added testPopFromEmptyStack()

src/test/java/MyStackTest.java

 import org.junit.After;
 import org.junit.Before;
+import org.junit.Rule;
 import org.junit.Test;
+import org.junit.rules.ExpectedException;
+
+import java.util.EmptyStackException;
 
 import static org.junit.Assert.*;
 
@@ -65,4 +69,35 @@ public class MyStackTest {
         stack.pop();
         assertEquals(2,stack.size());
     }
+
+    @Rule
+    public ExpectedException thrown = ExpectedException.none();
+
+    @Test
+    public void testPopFromEmptyStack() {
+        thrown.expect(EmptyStackException.class);
+        // EmptyStackExpression says it all, but if the were a constructor that took a String then we could test
+        // thrown.expectMessage("Attempted to pop from empty stack.");
+        stack.pop();
+    }
+
+/*  WILL TEST IF *ANY* CODE IN TEST METHOD THROWS EXCEPTION -- OKAY FOR SMALL TEST METHODS
+    @Test(expected = EmptyStackException.class)
+    public void testPopFromEmptyStack() {
+        stack.pop();
+    }
+*/
+
+/*  JUNIT 3 IDIOM
+    @Test
+    public void testPopFromEmptyStack() {
+        try {
+            stack.pop();
+            fail("Expected EmptyStackException to be thrown.");
+        } catch (EmptyStackException emptyStackException) {
+            // EmptyStackExpression says it all, but if the were a constructor that took a String then we could test
+            // assertThat(emptyStackExpression.getMessage(), is("Attempted to pop from empty stack."));
+        }
+    }
+*/
 }
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