refactor: Declares the template method as final (Issue 1099) (#2057)

template-method/README.md

@@ -39,6 +39,10 @@ Wikipedia says
 **Programmatic Example**
 
 Let's first introduce the template method class along with its concrete implementations.
+To make sure that subclasses don’t override the template method, the template method (in our case
+method `steal`) should be declared `final`, otherwise the skeleton defined in the base class could
+be overridden in subclasses.
+
 
 ```java
 @Slf4j
@@ -50,7 +54,7 @@ public abstract class StealingMethod {
 
   protected abstract void stealTheItem(String target);
 
-  public void steal() {
+  public final void steal() {
     var target = pickTarget();
     LOGGER.info("The target has been chosen as {}.", target);
     confuseTarget(target);

template-method/pom.xml

@@ -41,7 +41,7 @@
     </dependency>
     <dependency>
       <groupId>org.mockito</groupId>
-      <artifactId>mockito-core</artifactId>
+      <artifactId>mockito-inline</artifactId>
       <scope>test</scope>
     </dependency>
   </dependencies>

template-method/src/main/java/com/iluwatar/templatemethod/StealingMethod.java

@@ -41,7 +41,7 @@ public abstract class StealingMethod {
   /**
    * Steal.
    */
-  public void steal() {
+  public final void steal() {
     var target = pickTarget();
     LOGGER.info("The target has been chosen as {}.", target);
     confuseTarget(target);

template-method/src/test/java/com/iluwatar/templatemethod/HalflingThiefTest.java

@@ -24,7 +24,7 @@
  */
 package com.iluwatar.templatemethod;
 
-import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.spy;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.verifyNoMoreInteractions;
 
@@ -42,11 +42,14 @@ public class HalflingThiefTest {
    */
   @Test
   void testSteal() {
-    final var method = mock(StealingMethod.class);
+    final var method = spy(StealingMethod.class);
     final var thief = new HalflingThief(method);
 
     thief.steal();
     verify(method).steal();
+    String target = verify(method).pickTarget();
+    verify(method).confuseTarget(target);
+    verify(method).stealTheItem(target);
 
     verifyNoMoreInteractions(method);
   }
@@ -56,19 +59,23 @@ public class HalflingThiefTest {
    */
   @Test
   void testChangeMethod() {
-    final var initialMethod = mock(StealingMethod.class);
+    final var initialMethod = spy(StealingMethod.class);
     final var thief = new HalflingThief(initialMethod);
 
     thief.steal();
     verify(initialMethod).steal();
+    String target = verify(initialMethod).pickTarget();
+    verify(initialMethod).confuseTarget(target);
+    verify(initialMethod).stealTheItem(target);
 
-    final var newMethod = mock(StealingMethod.class);
+    final var newMethod = spy(StealingMethod.class);
     thief.changeMethod(newMethod);
 
     thief.steal();
     verify(newMethod).steal();
-
+    String newTarget = verify(newMethod).pickTarget();
+    verify(newMethod).confuseTarget(newTarget);
+    verify(newMethod).stealTheItem(newTarget);
     verifyNoMoreInteractions(initialMethod, newMethod);
-
   }
 }