Unify Native and Core behaviour

[ilyapuchka]

Resolves #124

There are currently several differences in behaviour of "Native" and "Core" scenarios:

• native scenarios are executed in order. This may encourage to make scenarios dependent on each other, which is widely considered as a bad practice
• in case of duplicated steps native scenarios raise exception while core scenarios just pick the first step declaration. We can chose to not allow them in core too but anyway behaviour should be the same as in native.
• each example in native tests results in separate "runtime" XCTestCase. This makes it harder to guess the name of the test to run it separately via xcodebuild test with -only-testing parameter.

It would be better if "native" and "core" behave similarly, especially if we are moving in the direction of generating "core" tests from "native" tests.

[deanWombourne]

This looks great, apart from the fact it directly contradicts #35 :( @smaljaar Can you remember why you had a requirement for the sorting of native tests?

[ilyapuchka]

@deanWombourne yes it does contradict that change but I think it encourages a bad practice (we actually do have such tests which rely on the order of execution and fail when run separately). Also I think cucumber itself does not guarantee tests order and that's made on purpose.

[deanWombourne]

@ilyapuchka I agree - tests shouldn't really on each other. However, I'm loath to change this without at least knowing why we were asked to implement it.

Also, looking at cucumber, it's default behaviour is what we have implemented at the moment (i.e. scenarios are run in the order they are found in the feature file) and while I agree or disagree with that, one of the guides I use when deciding what to do is 'what does cucumber do'!

[smaljaar]

This looks great, apart from the fact it directly contradicts #35 :( @smaljaar Can you remember why you had a requirement for the sorting of native tests?

Yes, if I remember correctly at the time I was working on a project with feature parity between iOS and Android. On Android we were using Cucumber and I noticed the order of execution was different between platforms (for some reason iOS was sorting them backwards, but that got fixed in PR #35).

I agree with @ilyapuchka that we should avoid (aiding in) transferring state between tests, but on the other hand it is also just natural and cucumber like to run the examples/scenarios as they are specified. Even if you remove sorting XCTest will still execute the tests in alphabetical order, I think, unless you explicitly add scrambling logic to avoid that.

Actually, there is a new feature to randomise the execution order of tests in Xcode, maybe you could use that feature to remove the ordering instead of removing it from the XCTest-Gherkin lib all together @ilyapuchka ?

[ilyapuchka]

Actually, there is a new feature to randomise the execution order of tests in Xcode, maybe you could use that feature to remove the ordering instead of removing it from the XCTest-Gherkin lib all together

I'm not sure that will work with tests created at runtime (from native feature files).
Another issue is that it is currently using indexes in runtime test names which makes it harder to invoke particular scenario from command line using testing-only option as you need to guess the order of the scenario in the feature file to get its name correctly.
In the end it leads to inconsistencies in behaviour between two kinds of test that may be puzzling when users are migrating from one type of tests to another.