Add coverage test

.github/workflows/coverage.yml

@@ -0,0 +1,26 @@
+name: Measure coverage
+
+on:
+  push:
+    branches: [ master ]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: Set up JDK 11
+        uses: actions/setup-java@v1
+        with:
+          java-version: 11
+      - name: Run Coverage
+        run: |
+          chmod +x gradlew
+          ./gradlew build jacocoTestCoverage
+
+      - name: Add coverage to PR
+        id: jacoco
+        uses: madrapps/jacoco-report@v1.2
+        with:
+          paths: /build/reports/jacoco/test/jacocoTestReport.xml
+          token: ${{ secrets.GITHUB_TOKEN }}