CI: Add back coverage check (#18600)

Author: masci

.github/workflows/coverage.yml

@@ -6,6 +6,14 @@ on:
       - main
   pull_request:
 
+env:
+  # How many concurrent processes running pytest in a single CI job
+  NUM_WORKERS: 8
+  # Tests will fail if coverage percentage is below this number
+  COV_FAIL_UNDER: 50
+  # Which Python from the matrix will be used to run the coverage check
+  COV_PYTHON_VERSION: 3.12
+
 jobs:
   test:
     runs-on: ubuntu-latest-unit-tester
@@ -25,10 +33,20 @@ jobs:
           enable-cache: true
 
       - name: Run tests
-        id: packages-to-test
+        if: ${{ matrix.python-version != env.COV_PYTHON_VERSION }}
+        shell: bash
+        run: |
+          git fetch origin ${{ github.event.pull_request.base.ref }}:${{ github.event.pull_request.base.ref }}
+          uv run -- python -u scripts/run_ci_tests.py \
+            --workers ${{ env.NUM_WORKERS }} \
+            --base-ref=${{ github.event.pull_request.base.ref }}
+
+      - name: Run tests with coverage
+        if: ${{ matrix.python-version == env.COV_PYTHON_VERSION }}
         shell: bash
-        env:
-          NUM_WORKERS: 8
         run: |
           git fetch origin ${{ github.event.pull_request.base.ref }}:${{ github.event.pull_request.base.ref }}
-          uv run -- python -u scripts/run_ci_tests.py --workers ${{ env.NUM_WORKERS }} --base-ref=${{ github.event.pull_request.base.ref }}
+          uv run -- python -u scripts/run_ci_tests.py \
+            --workers ${{ env.NUM_WORKERS }} \
+            --base-ref=${{ github.event.pull_request.base.ref }} \
+            --cov-fail-under=${{ env.COV_FAIL_UNDER }}

.github/workflows/unit_test.yml

@@ -8,6 +8,7 @@ dev = [
     "boto3==1.33.6",
     "botocore>=1.33.13",
     "codespell[toml]>=v2.2.6",
+    "diff-cover>=9.2.0",
     "llama-cloud>=0.0.6",
     "mypy==1.11.0",
     "openai",

llama-index-core/pyproject.toml

@@ -6,15 +6,16 @@ build-backend = "hatchling.build"
 dev = [
     "black[jupyter]<=23.9.1,>=23.7.0",
     "codespell[toml]>=v2.2.6",
+    "diff-cover>=9.2.0",
     "ipython==8.10.0",
     "jupyter>=1.0.0,<2",
     "mypy==0.991",
     "pre-commit==3.2.0",
     "pylint==2.15.10",
     "pytest==7.2.1",
+    "pytest-cov>=6.1.1",
     "pytest-mock==3.11.1",
     "ruff==0.0.292",
-    "tree-sitter-languages>=1.8.0,<2",
     "types-Deprecated>=0.1.0",
     "types-PyYAML>=6.0.12.12,<7",
     "types-protobuf>=4.24.0.4,<5",