Added tests for multiton pattern

multiton/src/test/java/com/iluwatar/multiton/NazgulTest.java

@@ -0,0 +1,29 @@
+package com.iluwatar.multiton;
+
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertSame;
+
+/**
+ * Date: 12/22/15 - 22:28 AM
+ *
+ * @author Jeroen Meulemeester
+ */
+public class NazgulTest {
+
+  /**
+   * Verify if {@link Nazgul#getInstance(NazgulName)} returns the correct Nazgul multiton instance
+   */
+  @Test
+  public void testGetInstance() {
+    for (final NazgulName name : NazgulName.values()) {
+      final Nazgul nazgul = Nazgul.getInstance(name);
+      assertNotNull(nazgul);
+      assertSame(nazgul, Nazgul.getInstance(name));
+      assertEquals(name, nazgul.getName());
+    }
+  }
+
+}