[Sprint 11] Migrate Web.Tests.Integration to xUnit v3

[mpaulosky]

Goal

Migrate tests/Web.Tests.Integration from xUnit v2 to xUnit v3 using the same package and runner pattern already proven in prior test-project migrations.

Spike Summary

• Spike issue: [Sprint 11] spike: validate Web.Tests.Integration for xUnit v3 migration #195
• Active tests: 12
• Real test files: 3
• Non-test/template file: IntegrationTest1.cs contains a commented example [Fact]
• Current fixtures: MongoDB + Redis Testcontainers via xUnit collection fixtures
• Current runner config already exists in xunit.runner.json
• Current suite passes in Release configuration

Scope

• Replace xunit with xunit.v3 in Web.Tests.Integration.csproj
• Keep xunit.runner.visualstudio
• Preserve Testcontainers-based collection/fixture behavior
• Review xunit.runner.json and keep integration-safe parallel settings unless evidence supports a change
• Update file headers so project naming is consistent with Web.Tests.Integration
• Remove or resolve stale template content if it no longer belongs in the suite
• Keep the suite green in Release configuration

Acceptance Criteria

• Web.Tests.Integration.csproj uses xunit.v3
• xunit.runner.json is correct for this integration suite
• File headers consistently identify Web.Tests.Integration
• Any stale starter/template test file is removed or intentionally retained with clear purpose
• All Web.Tests.Integration tests pass in Release configuration
• No regression in the MongoDB/Redis fixture-based tests

Sprint

Sprint 11 - xUnit v3 (Web.Tests.Integration)

Plan Reference

Todo ID: sprint-11-migration

Routing

Assigned to Gimli (squad:gimli) because this is test-project migration work with integration-test fixtures.

[github-actions]

📋 Assigned to Gimli (Tester)

Issue: #199 — [Sprint 11] Migrate Web.Tests.Integration to xUnit v3

Gimli will pick this up in the next Copilot session.

For Copilot coding agent: If enabled, this issue will be worked automatically.
Otherwise, start a Copilot session and say:
Gimli, work on issue #199

[mpaulosky]

Ralph handoff

This issue was created from spike #195.

Implement from these confirmed findings

• 12 active tests across 3 real test files
• Existing MongoDB + Redis Testcontainers fixtures are already working
• Existing xunit.runner.json should be treated as integration-specific, not blindly normalized to the unit-test default
• IntegrationTest1.cs is stale starter content and should be evaluated during the migration

Delivery target

Open a PR that closes #199 so the board automation moves the issue through In review and Done correctly.