ci: add unit test workflow

[torlando-tech]

Summary

• Adds GitHub Actions workflow that runs ColumbaAppTests (17 tests) on PRs and pushes to main
• Clones sibling local packages (reticulum-swift, LXMF-swift, LXST-swift) for the build
• Runs on macOS 15 with Xcode 16.2, targeting iPhone 16 simulator

Test plan

• Verify the workflow runs successfully on this PR
• All 17 tests pass locally

🤖 Generated with Claude Code

[greptile-apps]

Greptile Summary

This PR adds a GitHub Actions CI workflow that builds ColumbaApp and runs its 17-test suite on every PR and push to main. The overall structure is solid — correct triggers, concurrency cancellation, explicit Xcode version selection, and a dedicated dependency-resolution step before testing.\n\nThree minor improvements worth considering before this workflow is relied upon heavily:\n\n- Sibling packages are cloned at HEAD (reticulum-swift, LXMF-swift, LXST-swift) without pinning to a branch, tag, or SHA. A breaking change in any of those repos will fail this workflow even if columba-ios itself hasn't changed, making it harder to attribute failures correctly.\n- The .xcresult bundle is never uploaded. -resultBundlePath TestResults.xcresult is specified but there is no actions/upload-artifact step, so failure diagnostics are lost when the runner is recycled.\n- No SPM caching. With several heavyweight dependencies (MapLibre, GRDB, CryptoSwift), adding an actions/cache step keyed on Package.resolved would meaningfully shorten run times.

Confidence Score: 5/5

Safe to merge — the workflow is functionally correct and all findings are non-blocking P2 suggestions.

No P0 or P1 issues were found. The three observations (unpinned sibling clones, missing artifact upload, no SPM cache) are quality-of-life improvements that do not affect correctness or security.

No files require special attention.

Important Files Changed

Filename	Overview
.github/workflows/tests.yml	Adds a GitHub Actions workflow that runs 17 unit tests on PRs and pushes to main using macOS-15 / Xcode 16.2; sibling local packages are cloned at HEAD, the result bundle is never uploaded, and SPM deps are not cached.

Sequence Diagram

sequenceDiagram
    participant GH as GitHub Actions
    participant Runner as macOS-15 Runner
    participant Sibling as Sibling Repos (GitHub)
    participant SPM as Swift Package Registry
    participant Sim as iPhone 16 Simulator

    GH->>Runner: Trigger (PR / push to main)
    Runner->>Runner: actions/checkout@v4
    Runner->>Sibling: git clone reticulum-swift (HEAD)
    Runner->>Sibling: git clone LXMF-swift (HEAD)
    Runner->>Sibling: git clone LXST-swift (HEAD)
    Runner->>Runner: xcode-select Xcode 16.2
    Runner->>SPM: xcodebuild -resolvePackageDependencies
    SPM-->>Runner: Fetch pinned packages (GRDB, CryptoSwift, MapLibre…)
    Runner->>Sim: xcodebuild test -only-testing:ColumbaAppTests
    Sim-->>Runner: Test results → TestResults.xcresult
    Runner->>Runner: Job ends, .xcresult discarded

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_{Reviews (1): Last reviewed commit: "ci: add GitHub Actions workflow to run u..." | Re-trigger Greptile}

[greptile-apps]

Sibling packages cloned at HEAD without pinning

The three sibling repos are cloned without specifying a branch, tag, or commit SHA, so every CI run always uses the latest HEAD of each package's default branch. If someone pushes a breaking change to reticulum-swift, LXMF-swift, or LXST-swift, this workflow will start failing even though nothing in columba-ios changed, making it hard to tell whether the failure is local or upstream.

Consider pinning to a specific branch or ref so the build is reproducible and failures are attributable:

git clone --branch main --single-branch https://github.com/torlando-tech/reticulum-swift.git ../reticulum-swift
git clone --branch main --single-branch https://github.com/torlando-tech/LXMF-swift.git ../LXMF-swift
git clone --branch main --single-branch https://github.com/torlando-tech/LXST-swift.git ../LXST-swift

Or, if full reproducibility is needed, add a step that resolves and records the HEAD SHAs of each sibling so failed runs can be replicated exactly.

[greptile-apps]

Test result bundle generated but never uploaded

-resultBundlePath TestResults.xcresult writes the result bundle to disk, but there is no actions/upload-artifact step afterward. When a test run fails in CI, the .xcresult bundle is discarded along with the runner and there is no way to inspect the failure from the GitHub Actions UI.

Consider adding an upload step so the bundle is available for debugging:

      - name: Upload test results
        if: always()
        uses: actions/upload-artifact@v4
        with:
          name: TestResults
          path: TestResults.xcresult

Using if: always() ensures the artifact is uploaded even when tests fail, which is when it's most useful.

[greptile-apps]

SPM dependency cache not configured

Every run fetches all remote Swift Package dependencies from scratch (GRDB, CryptoSwift, MapLibre, etc.). Caching the resolved packages significantly reduces run time. A common pattern:

      - name: Cache Swift packages
        uses: actions/cache@v4
        with:
          path: |
            ~/Library/Developer/Xcode/DerivedData
            .build
          key: ${{ runner.os }}-spm-${{ hashFiles('**/Package.resolved') }}
          restore-keys: |
            ${{ runner.os }}-spm-

The Package.resolved hash ensures the cache is invalidated whenever a dependency version changes.