scenarios to return a class and avoid injection into locals

[youtux]

Reading the comment at #310 (comment) (and relative implementation), I figured out that we could make the scenarios(...) function much neater if we made it return a class instead of injecting into the module locals.

For example, given the following feature file:

Feature: My Feature
    Scenario: Scenario 1
    Scenario: Scenario 2
    Scenario: Scenario 3

and the following file:

# test_my_feature.py
from pytest_bdd import scenarios

TestMyFeature = scenarios("my_feature.feature")

and it would be syntactic sugar for the following:

# test_my_feature.py

# Not real code that should be typed, it's just the equivalent version of the file above
from pytest_bdd import scenarios

class TestMyFeature:
    @scenario
    test_scenario_1(): pass

    @scenario
    test_scenario_2(): pass

    @scenario
    test_scenario_3(): pass

This way, if a user needs to override a specific scenario for whatever reason, that could be done easily like this:

# test_my_feature.py
from pytest_bdd import scenarios

class TestMyFeature(scenarios("my_feature.py")):
    @scenario
    test_scenario_3(): pass

I can imagine an stub implementation of scenarios(...) to be something like this:

def scenarios(feature_path):
    ...
    feature = get_feature(feature_path)
    test_cls = type(camel_case(feature.name), (), {})
    for feature in get_features(feature_path):
        for scenario_name, scenario_object in feature.scenarios.items():
            @scenario(feature_path, scenario_name)
            def _scenario(self): pass
            setattr(test_cls, f"test_{snake_case(scenario_name)}", _scenario)
    return test_cls

[youtux]

@elchupanebrej I was inspired to have this change after reading your comment

[elchupanebrej]

Please pay attention, that unittest TestClasses have serious drawbacks when executed by pytest. But there could be special TestClass that could be collected by a specific Collector. I didn't succeed with my first attempts, I'll try to implement another PoC

[jsa34]

@youtux is this still something that you think would be helpful to revisit?

[youtux]

Maybe yes, although I have also get term plan to remove (or at least make optional) the calls to scenarios or @scenario, by instead converting .feature files into test modules themselves. Pytest has an example of how to do that for a YAML file, so I had in mind to follow the same principle.

If we have to put effort into a solution, I'd rather to this one I just mentioned instead.