storybook/code/addons/jest/src/index.ts

import { addons } from 'storybook/internal/preview-api';

import { normalize, sep } from 'upath';

import { ADD_TESTS, defineJestParameter } from './shared';

const findTestResults = (
  testFiles: string[],
  jestTestResults: { testResults: { name: string }[] },
  jestTestFilesExt: string
) =>
  Object.values(testFiles).map((name) => {
    const fileName = `${sep}${name}${jestTestFilesExt}`;

    if (jestTestResults && jestTestResults.testResults) {
      const fileNamePattern = new RegExp(fileName);

      return {
        fileName,
        name,
        result: jestTestResults.testResults.find((test) =>
          Boolean(normalize(test.name).match(fileNamePattern))
        ),
      };
    }

    return { fileName, name };
  });

interface EmitAddTestsArg {
  kind: string;
  story: () => void;
  testFiles: string[];
  options: {
    results: { testResults: { name: string }[] };
    filesExt: string;
  };
}

const emitAddTests = ({ kind, story, testFiles, options }: EmitAddTestsArg) => {
  addons.getChannel().emit(ADD_TESTS, {
    kind,
    storyName: story,
    tests: findTestResults(testFiles, options.results, options.filesExt),
  });
};

export const withTests = (userOptions: { results: any; filesExt?: string }) => {
  const defaultOptions = {
    filesExt: '((\\.specs?)|(\\.tests?))?(\\.[jt]sx?)?$',
  };
  const options = { ...defaultOptions, ...userOptions };

  return (...args: any[]) => {
    const [storyFn, { kind, parameters = {} }] = args;
    const testFiles = defineJestParameter(parameters);

    if (testFiles !== null) {
      emitAddTests({ kind, story: storyFn, testFiles, options });
    }

    return storyFn();
  };
};