Test HTTP command error responses through real endpoints #605

Problem

The HTTP result-mapping code has approximately 24% line coverage in the October 5, 2026 .NET 10 coverage run. Most error-response paths are untested. These paths define the status codes and problem-details bodies that API clients rely on. You can view a test coverage report I generated here: index.html

Source: ResultExtensions.cs.

Proposed tests

Send HTTP requests to test endpoints backed by command services that produce each outcome:

Cover both minimal-API and controller command mappings, since they use separate result-conversion paths. Assert the response content type and stable problem-details fields, including domain errors where applicable.

Acceptance criteria

• Each outcome is exercised through an HTTP request to a hosted test application.
• Both minimal-API and controller mappings are covered.
• Assertions verify status codes and response bodies, rather than only whether requests complete.
• Error responses use the expected problem-details content type and structure.
• Tests avoid brittle comparisons of full exception stack traces.
• No direct tests of ResultExtensions, external database, or Docker container are required.

Validation

Extend the existing ASP.NET Core test application and run the affected endpoint tests. Collect focused coverage for the HTTP result-mapping paths; do not rerun unrelated provider suites.