fix: don't duplicate .gitignore entries

[DerTimonius]

Description

This PR fixes the duplication of existing .gitignore entries while running npm create playwright.

Although this only occurs when the command is run more than once, the added entries don't need to be duplicated.

Related to microsoft/playwright#31021

[DerTimonius]

@microsoft-github-policy-service agree

[hamirmahal]

I was thinking it'd be kind of nice if the entries added by Playwright were separated by a heading, and they were in sorted order.

Something like this, for example

# Playwright
/blob-report/
/playwright-report/
/playwright/.cache/
/test-results/

Maybe these changes can go in this pull request, or I might be able to add them in a separate pull request, later.

[mxschmitt]

I see that our only test-coverage so far is to check if the gitignore file exists. Maybe its time extend it that it contains the content we expect it to have.

Code pointer: https://github.com/microsoft/create-playwright/blob/3b986a1faf4f1d4b853ebbdb94c4c6e109e779b6/tests/integration.spec.ts#L31C41-L31C50

[DerTimonius]

@mxschmitt good idea, I'm currently trying to create a test that runs the script twice, but the second run never finishes:

I was wondering, if there would be any other option to try to run the script twice?

[mxschmitt]

@mxschmitt good idea, I'm currently trying to create a test that runs the script twice, but the second run never finishes:

I was wondering, if there would be any other option to try to run the script twice?

Feel free to push the changes into your branch, if it hangs, I'd be happy to take a look.

[mxschmitt]

Please re-base (since it has merge conflicts), apply comments and then we can merge it. The toMatch wasn't working before, hence it didn't fail on the test-results regex bug.