Added UnitTest cases for adapter.

adapter/src/test/java/com/iluwatar/adapter/AdapterPatternTest.java

@@ -0,0 +1,68 @@
+package com.iluwatar.adapter;
+
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.verify;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import org.junit.Before;
+import org.junit.Test;
+
+/**
+ * An adapter helps two incompatible interfaces to work together. This is the real world definition
+ * for an adapter. Interfaces may be incompatible but the inner functionality should suit the need.
+ * The Adapter design pattern allows otherwise incompatible classes to work together by converting
+ * the interface of one class into an interface expected by the clients.
+ * 
+ * <p>There are two variations of the Adapter pattern: 
+ * The class adapter implements the adaptee's
+ * interface whereas the object adapter uses composition to contain the adaptee in the adapter
+ * object. This example uses the object adapter approach.
+ * 
+ * <p>The Adapter ({@link GnomeEngineer}) converts the interface 
+ * of the target class ({@link GoblinGlider}) into a suitable one expected by 
+ * the client ({@link GnomeEngineeringManager}
+ * ).
+ */
+public class AdapterPatternTest {
+
+  private Map<String, Object> beans;
+
+  private static final String ENGINEER_BEAN = "engineer";
+
+  private static final String MANAGER_BEAN = "manager";
+
+  /**
+   * This method runs before the test execution and sets the bean objects in the beans Map.
+   */
+  @Before
+  public void setup() {
+    beans = new HashMap<>();
+
+    GnomeEngineer gnomeEngineer = spy(new GnomeEngineer());
+    beans.put(ENGINEER_BEAN, gnomeEngineer);
+
+    GnomeEngineeringManager manager = new GnomeEngineeringManager();
+    manager.setEngineer((GnomeEngineer) beans.get(ENGINEER_BEAN));
+    beans.put(MANAGER_BEAN, manager);
+  }
+
+  /**
+   * This test asserts that when we call operateDevice() method on a manager bean, it is internally
+   * calling operateDevice method on the engineer object. The Adapter ({@link GnomeEngineer})
+   * converts the interface of the target class ( {@link GoblinGlider}) into a suitable one expected
+   * by the client ({@link GnomeEngineeringManager} ).
+   */
+  @Test
+  public void testAdapter() {
+    Engineer manager = (Engineer) beans.get(MANAGER_BEAN);
+
+    // when manager is asked to operate device
+    manager.operateDevice();
+
+    // Manager internally calls the engineer object to operateDevice
+    Engineer engineer = (Engineer) beans.get(ENGINEER_BEAN);
+    verify(engineer).operateDevice();
+  }
+}

adapter/src/test/java/com/iluwatar/adapter/AppTest.java

@@ -1,19 +0,0 @@
-package com.iluwatar.adapter;
-
-import org.junit.Test;
-
-import com.iluwatar.adapter.App;
-
-/**
- * 
- * Application test
- *
- */
-public class AppTest {
-
-  @Test
-  public void test() {
-    String[] args = {};
-    App.main(args);
-  }
-}