Cypress 12.5.1 - Performance - How can one test slow down all the next tests ?

[franck-grenier]

Hello Cypress,
I'm having a strange behaviour with my Cypress 12.5.1 tests in my Gitlab CI.

I have identified a faulty test in my tests suite which, when included, slows down all the following ones.

Before the faulty one, the first tests run in few seconds. After the faulty one, the remaining tests last about 1min.

If I remove the faulty test, they all run fast. If I just skip it, the following ones slow down.

Also, I have to mention that I do not have the problem in my local GUI runner. It happens only in my Gitlab CI runners.

Do you have any idea ?

Thanks

[franck-grenier]

Hello,
after investigating, it looks like the test coverage report take a long time to generate. The report is made by Istanbul (NYC).

When I record the video of the test, I can see it reaches its last assertion and then waits for ~50s more to end successfully. The last action triggered is the coverage report generation but I have no status during this action.

The faulty test interacts with CKeditor which comes pre-build from my assets. And this pre-build CKeditor is a very large file. So, my hypothesis is that NYC takes a long time to parse this pre-build CKeditor file to report test coverage.

I've tried to exclude the whole assets folder from NYC but it keeps inspecting it to produce its coverage report.

[franck-grenier]

Hello,
might be useful for someone.

It was indeed the coverage report parsing CKeditor asset large file which took long time.

I excluded this asset from test coverage and my tests are now super fast.

See NYC Configuration below in package.json :

{
  "dependencies": {
   ...
  },
  "devDependencies": {
    ...
  },
  "nyc": {
    "exclude": ["assets/**"]
  }
}