[email protected] Mocking a Method in the Same Test Class Using Mockito Spy (#18047)

* adding spy methods

* modifications following review

* move to new mockito 4 module

* merge in one class

* remove print

---------

Co-authored-by: rim <[email protected]>

Author: rimow

testing-modules/mockito-4/src/main/java/com/baeldung/spymethods/CatTantrum.java

@@ -0,0 +1,35 @@
+package com.baeldung.spymethods;
+
+public class CatTantrum {
+
+    public enum CatAction {
+        BITE,
+        MEOW,
+        VOMIT_ON_CARPET,
+        EAT_DOGS_FOOD,
+        KNOCK_THING_OFF_TABLE
+    }
+    public enum HumanReaction {
+        SCREAM,
+        CRY,
+        CLEAN,
+        PET_ON_HEAD,
+        BITE_BACK,
+    }
+
+    public HumanReaction whatIsHumanReaction(CatAction action){
+        return switch (action) {
+            case MEOW -> HumanReaction.PET_ON_HEAD;
+            case VOMIT_ON_CARPET -> HumanReaction.CLEAN;
+            case EAT_DOGS_FOOD -> HumanReaction.SCREAM;
+            case KNOCK_THING_OFF_TABLE -> HumanReaction.CRY;
+            case BITE -> biteCatBack();
+        };
+    }
+
+    public HumanReaction biteCatBack() {
+        // Some logic
+        return HumanReaction.BITE_BACK;
+    }
+
+}

testing-modules/mockito-4/src/test/java/com/baeldung/spymethods/CatTantrumUnitTest.java

@@ -0,0 +1,26 @@
+import com.baeldung.spymethods.CatTantrum;
+import com.baeldung.spymethods.CatTantrum.CatAction;
+import com.baeldung.spymethods.CatTantrum.HumanReaction;
+import org.junit.jupiter.api.Test;
+import org.mockito.Mockito;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.mockito.Mockito.when;
+
+public class CatTantrumUnitTest {
+
+    @Test
+    public void givenMockMethodHumanReactions_whenCatActionBite_thenHumanReactionsBiteBack(){
+        //Given
+        CatTantrum catTantrum = new CatTantrum();
+        CatTantrum catTantrum1 = Mockito.spy(catTantrum);
+        Mockito.doReturn(HumanReaction.BITE_BACK).when(catTantrum1).biteCatBack();
+
+        //When
+        HumanReaction humanReaction1 = catTantrum1.whatIsHumanReaction(CatAction.BITE);
+
+        //Then
+        assertEquals(humanReaction1, HumanReaction.BITE_BACK);
+    }
+
+}