pytest-sherlock

Pytest plugin which help to find coupled tests.

Sometimes we have coupled tests which depend from ordering

For example:

• PASSES tests/exmaple/test_all_read.py tests/exmaple/test_b_modify.py tests/exmaple/test_c_delete.py
• FAILED tests/exmaple/test_c_delete.py tests/exmaple/test_b_modify.py tests/exmaple/test_all_read.py

In this case pretty simple to detect coupled tests, but if we have >=1k tests which called before it will hard

Content:

• install
• how to use
• waiting in the future

Install

pip install pytest-sherlock

how to use:

pytest tests/exmaple/test_c_delete.py tests/exmaple/test_b_modify.py tests/exmaple/test_all_read.py --flaky-test="test_read_params" -vv

Plugin didn't run all tests, it try to find some possible guilty test and will run first

======================= test session starts =======================
collected 10 items                                                                                                                                                                                  
Try to find coupled tests
Step #1:
tests/exmaple/test_b_modify.py::test_modify_random_param PASSED                                                                                                                               [ 20%]
tests/exmaple/test_c_delete.py::test_delete_random_param PASSED                                                                                                                               [ 40%]
tests/exmaple/test_c_delete.py::test_deleted_passed PASSED                                                                                                                                    [ 60%]
tests/exmaple/test_c_delete.py::test_do_not_delete PASSED                                                                                                                                     [ 80%]
tests/exmaple/test_all_read.py::test_read_params COUPLED                                                                                                                                      [100%]
Step #2:
tests/exmaple/test_b_modify.py::test_modify_random_param PASSED                                                                                                                               [ 33%]
tests/exmaple/test_c_delete.py::test_delete_random_param PASSED                                                                                                                               [ 66%]
tests/exmaple/test_all_read.py::test_read_params COUPLED                                                                                                                                      [100%]
Step #3:
tests/exmaple/test_b_modify.py::test_modify_random_param PASSED                                                                                                                               [ 50%]
tests/exmaple/test_all_read.py::test_read_params COUPLED                                                                                                                                      [100%]

======================== found coupled in 0.08 seconds ========================
found coupled tests: 
         - tests/exmaple/test_b_modify.py::test_modify_random_param
         - tests/exmaple/test_all_read.py::test_read_params

pytest -l -vv tests/exmaple/test_b_modify.py::test_modify_random_param tests/exmaple/test_all_read.py::test_read_params
_____________________________ test_read_params __________________________________

config = {'a': 1, 'b': 13, 'c': 3}, param = 'b'

    def test_read_params(config, param):
>       assert config.get(param) == 2
E       AssertionError: assert 13 == 2
E        +  where 13 = <built-in method get of dict object at 0x107c464b0>('b')
E        +    where <built-in method get of dict object at 0x107c464b0> = {'a': 1, 'b': 13, 'c': 3}.get

tests/exmaple/test_all_read.py:8: AssertionError
======================= 7 passed, 3 coupled in 0.08 seconds ======================= 

TODO

I have a couple ideas, how to improve finder coupled tests:

• use AST for detect common peace of code (variables, functions, etc...)
• Also need to add tests for it =)