feat: Update tests to match current implementation

[philCryoport]

Originally posted by @Pakisan in #55 (comment)

@philCryoport wrote:

For record's sake, I ran :runPluginVerifier. Result:

BUILD SUCCESSFUL in 11m 3s
17 actionable tasks: 8 executed, 9 up-to-date

Ahem...then decided to RTFM ./gradlew...

Screen output from ./gradlew check
Here's the full output test.zip

This is fine😓

This is so old, that I'm resigned with it. Those tests are checking single scenario - $ref to external file.

At runtime everything is working great, but in test context it fails.

I think that will fix it in parallel with #47, cause it's about digging into JetBrains sdk to fix it