Add test for MapperModule

scm-webapp/src/test/java/sonia/scm/api/v2/resources/MapperModuleTest.java

@@ -0,0 +1,33 @@
+package sonia.scm.api.v2.resources;
+
+import com.google.inject.binder.AnnotatedBindingBuilder;
+import org.junit.Test;
+import org.mockito.ArgumentCaptor;
+
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+public class MapperModuleTest {
+
+  @Test
+  public void shouldBindToClassesWithDefaultConstructorOnly() {
+    AnnotatedBindingBuilder binding = mock(AnnotatedBindingBuilder.class);
+    ArgumentCaptor<Class> captor = ArgumentCaptor.forClass(Class.class);
+    when(binding.to(captor.capture())).thenReturn(null);
+    new MapperModule() {
+      @Override
+      protected <T> AnnotatedBindingBuilder<T> bind(Class<T> clazz) {
+        return binding;
+      }
+    }.configure();
+    captor.getAllValues().forEach(this::verifyClassCanBeInstantiated);
+  }
+
+  private <T> T verifyClassCanBeInstantiated(Class<T> c) {
+    try {
+      return c.getConstructor().newInstance();
+    } catch (Exception e) {
+      throw new RuntimeException(e);
+    }
+  }
+}