Add Test-Suite & tests for test-framework components

[fatuhoku]

test-framework itself (core) has some tests, but doesn't declare the tests as a Test-Suite in the test-framework.cabal file.

This issue is concerned with widening test coverage of the codebase.

Tests would make it much easier for contributors-to-be to contribute, as it enables TDD and we can prevent regressions from happening when changes are made.

The test-suite can be made to depend on previous versions (e.g. v0.7) of test-framework itself for convenience of running tests.