(Unity) Attribute-based BDD-style tests

[sbergen]

Would look something like

// Example of BDD-style tests
[Feature("Restarting the game")]
public class BddStyleTests : BddTest
{
	[Scenario("The game should be restartable by pressing the trigger key")]
	public IBddStep[] Restart() => new[]
	{
		Given("the player has failed", this.FailTheGame()),
		When("the user presses the trigger key", this.MockTriggerInput()),
		Then("the game should be restarted", this.AssertTheGameHasBeenRestarted())
	};

...
}

...which results in the test runner looking like

...and the state output like:

[.] Scenario: The game should be restartable by pressing the trigger key (Started 0.14 s ≈ 10 frames ago)
  [.] Given the player has failed (Started 0.14 s ≈ 10 frames ago)
    [✓] Trigger miss CONDITION EXPECTED WITHIN 2.00 s (Completed in 0.11 s ≈ 8 frames)
    [✓] WAIT FOR 1 FRAME(S) (Completed in 0.02 s ≈ 2 frames)
    [✓] Trigger miss CONDITION EXPECTED WITHIN 2.00 s (Completed in 0.00 s ≈ 0 frames)
    [.] WAIT FOR 1 FRAME(S) (Started 0.01 s ≈ 0 frames ago)
    [ ] Trigger miss CONDITION EXPECTED WITHIN 2.00 s
    [ ] WAIT FOR 1 FRAME(S)
  [ ] When the user presses the trigger key
    [ ] Mock trigger input
  [ ] Then the game should be restarted
    [ ] Assert restarted

Unity-only, because we don't depend on NUnit in vanilla C#.

TODO:

• Update docs and changelog (docs will be updated separately)
• Put more things in BddTest?
• Implement tests
• Make sure all misuse has proper error messages

[codecov]

Codecov Report

Merging #160 (bafc2e4) into main (21eed71) will not change coverage.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##              main      #160    +/-   ##
==========================================
  Coverage   100.00%   100.00%            
==========================================
  Files           65        83    +18     
  Lines         1059      1438   +379     
  Branches        47        47            
==========================================
+ Hits          1059      1438   +379     

Flag	Coverage Δ
Unity2019.4.14f1	100.00% <100.00%> (?)
Unity2020.3.1f1	100.00% <100.00%> (?)
netstandard	100.00% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
...beatwaves.responsible/Runtime/Bdd/BddTest.Unity.cs	100.00% <100.00%> (ø)
....responsible/Runtime/Bdd/FeatureAttribute.Unity.cs	100.00% <100.00%> (ø)
...responsible/Runtime/Bdd/ScenarioAttribute.Unity.cs	100.00% <100.00%> (ø)
...waves.responsible/Runtime/Context/SourceContext.cs	100.00% <0.00%> (ø)
...sponsible/Editor/TestOperationStatusWindowState.cs	100.00% <0.00%> (ø)
...ible/Runtime/Unity/UnhandledLogMessageException.cs	100.00% <0.00%> (ø)
...es.responsible/Runtime/TestOperationState.Unity.cs	100.00% <0.00%> (ø)
....responsible/Runtime/Unity/UnityFailureListener.cs	100.00% <0.00%> (ø)
com.beatwaves.responsible/Editor/AggregateLabel.cs	100.00% <0.00%> (ø)
...es.responsible/Runtime/Unity/UnityTestScheduler.cs	100.00% <0.00%> (ø)
... and 9 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 21eed71...bafc2e4. Read the comment docs.

[sbergen]

This class is required because AFAIK, NUnit doesn't really support set ups, tear downs etc, if we make it execute a method in any other class. Some discussion here. Also, Unity makes this even more complicated with IEnumerableTestMethodCommand being internal.

[webbertakken]

Looks cool and exciting!

[webbertakken]

Vocabulary feedback:

When looking at this.MockTriggerInput() (also in your opening post), it looks like you're mocking a trigger. But you aren't mocking anything, you're triggering something for real. Now perhaps the thing that's you're triggering is a mock.

I'd argue that in this example it could better be called this.SimulateTriggerKeyInput.

Also; not sure if intended but you're using both "the player" and "the user" for the same actor here, which might not be necessary depending on the language of your team.

[sbergen]

Thanks, that all makes sense!

I should probably review the sample tests as a whole from a consistency and vocabulary perspective.