Enhance Test System

[ghost]

Tasks

(draft)

• [ ] Split down larger test files into separate files
• [ ] Separate unit and integration tests
• [ ] Provide Mock and Real Integration test

Requirements

• Ensure that existent test-mechanisms are reused
• Ensure that test-system can be reused

(affects #11, but is out of its scope. Should be provided in future)

[ghost]

moved to #20