`copilot-core`: Increase test coverage

[ivanperez-keera]

Description

The test coverage of copilot-core is currently reported at 25% by Hackage. This is very low.

Although there are exceptions to what we can test (record fields of existential types) or should tests (proxies, automatically generated constructors and accessor functions), the coverage of our tests should be higher and anything that is not tested should be documented.

Type

• Maintenance: Increase coverage of tests.

Additional context

None.

Requester

• Ivan Perez

Method to check presence of bug

Not applicable (not a bug).

Expected result

All top-level functions that are not automatically generated by the compiler are tested, except where testing them is not possible or for code that is automatically generated (constructors, record accessor functions). Anything not tested is documented.

Desired result

All top-level functions that are not automatically generated by the compiler are tested, except where testing them is not possible or for code that is automatically generated (constructors, record accessor functions). Anything not tested is documented.

Proposed solution

Add tests for all definitions in Copilot.Core.Type and Copilot.Core.Type.Array, except record accessor functions.

Further notes

None.

[ivanperez-keera]

Change Manager: Confirmed that the issue exists.

[ivanperez-keera]

Technical Lead: Confirmed that the issue should be addressed.

[ivanperez-keera]

Technical Lead: Issue scheduled for fixing in Copilot 3.19.

Fix assigned to: @ivanperez-keera .

[ivanperez-keera]

Implementor: Solution implemented, review requested.

[ivanperez-keera]

Change Manager: Verified that:

• Solution is implemented:
  • [X] The code proposed compiles and passes all tests. Details: Build log: https://app.travis-ci.com/github/Copilot-Language/copilot/builds/269344778
  • [X] The solution proposed produces the expected result. Details: Evaluated by manual inspection. Running tests with coverage enabled achieves coverage of 97% for top-level definitions (37 out of 38 definitions). The one not tested is uTypeType, which cannot be tested due to being part of an existential type (it's necessity is being discussed in #484). The modules Copilot.Core.Operators and Copilot.Core.Spec and Copilot.Core.Expr only contain datatype definitions, so they do not need to be tested.
• [X] Implementation is documented. Details: New tests are documented.
• [X] Change history is clear.
• [X] Commit messages are clear.
• [X] Changelogs are updated.
• [X] Examples are updated. Details: No updates needed.
• [X] Required version bumps are evaluated. Details: Bump not needed. Changes affect tests only.

[ivanperez-keera]

Change Manager: Implementation ready to be merged.