,
+    );
+    expect(container.querySelector('amp-experiment')).toBeInTheDocument();
+    expect(container).toMatchInlineSnapshot(`
+      <div>
+        <amp-experiment>
+          <script
+            type="application/json"
+          >
+            {"aExperiment":{"variants":{"control":33,"variant_1":33,"variant_2":33}},"bExperiment":{"variants":{"control":33,"variant_1":33,"variant_2":33}}}
+          </script>
+        </amp-experiment>
+      </div>
+    `);
+  });
+
+  it(`should add amp-experiment extension script to page head`, async () => {
+    render(<AmpExperiment experimentConfig={experimentConfig} />);
+
+    await waitFor(() => {
+      const scripts = Array.from(document.querySelectorAll('head script'));
+
+      expect(scripts).toEqual(
+        expect.arrayContaining([
+          expect.objectContaining({
+            src: `https://cdn.ampproject.org/v0/amp-experiment-0.1.js`,
+          }),
+        ]),
+      );
+
+      expect(scripts).toHaveLength(1);
+    });
+  });
+});

src/app/components/AmpExperiment/index.tsx

@@ -0,0 +1,50 @@
+/** @jsx jsx */
+/* @jsxFrag React.Fragment */
+import { jsx } from '@emotion/react';
+import React from 'react';
+import { Helmet } from 'react-helmet';
+
+type Variant = string;
+type Experiment = string;
+type TrafficAllocationPercentage = number;
+
+type AmpExperimentConfig = {
+  [key: Experiment]: {
+    sticky?: boolean;
+    consentNotificationId?: string;
+    variants: {
+      [key: Variant]: TrafficAllocationPercentage;
+    };
+  };
+};
+
+type AmpExperimentProps = {
+  [key: Experiment]: AmpExperimentConfig;
+};
+
+const AmpHead = () => (
+  <Helmet>
+    <script
+      async
+      custom-element="amp-experiment"
+      src="https://cdn.ampproject.org/v0/amp-experiment-0.1.js"
+    />
+  </Helmet>
+);
+
+const AmpExperiment = ({ experimentConfig }: AmpExperimentProps) => {
+  return (
+    <>
+      <AmpHead />
+      <amp-experiment>
+        <script
+          type="application/json"
+          /* eslint-disable-next-line react/no-danger */
+          dangerouslySetInnerHTML={{ __html: JSON.stringify(experimentConfig) }}
+        />
+      </amp-experiment>
+    </>
+  );
+};
+
+export default AmpExperiment;

src/app/components/AmpExperiment/types.d.ts

@@ -0,0 +1,7 @@
+declare namespace JSX {
+  interface IntrinsicElements {
+    'amp-experiment': React.PropsWithChildren<
+      ScriptHTMLAttributes<HTMLScriptElement>
+    >;
+  }
+}

src/app/pages/ArticlePage/ArticlePage.styles.ts

@@ -81,8 +81,7 @@ export default {
         paddingBottom: `${spacings.QUADRUPLE}rem`,
       },
     }),
-
-  topStoriesAndFeaturesSection: ({ spacings, mq }: Theme) =>
+  featuresSection: ({ spacings, mq }: Theme) =>
     css({
       marginBottom: `${spacings.TRIPLE}rem`,
 
@@ -91,4 +90,21 @@ export default {
         padding: `${spacings.DOUBLE}rem`,
       },
     }),
+  topStoriesSection: ({ spacings, mq }: Theme) =>
+    css({
+      marginBottom: `${spacings.TRIPLE}rem`,
+      [mq.GROUP_4_MIN_WIDTH]: {
+        display: 'block',
+        marginBottom: `${spacings.FULL}rem`,
+        padding: `${spacings.DOUBLE}rem`,
+      },
+      '[amp-x-topStoriesExperiment="show_at_halfway"] &': {
+        display: 'none',
+        [mq.GROUP_4_MIN_WIDTH]: {
+          display: 'block',
+          marginBottom: `${spacings.FULL}rem`,
+          padding: `${spacings.DOUBLE}rem`,
+        },
+      },
+    }),
 };

src/app/pages/ArticlePage/ArticlePage.tsx

@@ -59,20 +59,26 @@ import {
 import { ServiceContext } from '../../contexts/ServiceContext';
 import RelatedContentSection from '../../components/RelatedContentSection';
 import Disclaimer from '../../components/Disclaimer';
-
 import SecondaryColumn from './SecondaryColumn';
-
 import styles from './ArticlePage.styles';
 import { ComponentToRenderProps, TimeStampProps } from './types';
+import AmpExperiment from '../../components/AmpExperiment';
+import {
+  experimentTopStoriesConfig,
+  getExperimentTopStories,
+  ExperimentTopStories,
+} from './experimentTopStories/helpers';
 
 const ArticlePage = ({ pageData }: { pageData: Article }) => {
-  const { isApp, pageType, service } = useContext(RequestContext);
+  const { isApp, pageType, service, isAmp, id } = useContext(RequestContext);
+
   const {
     articleAuthor,
     isTrustProjectParticipant,
     showRelatedTopics,
     brandName,
   } = useContext(ServiceContext);
+
   const { enabled: preloadLeadImageToggle } = useToggle('preloadLeadImage');
 
   const {
@@ -131,6 +137,16 @@ const ArticlePage = ({ pageData }: { pageData: Article }) => {
     ...(isCPS && { pageTitle: `${atiAnalytics.pageTitle} - ${brandName}` }),
   };
 
+  const topStoriesContent = pageData?.secondaryColumn?.topStories;
+  const { shouldEnableExperimentTopStories, transformedBlocks } =
+    getExperimentTopStories({
+      blocks,
+      topStoriesContent,
+      isAmp,
+      service,
+      id,
+    });
+
   const componentsToRender = {
     visuallyHiddenHeadline,
     headline: headings,
@@ -174,6 +190,10 @@ const ArticlePage = ({ pageData }: { pageData: Article }) => {
       <Disclaimer {...props} increasePaddingOnDesktop={false} />
     ),
     podcastPromo: () => (podcastPromoEnabled ? <InlinePodcastPromo /> : null),
+    experimentTopStories: () =>
+      topStoriesContent ? (
+        <ExperimentTopStories topStoriesContent={topStoriesContent} />
+      ) : null,
   };
 
   const visuallyHiddenBlock = {
@@ -183,8 +203,8 @@ const ArticlePage = ({ pageData }: { pageData: Article }) => {
   };
 
   const articleBlocks = startsWithHeading
-    ? blocks
-    : [visuallyHiddenBlock, ...blocks];
+    ? transformedBlocks
+    : [visuallyHiddenBlock, ...transformedBlocks];
 
   const promoImageBlocks =
     pageData?.promo?.images?.defaultPromoImage?.blocks ?? [];
@@ -206,6 +226,9 @@ const ArticlePage = ({ pageData }: { pageData: Article }) => {
 
   return (
     <div css={styles.pageWrapper}>
+      {shouldEnableExperimentTopStories && (
+        <AmpExperiment experimentConfig={experimentTopStoriesConfig} />
+      )}
       <ATIAnalytics atiData={atiData} />
       <ChartbeatAnalytics
         sectionName={pageData?.relatedContent?.section?.name}

src/app/pages/ArticlePage/SecondaryColumn.tsx

@@ -21,15 +21,12 @@ const SecondaryColumn = ({ pageData }: { pageData: Article }) => {
   return (
     <div css={styles.secondaryColumn}>
       {topStoriesContent && (
-        <div
-          css={styles.topStoriesAndFeaturesSection}
-          data-testid="top-stories"
-        >
+        <div css={styles.topStoriesSection} data-testid="top-stories">
           <TopStoriesSection content={topStoriesContent} />
         </div>
       )}
       {featuresContent && (
-        <div css={styles.topStoriesAndFeaturesSection} data-testid="features">
+        <div css={styles.featuresSection} data-testid="features">
           <FeaturesAnalysis
             content={featuresContent}
             parentColumns={{}}

src/app/pages/ArticlePage/experimentTopStories/helpers.test.tsx

@@ -0,0 +1,109 @@
+import { getExperimentTopStories } from './helpers';
+import { topStoriesList } from '../PagePromoSections/TopStoriesSection/fixture/index';
+
+describe('AMP top stories experiment', () => {
+  const mockTextBlock = {
+    type: 'text',
+    model: {
+      blocks: [],
+    },
+  };
+  const expectedExperimentTopStoriesBlock = (index: number) => {
+    return {
+      type: 'experimentTopStories',
+      model: topStoriesList,
+      id: `experimentTopStories-${index}`,
+    };
+  };
+
+  const blocksShortLength = [mockTextBlock];
+
+  const blocksEvenLength = [
+    mockTextBlock,
+    mockTextBlock,
+    mockTextBlock,
+    mockTextBlock,
+  ];
+  const blocksOddLength = [mockTextBlock, mockTextBlock, mockTextBlock];
+
+  describe('getExperimentTopStories()', () => {
+    it('returns shouldEnableExperimentTopStories as true if props match conditions.', () => {
+      const { shouldEnableExperimentTopStories } = getExperimentTopStories({
+        blocks: blocksEvenLength,
+        topStoriesContent: topStoriesList,
+        isAmp: true,
+        id: 'c6v11qzyv8po',
+        service: 'news',
+      });
+      expect(shouldEnableExperimentTopStories).toBe(true);
+    });
+
+    it.each`
+      testDescription                                | isAmp    | id                | service
+      ${'all props are undefined'}                   | ${false} | ${undefined}      | ${undefined}
+      ${'only isAmp is true'}                        | ${true}  | ${undefined}      | ${undefined}
+      ${'only pathname is undefined'}                | ${true}  | ${undefined}      | ${'news'}
+      ${'only pathname is defined and valid'}        | ${false} | ${'c6v11qzyv8po'} | ${undefined}
+      ${'all props defined but pathname is invalid'} | ${false} | ${'c1231qzyv8po'} | ${undefined}
+      ${'only service is undefined'}                 | ${true}  | ${'c6v11qzyv8po'} | ${undefined}
+      ${'only service is defined and valid'}         | ${false} | ${undefined}      | ${'news'}
+      ${'all props defined but service is invalid'}  | ${true}  | ${'c6v11qzyv8po'} | ${'igbo'}
+    `(
+      'returns shouldEnableExperimentTopStories as false because $testDescription.',
+      ({ isAmp, id, service }) => {
+        const { shouldEnableExperimentTopStories } = getExperimentTopStories({
+          blocks: blocksEvenLength,
+          topStoriesContent: topStoriesList,
+          isAmp,
+          id,
+          service,
+        });
+
+        expect(shouldEnableExperimentTopStories).toBe(false);
+      },
+    );
+
+    const expectedBlocksEvenLength = [
+      mockTextBlock,
+      mockTextBlock,
+      expectedExperimentTopStoriesBlock(2),
+      mockTextBlock,
+      mockTextBlock,
+    ];
+    const expectedBlocksOddLength = [
+      mockTextBlock,
+      expectedExperimentTopStoriesBlock(1),
+      mockTextBlock,
+      mockTextBlock,
+    ];
+
+    it.each`
+      testType  | inputBlocks         | expectedOutput
+      ${'even'} | ${blocksEvenLength} | ${expectedBlocksEvenLength}
+      ${'odd'}  | ${blocksOddLength}  | ${expectedBlocksOddLength}
+    `(
+      'should insert experimentTopStories block into blocks array in the correct position when blocks.length is $testType',
+      ({ inputBlocks, expectedOutput }) => {
+        const { transformedBlocks } = getExperimentTopStories({
+          blocks: inputBlocks,
+          topStoriesContent: topStoriesList,
+          isAmp: true,
+          id: 'c6v11qzyv8po',
+          service: 'news',
+        });
+        expect(transformedBlocks).toEqual(expectedOutput);
+      },
+    );
+
+    it('does not insert experiment top stories blocks if the blocks array length is < 2.', () => {
+      const { transformedBlocks } = getExperimentTopStories({
+        blocks: blocksShortLength,
+        topStoriesContent: topStoriesList,
+        isAmp: true,
+        id: 'c6v11qzyv8po',
+        service: 'news',
+      });
+      expect(transformedBlocks).toBe(blocksShortLength);
+    });
+  });
+});