2.0.0 - Less boilerplate & full `pytest` alignment

I am very pleased to announce this new version of pytest-cases, providing a lot of major improvements. Creating powerful and complex test suites have never been so easy and intuitive !

Below is a complete list of changes, but the user guide has also been updated accordingly so feel free to have a look to get a complete example-based walkthrough.

A/ More powerful and flexible cases collection

New @parametrize_with_cases decorator to replace @cases_data (deprecated).

1. Aligned with pytest:

   • now argnames can contain several names, and the case functions are automatically unpacked into it. You don't need to perform a case.get() in the test anymore !

       @parametrize_with_cases("a,b")
       def test_foo(a, b):
           # use a and b directly !
           ...
     

   • cases are unpacked at test setup time, so the clock does not run while the case is created - in case you use pytest-harvest to collect the timings.

   • @parametrize_with_cases can be used on test functions as well as fixture functions (it was already the case in v1)

2. Easier to configure:

   • the decorator now has a single cases argument to indicate the cases, wherever they come from (no module argument anymore)

   • default (cases=AUTO) automatically looks for cases in the associated case module named test_xxx_cases.py. Users can easily switch to alternate pattern cases_xxx.py with cases=AUTO2. Fixes #91.

   • cases can sit inside a class, like what you're used to do with pytest. This additional style makes it much more convenient to organize cases and associated them with tests, when cases sit in the same file than the tests. Fixes #93.

   • an explicit sequence can be provided, it can mix all kind of sources: functions, classes, modules, and module names as strings (even relative ones!).

      @parametrize_with_cases("a", cases=(CasesClass, '.my_extra_cases'))
      def test_foo(a):
          ...
     

3. More powerful API for filtering:

   • a new prefix argument (default case_) can be used to define case functions for various type of parameters: welcome user_<id>, data_<id>, algo_<id>, model_<id> ! Fixes #108

   • a new glob argument receiving a glob-like string can be used to further filter cases based on their names. For example you can distinguish *_success from *_failure case ids, so as to dispatch them to the appropriate positive or negative test. Fixes #108

   • finally you can still use has_tag and/or provide a filter callable, but now the callable will receive the case function, and this case function has a f._pytestcase attribute containing the id, tags and marks - it is therefore much easier to implement custom filtering.

B/ Easier-to-define case functions

• Case functions can start with different prefixes to denote different kind of data: e.g. data_<id>, user_<id>, model_<id>, etc.

• Case functions can now be parametrized with @parametrize or @pytest.mark.parametrize, just as in pytest ! This includes the ability to put pytest marks on the whole case, or on some specific parameter values using pytest.param. @cases_generator is therefore now deprecated but its alternate style for ids and arguments definition was preserved in @parametrize, see below.

• Now case functions can require fixtures ! In that case they will be transformed into fixtures and injected as fixture_ref in the parametrization. Fixes #56.

• New single optional @case(id=None, tags=(), marks=()) decorator to replace @case_name and @case_tags (deprecated): a single simple way to customize all aspects of a case function. Also, @test_target completely disappears from the picture as it was just a tag like others - this could be misleading.

C/ Misc / pytest goodies

• New aliases for readability: @fixture for @fixture_plus, and@parametrize for @parametrize_plus (both aliases will coexist with the old names). Fixes #107.

• @parametrize was improved in order to support the alternate parametrization mode that was previously offered by @cases_generator, see api reference. That way, users will be able to choose the style of their choice. Fixes #57 and #106.

• @parametrize now raises an explicit error message when the user makes a mistake with the argnames. Fixes #105.

• More readable error messages in @parametrize when lazy_value does not return the same number of argvalues than expected from the argnames.

• Any error message associated to a lazy_value function call is not caught and hidden anymore but is emitted to the user, for easier debugging.

• Fixed issue with lazy_value when a single mark is passed in the constructor.

• lazy_value used as a tuple for several arguments now have a correct id generated even in old pytest version 2.

• New pytest goodie assert_exception that can be used as a context manager. Fixes #104.

See documentation page for details.