Running test-storybook does not seem to see .stories.mdx files, only .stories.js files.

[KennethSlade]

Discussed in #18718

^{Originally posted by KennethSlade July 14, 2022}
When I run test-storybook in version 6.5.9, I only see my *.stories.js files get run and pass. I don't see any of my .stories.mdx files, even though stories are specified in main.js as both being valid:

module.exports = {
  stories: ["../src/**/*.stories.mdx", "../src/**/*.stories.@(js|jsx|ts|tsx)"],
...

Storybook packages from package.json:

    "@storybook/addon-actions": "^6.5.9",
    "@storybook/addon-docs": "^6.5.9",
    "@storybook/addon-essentials": "^6.5.9",
    "@storybook/addon-interactions": "^6.5.9",
    "@storybook/addon-links": "^6.5.9",
    "@storybook/jest": "^0.0.10",
    "@storybook/react": "^6.5.9",
    "@storybook/test-runner": "^0.4.0",
    "@storybook/testing-library": "^0.0.13",
    "@storybook/testing-react": "^1.3.0",

Output looks like:

npm test

> my-storybook@0.5.2 test
> test-storybook --url http://localhost:4000

 PASS   browser: chromium  src/artifacts/xxxxxxx.stories.js
 PASS   browser: chromium  src/artifacts/yyyyyyy.stories.js

Test Suites: 2 passed, 2 total
Tests:       6 passed, 6 total
Snapshots:   0 total
Time:        5.024 s
Ran all test suites.

I have about 10 .stories.mdx files that aren't being picked up. Most of my stories in those files have play added to the Story elements, and the interaction tests work in the browser, which is okay, but I was hoping to see them execute with test-storybook for CI purposes.

Am I missing a configuration option or something or is this a bug?

[KennethSlade]

I found a workaround here using the buildStoriesJson feature flag in main.js and then running test-storybook with the --stories-json flag.