feat: added code coverage reporting (#9081)

* added code coverage reporting

* fix issues

* more cleanup

* fix action configs

* cleanup token debug

* added comments to codecov.yml config

---------

Co-authored-by: Edwin Jose <edwin.jose@datastax.com>

.github/workflows/ci.yml

@@ -171,12 +171,15 @@ jobs:
     secrets:
       OPENAI_API_KEY: "${{ secrets.OPENAI_API_KEY }}"
       ANTHROPIC_API_KEY: "${{ secrets.ANTHROPIC_API_KEY }}"
+      CODECOV_TOKEN: "${{ secrets.CODECOV_TOKEN }}"
 
   test-frontend-unit:
     needs: [path-filter, set-ci-condition]
     name: Run Frontend Unit Tests
     if: ${{ needs.path-filter.outputs.frontend == 'true' && needs.set-ci-condition.outputs.should-run-tests == 'true' }}
     uses: ./.github/workflows/jest_test.yml
+    secrets:
+      CODECOV_TOKEN: "${{ secrets.CODECOV_TOKEN }}"
 
   test-frontend:
     needs: [path-filter, set-ci-condition]

.github/workflows/jest_test.yml

@@ -2,6 +2,9 @@ name: Run Frontend Jest Unit Tests
 
 on:
   workflow_call:
+    secrets:
+      CODECOV_TOKEN:
+        required: false
     inputs:
       ref:
         description: "(Optional) ref to checkout"
@@ -65,6 +68,16 @@ jobs:
           junitxml-title: Unit Test Results
           junitxml-path: src/frontend/test-results/junit.xml
 
+      - name: Upload coverage to Codecov
+        uses: codecov/codecov-action@v5
+        with:
+          token: ${{ secrets.CODECOV_TOKEN }}
+          files: src/frontend/coverage/lcov.info
+          flags: frontend
+          name: frontend-coverage
+          fail_ci_if_error: false
+          directory: src/frontend/coverage/
+
       - name: Upload Coverage Reports
         uses: actions/upload-artifact@v4
         if: always()

.github/workflows/python_test.yml

@@ -7,6 +7,8 @@ on:
         required: true
       ANTHROPIC_API_KEY:
         required: true
+      CODECOV_TOKEN:
+        required: false
     inputs:
       python-versions:
         description: "(Optional) Python versions to test"
@@ -50,11 +52,13 @@ jobs:
       - uses: actions/checkout@v4
         with:
           ref: ${{ inputs.ref || github.ref }}
+
       - name: Setup Node.js
         uses: actions/setup-node@v4
         id: setup-node
         with:
           node-version: ${{ env.NODE_VERSION }}
+
       - name: "Setup Environment"
         uses: astral-sh/setup-uv@v6
         with:
@@ -62,15 +66,37 @@ jobs:
           cache-dependency-glob: "uv.lock"
           python-version: ${{ matrix.python-version }}
           prune-cache: false
+
       - name: Install the project
         run: uv sync
+
       - name: Run unit tests
         uses: nick-fields/retry@v3
         with:
           timeout_minutes: 12
           max_attempts: 2
-          command: make unit_tests args="-x -vv --splits ${{ matrix.splitCount }} --group ${{ matrix.group }} --reruns 5"
+          command: make unit_tests args="-x -vv --splits ${{ matrix.splitCount }} --group ${{ matrix.group }} --reruns 5 --cov --cov-report=xml --cov-report=html"
 
+      - name: Upload coverage to Codecov
+        uses: codecov/codecov-action@v5
+        if: matrix.python-version == '3.10'
+        with:
+          token: ${{ secrets.CODECOV_TOKEN }}
+          files: ./coverage.xml
+          flags: backend
+          name: backend-coverage-group-${{ matrix.group }}
+          fail_ci_if_error: false
+          directory: ./
+
+      - name: Upload coverage artifacts
+        uses: actions/upload-artifact@v4
+        if: matrix.python-version == '3.10'
+        with:
+          name: backend-coverage-report-group-${{ matrix.group }}
+          path: |
+            coverage.xml
+            htmlcov/
+          retention-days: 30
 
 
   integration-tests:

codecov.yml

@@ -0,0 +1,85 @@
+codecov:
+  # Don't block CI if codecov fails to process reports
+  require_ci_to_pass: false
+  notify:
+    after_n_builds: 1  # Comment after each report (don't wait for all)
+
+coverage:
+  precision: 2
+  round: down
+  # Display range from 30-100% to provide meaningful color gradients
+  range: "30...100"
+
+  status:
+    project:
+      # Overall project coverage target
+      default:
+        target: 60%
+        threshold: 3%
+
+      # Backend coverage strategy: Aspirational target for progress tracking
+      # Current coverage: ~33%, Target: 55% (intentionally higher than current)
+      # This creates visual progress indicators (red->yellow->green) without blocking PRs
+      # Shows improvement over time while encouraging better test coverage
+      backend:
+        target: 55%
+        # Threshold: Allowable drop in coverage before failing the check
+        # 5% = coverage can drop from 33% to 28% without failing status
+        # Higher threshold to avoid blocking PRs during improvement phase
+        threshold: 5%
+        flags:
+          - backend
+
+      # Frontend coverage: Realistic target based on current state
+      # Current coverage: ~70%, maintains existing high standards
+      frontend:
+        target: 70%
+        # Threshold: Allowable drop in coverage before failing the check
+        # 2% = coverage can drop from 70% to 68% without failing status
+        # Stricter threshold to maintain established quality standards
+        threshold: 2%
+        flags:
+          - frontend
+
+    # New code coverage requirements - encourages well-tested new features
+    patch:
+      default:
+        target: 70%
+        threshold: 3%
+
+# PR comment configuration - what information to show in coverage reports
+comment:
+  layout: "reach,diff,flags,tree"  # Show coverage, changes, flags, and file tree
+  behavior: default
+  require_changes: false  # Comment even if no changes
+  require_base: false     # Don't require base branch comparison
+  require_head: true      # Require current branch coverage
+
+# Define separate coverage tracking for frontend and backend
+flags:
+  backend:
+    paths:
+      - src/backend/
+    carryforward: true  # Preserve coverage data across builds if missing
+  frontend:
+    paths:
+      - src/frontend/
+    carryforward: true  # Preserve coverage data across builds if missing
+
+# Files/directories to exclude from coverage calculations
+ignore:
+  # Database migrations - infrastructure code, not business logic
+  - "src/backend/base/langflow/alembic/**"
+  # Test files themselves don't need coverage
+  - "src/backend/tests/**"
+  - "src/frontend/tests/**"
+  - "src/frontend/test-results/**"
+  # Build artifacts and dependencies
+  - "**/__pycache__/**"
+  - "**/*.pyc"
+  - "**/node_modules/**"
+  - "**/coverage/**"
+  # Python package init files - typically just imports
+  - "**/__init__.py"
+  # Database migrations
+  - "**/migrations/**"