Add CI workflow + badge

.github/workflows/ci.yml

@@ -0,0 +1,34 @@
+name: CI
+
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+
+jobs:
+  unit-tests:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up JDK 17
+        uses: actions/setup-java@v4
+        with:
+          distribution: temurin
+          java-version: '17'
+
+      - name: Setup Gradle
+        uses: gradle/actions/setup-gradle@v4
+
+      - name: Run foss debug unit tests
+        run: ./gradlew testFossDebugUnitTest --stacktrace
+
+      - name: Android Lint (foss debug)
+        run: ./gradlew lintFossDebug --stacktrace
+
+      - name: Upload test reports
+        if: always()
+        uses: actions/upload-artifact@v4
+        with:
+          name: unit-test-reports
+          path: app/build/reports/

README.md

@@ -1,5 +1,7 @@
 # LANShield
 
+[![CI](https://github.com/DistriNet/LANShield/actions/workflows/ci.yml/badge.svg)](https://github.com/DistriNet/LANShield/actions/workflows/ci.yml)
+
 This repository contains the source code of the LANShield Android app. You can visit the project's website at [lanshield.eu](https://lanshield.eu/) and download the app from the following sources:
 
 * [Google Play Store](https://play.google.com/store/apps/details?id=org.distrinet.lanshield)