Add GitHub build action

.github/workflows/build.yml

@@ -0,0 +1,25 @@
+name: r2-shared-kotlin
+
+on:
+  push:
+    branches: [ develop ]
+  pull_request:
+    branches: [ develop ]
+
+jobs:
+  build:
+    name: Build and test
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+      - name: Set up JDK 11
+        uses: actions/setup-java@v2
+        with:
+          java-version: '11'
+          distribution: 'adopt'
+      - name: Build
+        run: ./gradlew build -x test
+      - name: Test
+        run: ./gradlew test

r2-shared/src/test/java/org/readium/r2/shared/TestUtils.kt

@@ -18,6 +18,7 @@ import org.readium.r2.shared.extensions.toMap
 import org.readium.r2.shared.fetcher.Fetcher
 import org.readium.r2.shared.fetcher.Resource
 import org.readium.r2.shared.publication.Link
+import org.readium.r2.shared.util.use
 import java.io.File
 import java.net.URL