BAEL-6221 Get Mocks from MockedConstruction in Mockito (#14776)

JonCook · jcook02 · web-flow · commit 2e58e30ffa74 · 2023-09-19T18:51:33.000+02:00
Co-authored-by: jcook02 &lt;jonathan.paul.cook@ext.esa.int&gt;
diff --git a/testing-modules/mockito-2/src/main/java/com/baeldung/construction/CoffeeMachine.java b/testing-modules/mockito-2/src/main/java/com/baeldung/construction/CoffeeMachine.java
@@ -0,0 +1,23 @@
+package com.baeldung.construction;
+
+public class CoffeeMachine {
+
+    private Grinder grinder;
+    private WaterTank tank;
+
+    public CoffeeMachine() {
+        this.grinder = new Grinder();
+        this.tank = new WaterTank();
+    }
+    
+    public CoffeeMachine(int mils) {
+        this.grinder = new Grinder();
+        this.tank = new WaterTank(mils);
+    }
+
+    public String makeCoffee() {
+        String type = this.tank.isEspresso() ? "Espresso" : "Americano";
+        return String.format("Finished making a delicious %s made with %s beans", type, this.grinder.getBeans());
+    }
+
+}
diff --git a/testing-modules/mockito-2/src/main/java/com/baeldung/construction/Fruit.java b/testing-modules/mockito-2/src/main/java/com/baeldung/construction/Fruit.java
@@ -0,0 +1,12 @@
+package com.baeldung.construction;
+
+public class Fruit {
+    
+    public String getName() {
+        return "Apple";
+    }
+
+    public String getColour() {
+        return "Red";
+    }
+}
diff --git a/testing-modules/mockito-2/src/main/java/com/baeldung/construction/Grinder.java b/testing-modules/mockito-2/src/main/java/com/baeldung/construction/Grinder.java
@@ -0,0 +1,19 @@
+package com.baeldung.construction;
+
+public class Grinder {
+
+    private String beans;
+
+    public Grinder() {
+        this.beans = "Guatemalan";
+    }
+
+    public String getBeans() {
+        return beans;
+    }
+
+    public void setBeans(String beans) {
+        this.beans = beans;
+    }
+
+}
diff --git a/testing-modules/mockito-2/src/main/java/com/baeldung/construction/WaterTank.java b/testing-modules/mockito-2/src/main/java/com/baeldung/construction/WaterTank.java
@@ -0,0 +1,27 @@
+package com.baeldung.construction;
+
+public class WaterTank {
+
+    private int mils;
+
+    public WaterTank() {
+        this.mils = 25;
+    }
+    
+    public WaterTank(int mils) {
+        this.mils = mils;
+    }
+
+    public int getMils() {
+        return mils;
+    }
+
+    public void setMils(int mils) {
+        this.mils = mils;
+    }
+
+    public boolean isEspresso() {
+        return getMils() < 50;
+    }
+
+}
diff --git a/testing-modules/mockito-2/src/test/java/com/baeldung/construction/CoffeeMachineUnitTest.java b/testing-modules/mockito-2/src/test/java/com/baeldung/construction/CoffeeMachineUnitTest.java
@@ -0,0 +1,56 @@
+package com.baeldung.construction;
+
+import static org.junit.jupiter.api.Assertions.*;
+import static org.mockito.Mockito.mockConstruction;
+import static org.mockito.Mockito.when;
+
+import org.junit.jupiter.api.Test;
+import org.mockito.MockedConstruction;
+
+class CoffeeMachineUnitTest {
+
+    @Test
+    void givenNoMockedContructor_whenCoffeeMade_thenRealDependencyReturned() {
+        CoffeeMachine machine = new CoffeeMachine();
+        assertEquals("Finished making a delicious Espresso made with Guatemalan beans", machine.makeCoffee());
+    }
+
+    @Test
+    void givenMockedContructor_whenCoffeeMade_thenMockDependencyReturned() {
+        try (MockedConstruction<WaterTank> mockTank = mockConstruction(WaterTank.class); MockedConstruction<Grinder> mockGrinder = mockConstruction(Grinder.class)) {
+
+            CoffeeMachine machine = new CoffeeMachine();
+
+            WaterTank tank = mockTank.constructed()
+                .get(0);
+            Grinder grinder = mockGrinder.constructed()
+                .get(0);
+
+            when(tank.isEspresso()).thenReturn(false);
+            when(grinder.getBeans()).thenReturn("Peruvian");
+
+            assertEquals("Finished making a delicious Americano made with Peruvian beans", machine.makeCoffee());
+        }
+
+    }
+
+    @Test
+    void givenMockedContructorWithArgument_whenCoffeeMade_thenMockDependencyReturned() {
+        try (MockedConstruction<WaterTank> mockTank = mockConstruction(WaterTank.class, (mock, context) -> {
+                int mils = (int) context.arguments().get(0);
+                when(mock.getMils()).thenReturn(mils);         
+            }); 
+            MockedConstruction<Grinder> mockGrinder = mockConstruction(Grinder.class)) {
+
+            CoffeeMachine machine = new CoffeeMachine(100);
+
+            Grinder grinder = mockGrinder.constructed()
+                .get(0);
+
+            when(grinder.getBeans()).thenReturn("Kenyan");
+            assertEquals("Finished making a delicious Americano made with Kenyan beans", machine.makeCoffee());
+        }
+
+    }
+
+}
diff --git a/testing-modules/mockito-2/src/test/java/com/baeldung/construction/FruitUnitTest.java b/testing-modules/mockito-2/src/test/java/com/baeldung/construction/FruitUnitTest.java
@@ -0,0 +1,50 @@
+package com.baeldung.construction;
+
+import org.junit.jupiter.api.Test;
+import org.mockito.Answers;
+import org.mockito.MockedConstruction;
+
+import static org.mockito.Mockito.when;
+import static org.mockito.Mockito.withSettings;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.List;
+
+import static org.mockito.Mockito.mockConstruction;
+
+class FruitUnitTest {
+
+    @Test
+    void givenMockedContructor_whenFruitCreated_thenMockIsReturned() {
+        assertEquals("Apple", new Fruit().getName());
+        assertEquals("Red", new Fruit().getColour());
+
+        try (MockedConstruction<Fruit> mock = mockConstruction(Fruit.class)) {
+
+            Fruit fruit = new Fruit();
+            when(fruit.getName()).thenReturn("Banana");
+            when(fruit.getColour()).thenReturn("Yellow");
+
+            assertEquals("Banana", fruit.getName());
+            assertEquals("Yellow", fruit.getColour());
+
+            List<Fruit> constructed = mock.constructed();
+            assertEquals(1, constructed.size());
+        }
+    }
+    
+    @Test
+    void givenMockedContructorWithNewDefaultAnswer_whenFruitCreated_thenRealMethodInvoked() {
+        try (MockedConstruction<Fruit> mock = mockConstruction(Fruit.class, withSettings().defaultAnswer(Answers.CALLS_REAL_METHODS))) {
+
+            Fruit fruit = new Fruit();
+
+            assertEquals("Apple", fruit.getName());
+            assertEquals("Red", fruit.getColour());
+
+            List<Fruit> constructed = mock.constructed();
+            assertEquals(1, constructed.size());
+        }
+    }
+
+}
