title: How reliable is Tox' caching?
body: <p>I am using Tox as a wrapper around all the python code quality tools like flake8, mypy and pytest. I also invoke Tox from Jenkins.</p>
  
  <p>Currently, for every <code>git push</code> we</p>
  
  <ul>
  <li>create a fresh Conda environment holding python=3.7 and tox</li>
  <li>invoke tox, which will recreate all virtual environments freshly</li>
  <li>remove .tox/ and the Conda environment</li>
  </ul>
  
  <p>Due to this, running tox takes 2 seconds locally but 90 seconds in Jenkins.</p>
  
  <p>I now wonder whether we are to cautious. Would it be ok to leave the .tox/ cache folder alone in Jenkin? It might be important that we have just <code>deps = -rrequirements-dev.txt</code> in <code>[testenv]</code>.</p>
  
  <p>Are there other means to speed up testing with tox?</p>