E fixture ‘mocker’ not found - Travis - GitHub

Today, I was trying to run the tests of my GitHub repository using Travis and I got this error:

E fixture ‘mocker’ not found        

I had no idea what was happening because I was running the tests locally and everything was fine.

Just in case, if it happens to you locally, you can fix it by installing pytest-mock:

pip install pytest-mock        

But in my case, it was happening on Travis. Travis installs the dependencies from the "requirements.txt" file if it is founded, not from other files such as "requirements-dev.txt". It was my case! How do you think I could fix it? Just add to ".travis.yml" the following line:

install

  - pip install -r requirements-dev.txt:        

Happy testing!