Merge pull request #18423 from hmdrzsharifi/BAEL-8669

BAEL-8669: Improve article "Mock Final Classes and Methods with Mockito"

Author: davidmartinezbarua

testing-modules/junit-5/pom.xml

@@ -74,8 +74,17 @@
                     <groupId>junit</groupId>
                     <artifactId>junit</artifactId>
                 </exclusion>
+                <exclusion>
+                    <groupId>org.javassist</groupId>
+                    <artifactId>javassist</artifactId>
+                </exclusion>
             </exclusions>
         </dependency>
+        <dependency>
+            <groupId>org.javassist</groupId>
+            <artifactId>javassist</artifactId>
+            <version>${javassist.version}</version>
+        </dependency>
         <dependency>
             <groupId>org.mockito</groupId>
             <artifactId>mockito-junit-jupiter</artifactId>
@@ -125,6 +134,8 @@
                     <argLine>
                         --add-opens java.base/java.lang=ALL-UNNAMED
                         --add-opens java.base/java.time=ALL-UNNAMED
+                        --add-opens java.base/java.time.format=ALL-UNNAMED
+                        --add-opens java.base/java.util=ALL-UNNAMED
                     </argLine>
                 </configuration>
             </plugin>
@@ -136,6 +147,7 @@
         <powermock.version>2.0.9</powermock.version>
         <spring.version>5.0.1.RELEASE</spring.version>
         <mockito.version>3.3.0</mockito.version> <!--Cannot upgrade to the latest version as powermock doesn't support that-->
+        <javassist.version>3.30.2-GA</javassist.version> <!--Cannot upgrade to the latest version as powermock doesn't support that-->
     </properties>
 
 </project>

testing-modules/junit-5/src/main/java/com/baeldung/mockfinal/FinalList.java

@@ -0,0 +1,10 @@
+package com.baeldung.mockfinal;
+
+public final class FinalList extends MyList {
+
+    @Override
+    public int size() {
+        return 1;
+    }
+
+}

testing-modules/junit-5/src/main/java/com/baeldung/mockfinal/MyList.java

@@ -0,0 +1,25 @@
+package com.baeldung.mockfinal;
+
+import java.util.AbstractList;
+
+public class MyList extends AbstractList<String> {
+
+    @Override
+    public String get(final int index) {
+        return null;
+    }
+
+    @Override
+    public int size() {
+        return 1;
+    }
+
+    @Override
+    public void add(int index, String element) {
+        // no-op
+    }
+
+    final public int finalMethod() {
+        return 0;
+    }
+}

testing-modules/junit-5/src/test/java/com/baeldung/mockfinal/PowerMockFinalsUnitTest.java

@@ -0,0 +1,32 @@
+package com.baeldung.mockfinal;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.powermock.api.mockito.PowerMockito;
+import org.powermock.core.classloader.annotations.PrepareForTest;
+import org.powermock.modules.junit4.PowerMockRunner;
+
+import static org.assertj.core.api.AssertionsForClassTypes.assertThat;
+import static org.powermock.api.mockito.PowerMockito.when;
+
+@RunWith(PowerMockRunner.class)
+@PrepareForTest({MyList.class, FinalList.class})
+public class PowerMockFinalsUnitTest {
+
+    @Test
+    public void whenMockFinalMethod_thenMockWorks() throws Exception {
+        MyList mockClass = PowerMockito.mock(MyList.class);
+        when(mockClass.finalMethod()).thenReturn(1);
+
+        assertThat(mockClass.finalMethod()).isNotZero();
+    }
+
+    @Test
+    public void whenMockFinalClass_thenMockWorks() throws Exception {
+        FinalList mockClass = PowerMockito.mock(FinalList.class);
+        when(mockClass.size()).thenReturn(2);
+
+        assertThat(mockClass.size()).isNotEqualTo(1);
+    }
+
+}