Add automated testing harness (closes #10)

[OliverRC]

Task

Closes #10 — a full automated testing harness so kickflip's behaviour is no longer hand-tested.

What was done

Added unit and integration tests covering the tool's behaviour:

• Different modes — Tags, GitHubMergePR and Folder are all exercised, at both the service level (GitServiceTests, FileSystemServiceTests) and end-to-end through the CLI (CliIntegrationTests).
• Dry run makes no changes — SftpDeploymentServiceTests verify a dry run does not connect and does not touch local files; CliIntegrationTests verify the CLI reports planned changes and never connects during a dry run.
• Different commands — deploy and github pull-request command wiring, help output and argument validation are covered.

Key decisions

• Git-based tests build real temporary git repositories (GitRepositoryBuilder) rather than mocking LibGit2Sharp, so find modes are proven end-to-end.
• Integration tests drive the compiled CLI as an external process (CliRunner), covering argument parsing and handler wiring.
• Live SFTP/FTP servers cannot be stood up in unit tests, so remote-deployment coverage focuses on the safety-critical dry-run path.

Files changed

• src/kickflip.Tests/TestHelpers/{TempDirectory,GitRepositoryBuilder,CliRunner}.cs
• src/kickflip.Tests/{Utilities,IgnoreService,FileSystemService,GitService,OutputService,SftpDeploymentService,CliIntegration}Tests.cs
• README.md (Testing section)

46 tests pass via dotnet test.

Blockers for next iteration

• The CI token lacks workflow scope, so I could not add a dotnet test step to .github/workflows/main.yml. A maintainer should add that step.
• Live SFTP/FTP end-to-end testing would need a containerised server; deferred.

[OliverRC]

Review refinements applied:

• Consolidated repeated CLI integration assertions into small helper methods for clarity and reduced duplication.
• Centralised dummy SFTP/CLI credential constants in a shared helper (single source of truth).
• Improved readability by extracting assembly path resolution and using null-checking.
• Made unit tests a bit more explicit by naming services (, ) and avoiding repeated nesting.
• Added and helpers to make ignore-related tests more intention-revealing.
• Minor consistency tweaks ( instead of , clearer local variable names).

All tests still pass ( Determining projects to restore...
All projects are up-to-date for restore.
kickflip -> /home/agent/workspace/src/kickflip/bin/Debug/net8.0/kickflip.dll
kickflip.Tests -> /home/agent/workspace/src/kickflip.Tests/bin/Debug/net8.0/kickflip.Tests.dll
Test run for /home/agent/workspace/src/kickflip.Tests/bin/Debug/net8.0/kickflip.Tests.dll (.NETCoreApp,Version=v8.0)
VSTest version 17.11.1 (arm64)

Starting test execution, please wait...
A total of 1 test files matched the specified pattern.

Passed! - Failed: 0, Passed: 46, Skipped: 0, Total: 46, Duration: 325 ms - kickflip.Tests.dll (net8.0)).

[OliverRC]

Follow-up: I noticed package-lock.json was untracked in the working tree; I committed it to keep the branch consistent.