MESC Tests

A language-agnostic set of tests is used to check whether each MESC implementation is compliant with the MESC specification.


  1. Install pytest with pytest-xdist: pip install pytest pytest-xdist

  2. Go to the tests directory: cd $MESC_REPO/mesc/tests

  3. Run one of these commands:

run testspytest
run test in parallel mode (much faster)pytest -n auto
run tests in debug mode (helpful for debugging)pytest --pdb
run tests only tests that previously failedpytest --lf
run tests for specific adapters onlypytest --adapters adapters/python adapters/cli

By default, tests will run for all MESC implementations. If you do not have all of these implementations installed, you will need to use --adapters to select only the subset that that you have installed.


Each MESC implementation has an adapter that receives a test as input and prints the result as output. Adapters are located in the adapters directory.

To make a custom adapter:

  1. adapter should be a script that takes a JSON MescQuery as its single argument
  2. the adapter should run the query, and then print the result as JSON
  3. if the config loading or the query fails, simply print the word FAIL

The adapter should never crash upon failure, just print the word FAIL


  • adapters/ contains a test adapter for each MESC implementation
  • configuration file for pytest
  • generates all of the MESC test cases
  • packages MESC tests into form usable by pypi