Test suite fails to execute when 2 test classes of the same name exist in diff files.

[hopsoft]

1. Create a simple test suite
2. Name one file example_test.rb and the class ExampleTest
3. Name another file junk_test.rb and the class ExampleTest

MicroTest will only retain one of the file paths because they are stored in a Hash keyed on the class name.

Detect this scenario and warn the user.