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Troubleshooting errors

This is a list of commonly encountered problems, known issues, and their solutions.


Build failure due to reduced code coverage

YourBase Test Acceleration is designed to avoid test runs that do not need to be executed. The percentage covered may appear lower than what is actually covered as a result. If your CI is configured to fail a build based on the percentage covered, you may need to reconfigure this feature, or check if YourBase Test Acceleration supports filling of missing coverage data with data from previous runs on your code coverage tool.

Selecting specific tests causes incorrect skips

If you swap between explicitly running different but overlapping sets of tests, e.g.

pytest a b
pytest b c
pytest a b

YourBase’s cache will become poisoned. The results from a will be carried through the second run to the third and assumed to be up-to-date, but if you edited a’s dependencies between the first and second run then YourBase will not see these edits.

You can prevent this behavior by always passing YourBase the same set of tests—ideally everything—and letting it choose on its own which to run. If you cannot or did not do this, you can work around this issue by purging the cache before changing which set of tests you run:

rm -rf ${XDG_CACHE_HOME:-~/.cache}/yourbase

Unittest setUp or tearDown overrides lead to incorrect test skipping

If you are using unittest and define your own setUp or tearDown functions, be sure they call super before performing other actions:

class MyTestClass:
   def setUp(self):
      super(self.__class__, self).setUp()
      # ...

   def tearDown(self):
      super(self.__class__, self).tearDown()
      # ...

If you are not defining your own setUp and tearDown functions, you don’t need to do this.

__sqlite3 module not found

If you run into errors about the _sqlite3 module not being found, follow the below steps:

  1. Install sqlite3

  2. Rebuild and reinstall the Python version you are using. If you use pyenv, this will look something like:

pyenv install --force <PYTHON_VERSION>

If the above step doesn’t work, try:

pyenv install --force <PYTHON_VERSION>

Incompatibility with Apple machines having the M1 chip

YourBase Test Acceleration doesn’t currently support Apple machines running the M1 chip. This is on our roadmap. If this is causing an issue for you, please reach out to us at

Conflict with proxy objects

Python objects that opaquely wrap other objects by overriding Python builtins like name and class can cause tracing issues in YourBase Test Acceleration that may manifest as errors from within those proxy objects. If you experience these issues, you can set to use a slower tracing algorithm that should avoid these errors.

export YOURBASE_TIMID=true

Note that this since flag dramatically increases the tracing overhead, so we don’t recommend setting this if you are not experiencing issues.

Conflict with plugin pytest-xdist

YourBase Test Acceleration and pytest-xdist plugins have similar goals, reducing the overall test execution time of tests, but take different approaches to solving the problem. When they’re both enabled, there are conflicts. When you’re using YourBase Test Acceleration, please uninstall pytest-xdist or execute pytest-xdist with NUMCPUS=0.

Cache poisoning

YourBase’s acceleration cache can be poisoned when using command-line options to manually select tests (e.g. pytest path/to/ or pytest -k name_of_test). If a change causes another test to “want” to run but the test isn’t selected by pytest, it will not be queued up to run next time it is.

To work around this issue, blow away the YourBase cache before you change which tests you want to manually run:

pytest path/to/a/
rm -rf ~/.cache/yourbase # Run before changing pytest args
pytest path/to/a/different/