How do tests work?

[chaojian-zhang]

This starts as a dumb question and later I resolved it myself so I put it here for reference purposes: so every once in a while I re-install UnrealCLR into a new project this confuses me: how does Content/Tests/Tests.umap decide which tests to run?

I checked and it seemed that none of the BlueprintActor, BlueprintSceneComponent, or Level Blueprint (for Tests.umap) is responsible for this, since they didn't make any explicit calls through either FindManagedFunction() or ExecuteManagedFunction() - and it occurred to me it's actually part of the source:

1. What is this ISystem (https://github.com/nxrighthere/UnrealCLR/blob/master/Source/Managed/Tests/Tests.cs)?
2. The Levels' "Test Systems" private variable is actually specifying which test to run, as in https://github.com/nxrighthere/UnrealCLR/blob/master/Source/Managed/Tests/Tests.cs.

[chaojian-zhang]

Notice ISystem is a custom abstraction in User Code. Also see issue #115.