Add a noMatchSnapshots option.

[tmeasday]

See (storybook-eol/storyshots#93).

Issue:

The idea is that early on in a project, when things are changing a lot, snapshot tests are not particularly useful, but it's still helpful to "smoke test" all stories to ensure they run without error.

What I did

I added a noMatchSnapshots option to just setup a test that runs each story, without checking snapshots.

How to test

1. Create a project, install storyshots but pass initStoryshots({ noMatchSnapshots: true }).
2. Add a story, run jest. Should pass.
3. Change the component's output, run jest again. Should still pass
4. Make the component error in the render function, run jest again. Should fail.

Notes:

Perhaps it would make sense to just allow passing a custom test function, to cover off cases like this and storybook-eol/storyshots#76? Then storyshots is more of a generic tool to integrate storybook with Jest.

initStoryshots({
  test(renderedStory) {
     // In my case, just render without looking at the result
     renderer.create(renderedStory).toJSON()

     // For #76, shallow render + snapshot
     const tree = shallowToJson(shallow(renderedStory))
     expect(tree).toMatchSnapshot()
  }
});

[shilman]

@tmeasday What do you think about creating an option compareSnapshots that defaults to true? I don't like the double negative of noMatchSnapshots. Or just call the option you added skipComparison?

[shilman]

@tmeasday FWIW, I prefer your genericized solution to the current proposal.

[shilman]

I'm having problems testing out the change. It's probably unrelated to your change. What I did:

cd storybook
npm install
cd packages/storyshots
npm link .
cd ../../examples/cra-storybook
npm link storyshots
emacs src/storyshots.tests.js
npm run test

With the following contents for storyshots.tests.js:

import initStoryshots from 'storyshots'
initStoryshots({ noMatchSnapshots: true })

I get the error:

  ● Test suite failed to run

    Cannot find module 'react-test-renderer' from 'index.js'
      
      at Resolver.resolveModule (node_modules/jest-resolve/build/index.js:151:17)
      at Object.<anonymous> (../../../../../.nvm/versions/node/v6.2.1/lib/node_modules/storyshots/dist/index.js:13:26)
      at Object.<anonymous> (src/storyshots.test.js:1:173)

I tried npm i -D react-test-renderer to add the peer dependency, but still get the same error.

I suspect this is related to Lerna. @tmeasday @ndelangen @aaronmcadam. Any help would be much appreciated.

[ndelangen]

I'd name this autoUpdate and have it default value be false.

But I'm not really feeling much for this feature myself, since updating snapshots is real easy already anyway.

[tmeasday]

I'm having problems testing out the change

Apologies, I didn't test the changes on the monorepo. My bad. Let me have a go at it and I'll ping you when I figure it out.

[tmeasday]

I'd name this autoUpdate and have it default value be false.

But I'm not really feeling much for this feature myself, since updating snapshots is real easy already anyway.

@ndelangen -- the idea isn't to update the snapshots, it's to "smoke test" your stories but not to snapshot them.

When you are early in development, pretty much every commit changes your snapshots, and so (in my experience) you tend to disable snapshot tests as they are too noisy. However it's pretty useful to know if a commit has broken a component (in the sense that it fails to render for some story). That's the idea of this change.

@shilman -- I tend to agree that we should do the more generic thing.

[tmeasday]

I rebased this onto #971

Should be easy to test now @shilman.

Haven't changed the API yet though, LMK if it works for you and I'll look at that.

[tmeasday]

Closing this in favour of #1034, simple PR to follow