chore: adding test coverage (#2381)

* adding test coverage

* jacoco and diff

* using custom diff

* coverage with checkout

* diff cover in one workflow

---------

Co-authored-by: AR Abdul Azeez <abdul@onesignal.com>

Author: abdulraqeeb33

.github/actions/project-setup/action.yml

@@ -0,0 +1,30 @@
+runs:
+  using: composite
+  steps:
+    - name: Checkout (full history)
+      uses: actions/checkout@v4
+      with:
+        fetch-depth: 0
+
+    - name: Setup Java
+      uses: actions/setup-java@v4
+      with:
+        java-version: '17'
+        distribution: 'temurin'
+
+    - name: Setup Android SDK
+      uses: android-actions/setup-android@v3
+      with:
+        cmdline-tools-version: '10406996'
+        log-accepted-android-sdk-licenses: false
+
+    - name: Cache Gradle
+      uses: actions/cache@v4
+      with:
+        path: |
+          ~/.gradle/caches
+          ~/.gradle/wrapper
+        key: ${{ runner.os }}-gradle-${{ hashFiles('**/*.gradle*', '**/gradle-wrapper.properties', '**/gradle/libs.versions.toml') }}
+        restore-keys: |
+          ${{ runner.os }}-gradle-
+

.github/workflows/ci.yml

@@ -4,33 +4,57 @@ on:
   pull_request:
     branches: "**"
 
+env:
+  DIFF_COVERAGE_THRESHOLD: '80'
+
 jobs:
   build:
     runs-on: ubuntu-24.04
     steps:
-      - uses: actions/checkout@v4
-      - name: "[Setup] Java"
-        uses: actions/setup-java@v4
-        with:
-          java-version: '17'
-          distribution: 'temurin'
-      - name: "[Setup] Android"
-        uses: android-actions/setup-android@v3
-        with:
-          cmdline-tools-version: 10406996
-          log-accepted-android-sdk-licenses: false
-      - name: "[Test] Linting"
+      - name: "[Checkout] Repo"
+        uses: actions/checkout@v4
+      - name: "[Setup] Project"
+        uses: ./.github/actions/project-setup
+      - name: "[Code Formatting] Spotless"
         working-directory: OneSignalSDK
         run: |
           ./gradlew spotlessCheck --console=plain
-      - name: "[Test] Detekt"
+      - name: "[Static Code Analysis] Detekt"
         working-directory: OneSignalSDK
         run: |
           ./gradlew detekt --console=plain
       - name: "[Test] SDK Unit Tests"
         working-directory: OneSignalSDK
         run: |
           ./gradlew testReleaseUnitTest --console=plain --continue
+      - name: "[Coverage] Generate JaCoCo merged XML"
+        working-directory: OneSignalSDK
+        run: |
+          ./gradlew jacocoTestReportAll jacocoMergedReport --console=plain --continue
+      - name: "[Setup] Python"
+        uses: actions/setup-python@v5
+        with:
+          python-version: '3.x'
+      - name: "[Diff Coverage] Install diff-cover"
+        run: |
+          python -m pip install --upgrade pip diff-cover
+      - name: "[Diff Coverage] Check and HTML report"
+        working-directory: OneSignalSDK
+        run: |
+          REPORT=build/reports/jacoco/merged/jacocoMergedReport.xml
+          test -f "$REPORT" || { echo "Merged JaCoCo report not found at $REPORT" >&2; exit 1; }
+          python -m diff_cover.diff_cover_tool "$REPORT" \
+            --compare-branch=origin/main \
+            --fail-under=$DIFF_COVERAGE_THRESHOLD
+          python -m diff_cover.diff_cover_tool "$REPORT" \
+            --compare-branch=origin/main \
+            --html-report diff_coverage.html || true
+      - name: Upload diff coverage HTML
+        if: always()
+        uses: actions/upload-artifact@v4
+        with:
+          name: diff-coverage-report
+          path: OneSignalSDK/diff_coverage.html
       - name: Unit tests results
         if: failure()
         uses: actions/upload-artifact@v4

OneSignalSDK/build.gradle

@@ -107,3 +107,6 @@ gradle.projectsEvaluated {
         description = 'Creates/updates Detekt baselines for all modules.'
     }
 }
+
+// Apply JaCoCo configuration from separate file
+apply from: 'jacoco.gradle'