test: add firefox-esr example

[MikeMcC399]

Issue

The Mozilla Firefox browser is currently packaged into Cypress Docker Linux/amd64 images in the repositories cypress/browsers and cypress/included, however the corresponding Linux/arm64 platform images do not include Firefox.

Firefox for Linux/arm64 is not part of the factory build process and it is not documented how to include it in a custom-built Cypress Docker image.

Opportunities

Mozilla plans

As can be seen for instance on https://download-installer.cdn.mozilla.net/pub/firefox/releases/129.0.1/, there is no download directory for Linux on ARM64. This is currently the barrier to integrating Firefox Linux/arm64 into the factory build process.

Mozilla announced Firefox Nightly Now Available for Linux on ARM64 on Apr 19, 2024. Nightly builds do not however conform to the download process used in factory/installScripts/firefox/default.sh. Assuming that Mozilla completes this beta phase and makes Firefox for Linux on ARM64 available on the regular "Rapid Release" channel, then the factory process could be extended - see issue #1190.

Debian packages

Debian Firefox documentation describes that Debian packages include the firefox-esr package

bookworm (stable) (web): Mozilla Firefox web browser - Extended Support Release (ESR)
115.14.0esr-1~deb12u1 [security]: amd64 arm64 armhf i386 mips64el ppc64el s390x

Choosing a Firefox update channel explains the Firefox "Extended Support Release (ESR)" channel and that it receives major updates on average every 52 weeks.

Benefits

Adding an example for Firefox-ESR benefits Cypress Docker users:

1. with arm64 (aka aarch64) processors wanting to test Firefox
2. who need to test against the Firefox "Extended Support Release (ESR)" version instead of a "Rapid Release" version

Change

• Add a sub-directory firefox-esr to the examples directory.
• Provide a working example of installing the Firefox-ESR browser and running it with Cypress.
• Refer to the new examples/firefox-esr directory from the main README and combine the texts together with the Chromium example.

[cypress-app-bot]

• Create a Draft Pull Request if your PR is not ready for review. Mark the PR as Ready for Review when you're ready for a Cypress team member to review the PR.

[MikeMcC399]

I have tested this locally on x86 with Docker Desktop for Linux and Docker Desktop for Windows. I don't personally have macOS or arm64 with Docker Desktop for Mac available to test.

[jennifer-shehane]

I tested it on my Mac, but I don't have arm. We can collect some feedback from others. Shouldn't do much harm to merge.

[MikeMcC399]

@jennifer-shehane

I tested it on my Mac, but I don't have arm. We can collect some feedback from others. Shouldn't do much harm to merge.

Thanks for your test! I agree that there is no harm to merge (so thanks for that!). If something needs tweaking for arm64 we can add it later. Since it is only an example it does not affect the publishing workflow.