Implement Testing Strategy

[Bombardier-C-Kram]

Implement testing for the Dyalog/OpenAPI project. At this current stage, it's unclear how best to approach testing, and it may be difficult given the state of development. There are likely two main areas that need distinct testing strategies:

1. Testing the C# application: We need to determine appropriate approaches for testing the core application. This could include unit tests, integration tests, or another approach that fits the architecture and features of the C# code.

2. Testing the generated APL: Since the project generates APL code, we need a way to verify that the produced code is correct and robust. Possible strategies could include using a comprehensive OpenAPI spec that exercises all the features we aim to support or constructing unit tests for slices of the generated code.

Open questions:

• Are there existing OpenAPI specifications available that exercise all desired features for validation purposes?
• Should we lean more towards full integration/spec-file-based tests or start with focused unit tests?
• What frameworks or tools are available/appropriate for C# and APL testing?

This issue can serve as a discussion and planning space for implementing the needed tests for both components.