Add code coverage using codecov.io

.github/.codecov.yaml

@@ -0,0 +1,28 @@
+codecov:
+  require_ci_to_pass: yes
+  max_report_age: off
+
+coverage:
+  precision: 2
+  round: down
+  range: "80...100"
+
+parsers:
+  gcov:
+    branch_detection:
+      conditional: yes
+      loop: yes
+      method: no
+      macro: no
+
+comment:
+  layout: "reach,diff,flags,tree"
+  behavior: default
+  require_changes: no
+
+# Relative file path fixing.
+# CI file paths must match Git file paths.
+# This fix removes the "/home/runner/" prefix 
+# to coverage report file paths.
+fixes:
+  - "/home/runner/::"

.github/workflows/ci.yml

@@ -182,3 +182,19 @@ jobs:
         ./ci/setup_windows_ci_environment.ps1
     - name: run tests
       run: ./ci/do_ci.ps1 cmake.test_example_plugin
+
+  code_coverage:
+    name: Code coverage
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - name: setup
+      run: |
+        sudo ./ci/setup_cmake.sh
+        sudo ./ci/setup_ci_environment.sh
+    - name: run tests and generate report
+      run: ./ci/do_ci.sh code.coverage
+    - name: upload report
+      uses: codecov/codecov-action@v1
+      with:
+        file: /home/runner/build/coverage.info

ci/README.md

@@ -13,6 +13,7 @@ CI tests can be run on docker by invoking the script `./ci/run_docker.sh ./ci/do
 * `bazel.tsan`: build bazel targets and run tests with ThreadSanitizer.
 * `benchmark`: run all benchmarks.
 * `format`: use `tools/format.sh` to enforce text formatting.
+* `code.coverage`: build cmake targets and run tests. Then upload coverage report to [codecov.io](https://codecov.io/).
 
 Additionally, `./ci/run_docker.sh` can be invoked with no arguments to get a docker shell where tests
 can be run manually.

ci/do_ci.sh

@@ -116,6 +116,16 @@ elif [[ "$1" == "format" ]]; then
     exit 1
   fi
   exit 0
+elif [[ "$1" == "code.coverage" ]]; then
+  cd "${BUILD_DIR}"
+  rm -rf *
+  cmake -DCMAKE_BUILD_TYPE=Debug  \
+        -DCMAKE_CXX_FLAGS="-Werror --coverage" \
+        "${SRC_DIR}"
+  make
+  make test
+  lcov --directory $PWD --capture --output-file coverage.info
+  exit 0
 fi
 
 echo "Invalid do_ci.sh target, see ci/README.md for valid targets."

ci/setup_ci_environment.sh

@@ -7,3 +7,4 @@ apt-get install --no-install-recommends --no-install-suggests -y \
                 ca-certificates \
                 wget \
                 git
+apt-get install -y lcov