test: set up coverage infrastructure in CI

- Add pytest-cov to dev dependencies
- Add .coveragerc with branch coverage, 60% floor (current baseline),
  and source/omit configuration
- Add coverage CI job (ubuntu/py3.13) that runs pytest with --cov,
  enforces the floor, and uploads coverage.xml as an artifact
- Wire coverage into the required-checks-passed gate

Closes #2080

Author: KRRT7

.coveragerc

@@ -0,0 +1,17 @@
+[run]
+branch = true
+source = codeflash
+omit =
+    codeflash/version.py
+
+[report]
+sort = cover
+show_missing = true
+fail_under = 60
+exclude_lines =
+    pragma: no cover
+    if TYPE_CHECKING:
+    if __name__ == .__main__.:
+
+[html]
+directory = htmlcov

.github/workflows/ci.yaml

@@ -151,6 +151,44 @@ jobs:
       - name: Unit tests
         run: uv run pytest tests/
 
+  # ---------------------------------------------------------------------------
+  # Coverage — single run on ubuntu/py3.13 to enforce the coverage floor.
+  # ---------------------------------------------------------------------------
+  coverage:
+    needs: determine-changes
+    if: needs.determine-changes.outputs.unit_tests == 'true'
+    runs-on: ubuntu-latest
+    env:
+      PYTHONIOENCODING: utf-8
+    steps:
+      - uses: actions/checkout@v6
+        with:
+          fetch-depth: 1
+          token: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Install uv
+        uses: astral-sh/setup-uv@v8.0.0
+        with:
+          python-version: "3.13"
+          enable-cache: true
+
+      - name: Install dependencies
+        run: uv sync
+
+      - name: Run tests with coverage
+        run: uv run pytest tests/ --cov=codeflash --cov-report=xml:coverage.xml --cov-report=term-missing --cov-config=.coveragerc
+
+      - name: Check coverage floor
+        run: uv run coverage report --fail-under=60
+
+      - name: Upload coverage report
+        if: always()
+        uses: actions/upload-artifact@v4
+        with:
+          name: coverage-report
+          path: coverage.xml
+          retention-days: 30
+
   # ---------------------------------------------------------------------------
   # Mypy type checking
   # ---------------------------------------------------------------------------
@@ -507,6 +545,7 @@ jobs:
     if: always()
     needs:
       - unit-tests
+      - coverage
       - type-check
       - prek
       - e2e-python

pyproject.toml

@@ -89,6 +89,7 @@ dev = [
     "prek>=0.2.25",
     "ty>=0.0.14",
     "uv>=0.9.29",
+    "pytest-cov>=7.1.0",
 ]
 tests = [
     "black>=25.9.0",