Refactor: make integration tests more readable

[bigdaz]

The current integration tests are not very readable, making it a bit difficult to discern exactly what's being tested.
This can be improved by:

• Ensuring test names accurately describe what is being tested
• Extracting verification fixtures so that verification blocks are more concise
• Removing redundant tests (some tests verify aspects of Gradle dependency resolution that are not the purview of this project)