 <p>I have several test cases in a test suite and before I was running the test suite in the Mac Terminal like this: </p> <pre><code>python LoginSuite.py </code></pre> <p>Running the command this way my directory was being populated with .pyc files. I tried the below stated method and it solved the issue:</p> <pre><code>python -B LoginSuite.py </code></pre> <p>This method works if you are importing test cases into the test suite and running the suite on the command line. </p>