Browser: 'firefox' was not found on your system -- but FF is version 57 in container

[jcollum]

Step 7/10 : RUN firefox --version
 ---> Running in d83fe5a77482
Mozilla Firefox 57.0.2
Removing intermediate container d83fe5a77482
 ---> 228be4d907e8
Step 8/10 : RUN apt-cache policy google-chrome-stable
 ---> Running in 0334ad13b1cd
google-chrome-stable:
  Installed: 67.0.3396.87-1
  Candidate: 67.0.3396.87-1
  Version table:
 *** 67.0.3396.87-1 0
        500 http://dl.google.com/linux/chrome/deb/ stable/main amd64 Packages
        100 /var/lib/dpkg/status
Removing intermediate container 0334ad13b1cd
 ---> d90dd9872085
Step 9/10 : RUN $(npm bin)/cypress run --browser firefox
 ---> Running in be8690b2e011
[00:17:23]  Verifying Cypress can run /root/.cache/Cypress/3.0.3/Cypress [started]
[00:17:25]  Verified Cypress!       /root/.cache/Cypress/3.0.3/Cypress [title changed]
[00:17:25]  Verified Cypress!       /root/.cache/Cypress/3.0.3/Cypress [completed]
Can't run because you've entered an invalid browser.

Browser: 'firefox' was not found on your system.

[marcoarruda]

Same issue here
Cypress 4.5.0

Any clues?

[edouard-lopez]

Got same thing with cypress/browsers:node14.16.0-chrome89-ff86

Can't run because you've entered an invalid browser name.

Browser: 'firefox' was not found on your system or is not supported by Cypress.

  test-e2e-firefox:
    runs-on: ubuntu-latest
    container: cypress/browsers:node14.16.0-chrome89-ff86
    steps:
      - name: Checkout code
        uses: actions/checkout@v2
      - name: End-to-end testing
        uses: cypress-io/github-action@v2
        with:
          start: yarn start
          wait-on: "http://localhost:3000"
          browser: firefox
        env:
          NODE_ENV: development

[edouard-lopez]

Just copying the official cypress-io/github-action#firefox,

In order to run Firefox, you need to use non-root user (Firefox security restriction).

name: Firefox
on: push
jobs:
  firefox:
    runs-on: ubuntu-latest
    container:
      image: cypress/browsers:node12.16.1-chrome80-ff73
      options: --user 1001  # <-------------------------
    steps:
      - uses: actions/checkout@v2
      - uses: cypress-io/github-action@v2
        with:
          browser: firefox