[new rule] no-snapshots

[cartogram]

Wondering if I could contribute this no-snapshots rule that I wrote for Shopify

[SimenB]

For sure, I bet more people would like to use it. Thanks!

[benmonro]

this is already supported by just setting the maxSize to zero on no-large-snapshots

[NullDivision]

What about a parameter that would still allow snapshots as long as other non-snapshot assertions are present? I'm not completely against snapshots as a guide to how stuff should look overall but I am against them if there are no assertions for actual elements.

[github-actions]

🎉 This issue has been resolved in version 23.11.0 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

Your semantic-release bot 📦🚀

[markogresak]

this is already supported by just setting the maxSize to zero on no-large-snapshots

@benmonro I was hoping for that, but it's not true.

Here are the problems:

1. We have to set up linting of .snap files. In multi-project workspaces, like one managed by Nx, it can be tedious to correctly configure each new project (e.g. a simple lib module). I don't want to chase after developers to fix the config.
2. The feedback cycle is too long. I want the devs who use ESLint editor integration to see the error on toMatchSnapshot while they are writing the test, not after running the test to generate the .snap file and then having to run eslint to spot the error.
3. The error message does not explain the problem at all, so it can be confusing to other developers.
   The config:

   "rules": {
     "jest/no-large-snapshots": ["error", { "maxSize": 0 }]
   }
   

   Error reported by ESLint:

   3:1  error  `103`s should begin with lowercase  jest/no-large-snapshots
   

   Is that a bug in the code? The error is better with { "maxSize": 1 }:

   3:1  error  Expected Jest snapshot to be smaller than 1 lines but was 103 lines long  jest/no-large-snapshots
   

I believe the no-snapshots rule serves a different rule than no-large-snapshots. It forbids the usage of toMatchSnapshot, while no-large-snapshots allows snapshot testing, but moderates the snapshot size.

For reference, the URL to docs linked by @cartogram above is broken, it should be this: https://github.com/Shopify/web-configs/blob/main/packages/eslint-plugin/docs/rules/jest/no-snapshots.md

@benmonro would you consider reopening this issue and adding no-snapshots rule? I'm happy to pick up the development work and send a PR if @cartogram is not around to do it.

[G-Rath]

@markogresak it was actually me who closed the issue, via implementing no-restricted-matchers (#575) which'll let you do exactly what you want :)

[markogresak]

Thanks for a quick answer, on a Sunday no less!

I have completely missed that part since I was focused on disallowing snapshot matching.

For anyone else looking for this, here's how to set it up to work exactly like the no-snapshots rule:

"jest/no-restricted-matchers": [
  "error",
  {
    "toMatchSnapshot": "Do not use toMatchSnapshot or related methods that generate jest snapshots.",
    "toMatchInlineSnapshot": "Do not use toMatchInlineSnapshot or related methods that generate jest snapshots.",
    "toThrowErrorMatchingSnapshot": "Do not use toThrowErrorMatchingSnapshot or related methods that generate jest snapshots.",
    "toThrowErrorMatchingInlineSnapshot": "Do not use toThrowErrorMatchingInlineSnapshot or related methods that generate jest snapshots."
  }
]

[benmonro]

Bless you for banning snapshot tests. Are they even tests at all?

[markogresak]

I would say not really 😄 I see it as an lazy alternative to explicitly matching for the expected properties. The latter takes a bit more time, but it's easier for future devs to read and understand the assertions.

[benmonro]

I found them to even be counter productive. Make a small change and break 50 unrelated snapshot tests. Then you either -u or waste time chasing ghosts