Storybook + Jest (React specific)

describeStories.tsx

import React from 'react';

import { storiesOf, getStorybook } from '@storybook/react';
import { startCase } from 'lodash';

import { render } from '@testing-library/react';

// from storybook/lib/core/src/client/preview/start.js
function matches(storyKey: string, arrayOrRegex: any) {
  if (Array.isArray(arrayOrRegex)) {
    return arrayOrRegex.includes(storyKey);
  }
  return storyKey.match(arrayOrRegex);
}

// from storybook/lib/core/src/client/preview/start.js
export function isExportStory(
  key: string,
  { includeStories, excludeStories }: any
) {
  return (
    // https://babeljs.io/docs/en/babel-plugin-transform-modules-commonjs
    key !== '__esModule' &&
    (!includeStories || matches(key, includeStories)) &&
    (!excludeStories || !matches(key, excludeStories))
  );
}

// from storybook/lib/router/src/utils.ts
function storyNameFromExport(key: string) {
  return startCase(key);
}

export default function describeStories(stories: any) {
  // from storybook/lib/core/src/client/preview/start.js
  const { default: meta, ...exports } = stories;
  const {
    title: kindName,
    parameters: params,
    decorators: decos,
    component,
  } = meta;

  // filtering out all non-export stories
  const storiesExports = Object.keys(exports).filter(key =>
    isExportStory(key, meta)
  );

  const kind = storiesOf(kindName, stories);
  kind.addParameters({
    framework: 'react', // hardcoding React
    component,
    ...params,
  });

  (decos || []).forEach((decorator: any) => {
    kind.addDecorator(decorator);
  });

  storiesExports.forEach(key => {
    // from storybook/lib/core/src/client/preview/start.js
    const storyFn = exports[key];
    const { name, parameters, decorators } = storyFn.story || {};
    const decoratorParams = decorators ? { decorators } : null;
    const displayNameParams = name ? { displayName: name } : {};
    const storyName = storyNameFromExport(key);

    kind.add(storyName, storyFn, {
      ...parameters,
      ...decoratorParams,
      ...displayNameParams,
    });
  });

  const storybook = getStorybook();

  describe(meta.title, () => {
    const section = storybook.find(x => x.kind === kindName) || { stories: [] };

    test.each(storiesExports)('%s', async key => {
      // Given
      const story = section.stories.find(
        story => story.name === storyNameFromExport(key)
      );

      // When
      if (story) {
        render(<div data-testid="root">{story.render()}</div>);
      } else {
        fail('Story not found');
      }

      // Then
      await expect('[data-testid=root]').toMatchScreenshot();
    });
  });
}