Add hybrid controller support for mocking

[kibertoad]

Changes

Fix REST+SSE

Checklist

• Apply one of following labels; major, minor, patch or skip-release
• I've updated the documentation, or no changes were necessary
• I've updated the tests, or no changes were necessary

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📝 Walkthrough

Walkthrough

The pull request expands the universal-testing-utils mocking library to support dual-mode contracts that serve either JSON or Server-Sent Events (SSE) responses based on the client's Accept header. Changes include updates to MockttpHelper and MswHelper to accept DualModeContractDefinition contracts, conditional response routing based on the incoming request's Accept header (returning 503 when the header doesn't match the mock's mode), new test contracts with path parameters, comprehensive test coverage for the dual-mode routing behavior, and documentation clarifying the Accept header matching rules and simultaneous use of both response types on the same endpoint.

Estimated code review effort

🎯 4 (Complex) | ⏱️ ~45 minutes

🚥 Pre-merge checks | ✅ 1 | ❌ 2

❌ Failed checks (1 warning, 1 inconclusive)

Check name	Status	Explanation	Resolution
Description check	⚠️ Warning	The description 'Fix REST+SSE' is extremely vague and does not adequately explain the changes made or the purpose of the dual-mode mocking support being added.	Expand the description to clearly explain what is being fixed, what dual-mode behavior means, and how the Accept header routing improves test mocking for hybrid REST+SSE endpoints.
Title check	❓ Inconclusive	The title mentions 'hybrid controller support' but the actual changes focus on dual-mode SSE/JSON response routing with Accept header handling for test mocking utilities, which are distinct concepts.	Clarify whether 'hybrid controller' is the intended term for dual-mode behavior, or revise the title to better reflect the Accept-header-driven response routing implementation.

✅ Passed checks (1 passed)

Check name	Status	Explanation
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

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• Commit unit tests in branch feat/hybrid-support

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Actionable comments posted: 1

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Verify each finding against the current code and only fix it if needed.

Inline comments:
In `@packages/app/universal-testing-utils/README.md`:
- Around line 488-493: Update the README to clarify that MockttpHelper and
MswHelper differ: explain that mockValidResponse and mockSseResponse handlers in
MswHelper "pass through" by returning undefined (allowing other handlers), while
MockttpHelper returns HTTP 503 when the Accept header doesn't match; mention the
practical implication that mocks do not fully "coexist" under MockttpHelper
unless tests explicitly handle the 503 behavior, and suggest either documenting
the difference or instructing consumers to use the matching helper for
consistent behavior (reference MockttpHelper, MswHelper, mockValidResponse,
mockSseResponse).

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📥 Commits

Reviewing files that changed from the base of the PR and between 1a992bb and ffd12c2.

📒 Files selected for processing (6)

• packages/app/universal-testing-utils/README.md
• packages/app/universal-testing-utils/src/MockttpHelper.spec.ts
• packages/app/universal-testing-utils/src/MockttpHelper.ts
• packages/app/universal-testing-utils/src/MswHelper.spec.ts
• packages/app/universal-testing-utils/src/MswHelper.ts
• packages/app/universal-testing-utils/test/testContracts.ts