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Testing Legacy Migration Plan

Objective​

Complete the transition from the bespoke Tests harness to the Tester xUnit project by re-implementing every workflow, pipeline, and framework-package test directly in the new structure and deleting the legacy code.

Scope​

  • Move all remaining Tests/**/*.cs logic (workflows, pipelines, installers, framework packages, helpers) into Tester/.
  • Recreate shared infrastructure (WorkspaceManager, process helpers, assertions) inside Tester.Infrastructure.
  • Remove compatibility shims once no code references the legacy interfaces/types.

Phases​

Phase 1 – Shared Infrastructure Extraction​

  • Add first-class helpers in Tester.Infrastructure for:
    • ProcessRunner, ProcessRunOptions, TerminationMethod
    • CLI runner wrapper
    • WorkspaceManager, seed baseline utilities, path helpers
    • Assertion extensions needed across tests
  • Update existing xUnit tests to use the new helpers instead of Tests.Framework.*.
  • Delete the matching files from Tests/Framework after replacement.

Phase 2 – Workflow Suites Migration​

Port workflow cases one suite at a time, inlining their behavior into [Fact] methods:

  1. Init (default/named project)
  2. Build (happy path, missing app.html)
  3. Publish (success + TypeScript diagnostics)
  4. Watch
  5. Help
  6. Add (page/test generators)
  7. Test (backend test execution)
  • For each suite:
    • Copy any helper logic into Tester/Workflows/<Suite>/.
    • Remove the legacy files under Tests/Workflows/<Suite>/ once migrated.

Phase 3 – Pipeline & Installer Tests​

  • Convert CSS/HTML/JS/Core pipeline tests to native xUnit facts, referencing shared helpers and snapshot assets.
  • Move snapshots to Tester/Pipelines/.../__snapshots__.
  • Migrate package installer tests (TarballDependencyUpdate) into Tester.
  • Delete corresponding directories under Tests/Pipelines and Tests/PackageInstallers.

Phase 4 – Framework Package Suites​

  • Port PackageAutomationUnitTests, PackageAutomationIntegrationTests, and ReleaseNotesSnapshotTests into Tester/FrameworkPackages.
  • Recreate temporary repository/test workspace helpers as needed.
  • Remove the legacy files in Tests/FrameworkPackages.

Phase 5 – Final Cleanup​

  • Remove any remaining references to Tests.* in Tester.csproj.
  • Delete the Tests directory entirely.
  • Drop compatibility shims (LegacyTestCaseExecutor, LegacyTestSuiteExecutor) once unused.
  • Run dotnet test Tester/Tester.csproj (quick + full) to confirm parity.
  • Update documentation to reflect the completed migration.

Risks & Mitigations​

  • Regression risk: migrate suite-by-suite with tests green after each step.
  • Shared helper divergence: centralize utilities early (Phase 1) to avoid duplication.
  • Snapshot churn: move assets carefully and keep path references consistent.

Success Criteria​

  • No Tests/ directory or legacy abstractions remain.
  • The entire CLI/Engine coverage runs under dotnet test Tester/Tester.csproj.
  • Documentation and scripts reference only the new test project.