Add proper tests for flyweight pattern

flyweight/src/main/java/com/iluwatar/flyweight/AlchemistShop.java

@@ -1,6 +1,7 @@
 package com.iluwatar.flyweight;
 
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.List;
 
 /**
@@ -39,6 +40,24 @@ public class AlchemistShop {
     bottomShelf.add(factory.createPotion(PotionType.HOLY_WATER));
   }
 
+  /**
+   * Get a read-only list of all the items on the top shelf
+   *
+   * @return The top shelf potions
+   */
+  public final List<Potion> getTopShelf() {
+    return Collections.unmodifiableList(this.topShelf);
+  }
+
+  /**
+   * Get a read-only list of all the items on the bottom shelf
+   *
+   * @return The bottom shelf potions
+   */
+  public final List<Potion> getBottomShelf() {
+    return Collections.unmodifiableList(this.bottomShelf);
+  }
+
   public void enumerate() {
 
     System.out.println("Enumerating top shelf potions\n");

flyweight/src/test/java/com/iluwatar/flyweight/AlchemistShopTest.java

@@ -0,0 +1,40 @@
+package com.iluwatar.flyweight;
+
+import org.junit.Test;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+
+/**
+ * Date: 12/12/15 - 10:54 PM
+ *
+ * @author Jeroen Meulemeester
+ */
+public class AlchemistShopTest {
+
+  @Test
+  public void testShop() throws Exception {
+    final AlchemistShop shop = new AlchemistShop();
+
+    final List<Potion> bottomShelf = shop.getBottomShelf();
+    assertNotNull(bottomShelf);
+    assertEquals(5, bottomShelf.size());
+
+    final List<Potion> topShelf = shop.getTopShelf();
+    assertNotNull(topShelf);
+    assertEquals(8, topShelf.size());
+
+    final List<Potion> allPotions = new ArrayList<>();
+    allPotions.addAll(topShelf);
+    allPotions.addAll(bottomShelf);
+
+    // There are 13 potion instances, but only 5 unique instance types
+    assertEquals(13, allPotions.size());
+    assertEquals(5, allPotions.stream().map(System::identityHashCode).distinct().count());
+
+  }
+
+}