Added tests for private-class-data pattern

private-class-data/src/test/java/com/iluwatar/privateclassdata/StewTest.java

@@ -0,0 +1,33 @@
+package com.iluwatar.privateclassdata;
+
+import org.junit.Test;
+import org.mockito.InOrder;
+
+import static org.mockito.Mockito.inOrder;
+
+/**
+ * Date: 12/27/15 - 10:46 PM
+ *
+ * @author Jeroen Meulemeester
+ */
+public class StewTest extends StdOutTest {
+
+  /**
+   * Verify if mixing the stew doesn't change the internal state
+   */
+  @Test
+  public void testMix() {
+    final ImmutableStew stew = new ImmutableStew(1, 2, 3, 4);
+    final String expectedMessage = "Mixing the immutable stew we find: 1 potatoes, " +
+            "2 carrots, 3 meat and 4 peppers";
+
+    final InOrder inOrder = inOrder(getStdOutMock());
+    for (int i = 0; i < 20; i++) {
+      stew.mix();
+      inOrder.verify(getStdOutMock()).println(expectedMessage);
+    }
+
+    inOrder.verifyNoMoreInteractions();
+  }
+
+}