catala/tests/README.md

Catala test suite

This folder contains Catala source files designed to test the features of the language.

It uses make pass_tests to launch tests and compare the test terminal output with an expected output.

Expected outputs are stored using the convention <name_of_test>.catala_<language>.<name_of_scope>.out in the corresponding test output folder.

For both workflows: use CATALA_OPTS="..." make ... to pass in Catala compiler options when debugging.

Workflow for adding new tests

1. Create a new test file in foo/{good,bad}/bar.catala_<language> (pick the right directory and an informative name for your test)
2. Write your test, and pick a toplevel scope A to run.
3. From this directory, launch make foo/{good,bad}/bar.catala_<language>.A.run to get the output of your test.
4. When you're happy with the output, launch make foo/{good,bad}/bar.catala_<language>.A.in. This will record the content of the output of your test into a file.
5. Check that your test pass with make foo/{good,bad}/output/bar.catala_<language>.A.out.
6. That's it, you've added a new test for the Catala language!

Workflow for fixing regressions

1. Run make, if a test fails you should see something like [FAIL foo/{good,bad}/output/bar.catala_<language>.A].
2. Compare the computed and expected output with make foo/{good,bad}/output/bar.catala_<language>.A.out.
3. Debug the compiler and/or the test, running make foo/{good,bad}/bar.catala_<language>.A.run periodically to check the output of Catala on the test case.
4. When you're finished debugging, record the new test output with make foo/{good,bad}/bar.catala_<language>.A.in.
5. Re-run make to check that everything passes.
6. That's it, you've fixed the Catala test suite to adapt for changes in the language.

If a compiler change causes a lot of regressions (error message formatting changes for instance), you can mass-reset the expected the outputs with make reset_tests. Caution: use at your own risk, regressions should be fixed one by one in general.