test: add automated testing framework with Vitest

Add comprehensive testing infrastructure:

**Testing Framework:**
- Add Vitest as test runner (fast, TypeScript-friendly, ESM support)
- Add @vitest/coverage-v8 for code coverage reports
- Add @vitest/ui for interactive test UI
- Configure vitest.config.ts with proper paths and coverage settings

**Unit Tests:**
- Add tests/unit/linear-service-cycles.test.ts (14 tests)
- Test getCycles(), getCycleById(), resolveCycleId() methods
- Use mocks to avoid API calls
- Verify PR czottmann#4 cycle methods work correctly

**Integration Tests:**
- Add tests/integration/cycles-cli.test.ts (8 tests)
- Add tests/integration/project-milestones-cli.test.ts (5 tests)
- Test end-to-end CLI functionality
- Verify no "query too complex" errors (main bug fix)
- Test all command flags and JSON output structure
- Auto-skip if LINEAR_API_TOKEN not set

**Command Coverage Tool:**
- Add tests/command-coverage.ts for CLI-specific coverage analysis
- Shows which commands have integration tests (more relevant than code coverage)
- Automatically discovers new commands and tests
- Reports: 35% of commands tested (cycles and project-milestones fully covered)

**CI/CD:**
- Add .github/workflows/ci.yml for automated testing
- Run tests on every push and PR
- Separate jobs for testing and linting
- Optional integration tests if LINEAR_API_TOKEN secret configured

**Scripts:**
- pnpm test - Run all tests
- pnpm test:watch - Run tests in watch mode
- pnpm test:ui - Run tests with UI
- pnpm test:coverage - Generate code coverage report
- pnpm test:commands - Show command coverage report

**Test Results:**
- All 27 tests passing
- Unit tests: 14 passed (instant, no API)
- Integration tests: 13 passed (~15 seconds with API)
- Command coverage: 35% (7/20 commands tested)
- Cycles and project-milestones commands fully covered

This establishes automated testing practices for the linearis project
and prevents regressions in PR czottmann#4 fixes.

Author: ryanrozich

.github/workflows/ci.yml

@@ -0,0 +1,74 @@
+name: CI
+
+on:
+  push:
+    branches: [main, pr-*]
+  pull_request:
+    branches: [main]
+
+jobs:
+  test:
+    name: Test on Node ${{ matrix.node-version }}
+    runs-on: ubuntu-latest
+
+    strategy:
+      matrix:
+        node-version: [22.x]
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Install pnpm
+        uses: pnpm/action-setup@v4
+        with:
+          version: 10.14.0
+
+      - name: Setup Node.js ${{ matrix.node-version }}
+        uses: actions/setup-node@v4
+        with:
+          node-version: ${{ matrix.node-version }}
+          cache: 'pnpm'
+
+      - name: Install dependencies
+        run: pnpm install --frozen-lockfile
+
+      - name: Build project
+        run: pnpm run build
+
+      - name: Run unit tests
+        run: pnpm test
+
+      - name: Run integration tests (if API token available)
+        if: env.LINEAR_API_TOKEN != ''
+        env:
+          LINEAR_API_TOKEN: ${{ secrets.LINEAR_API_TOKEN }}
+        run: pnpm test
+
+  lint:
+    name: Lint and Type Check
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Install pnpm
+        uses: pnpm/action-setup@v4
+        with:
+          version: 10.14.0
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: 22.x
+          cache: 'pnpm'
+
+      - name: Install dependencies
+        run: pnpm install --frozen-lockfile
+
+      - name: TypeScript type check
+        run: pnpm run build
+
+      - name: Check for TypeScript errors
+        run: pnpm exec tsc --noEmit

package.json

@@ -14,7 +14,11 @@
     "build": "tsc && chmod +x dist/main.js",
     "clean": "rm -rf dist/",
     "start": "tsx src/main.ts",
-    "test": "echo \"Error: no test specified\" && exit 1"
+    "test": "vitest run",
+    "test:watch": "vitest",
+    "test:ui": "vitest --ui",
+    "test:coverage": "vitest run --coverage",
+    "test:commands": "tsx tests/command-coverage.ts"
   },
   "engines": {
     "node": ">=22.0.0"
@@ -28,14 +32,17 @@
   ],
   "author": "Carlo Zottmann <[email protected]>",
   "license": "MIT",
-  "packageManager": "pnpm@10.14.0",
+  "packageManager": "pnpm@10.20.0",
   "dependencies": {
     "@linear/sdk": "^58.1.0",
     "commander": "^14.0.0"
   },
   "devDependencies": {
     "@types/node": "^22.0.0",
+    "@vitest/coverage-v8": "^2.1.8",
+    "@vitest/ui": "^2.1.8",
     "tsx": "^4.20.5",
-    "typescript": "^5.0.0"
+    "typescript": "^5.0.0",
+    "vitest": "^2.1.8"
   }
 }