BAEL-5777 - Mocking a singleton with Mockito (#12977)

* BAEL-5777 - Mocking a singleton with Mockito

* BAEL-5777 - Mocking a singleton with Mockito - changing test class name

* BAEL-5777 - Mocking a singleton with Mockito - moving to new module

testing-modules/mockito-2/src/test/java/com/baeldung/singleton/ProductServiceTest.java

@@ -0,0 +1,40 @@
+package com.baeldung.singleton;
+
+import org.junit.jupiter.api.Test;
+import org.mockito.MockedStatic;
+import org.mockito.Mockito;
+
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.*;
+
+class ProductServiceUnitTest {
+
+    @Test
+    void givenValueExistsInCache_whenGetProduct_thenDAOIsNotCalled() {
+        ProductDAO productDAO = mock(ProductDAO.class);
+        CacheManager cacheManager = mock(CacheManager.class);
+        Product product = new Product("product1", "description");
+        ProductService productService = new ProductService(productDAO, cacheManager);
+
+        when(cacheManager.getValue(any(), any())).thenReturn(product);
+
+        productService.getProduct("product1");
+
+        Mockito.verify(productDAO, times(0)).getProduct(any());
+    }
+
+    @Test
+    void givenValueExistsInCache_whenGetProduct_thenDAOIsNotCalled_mockingStatic() {
+        ProductDAO productDAO = mock(ProductDAO.class);
+        CacheManager cacheManager = mock(CacheManager.class);
+        Product product = new Product("product1", "description");
+
+        try (MockedStatic<CacheManager> cacheManagerMock = mockStatic(CacheManager.class)) {
+            cacheManagerMock.when(CacheManager::getInstance).thenReturn(cacheManager);
+            when(cacheManager.getValue(any(), any())).thenReturn(product);
+            ProductService productService = new ProductService(productDAO);
+            productService.getProduct("product1");
+            Mockito.verify(productDAO, times(0)).getProduct(any());
+        }
+    }
+}

testing-modules/mockito-2/src/test/resources/mockito-extensions/org.mockito.plugins.MockMaker

@@ -0,0 +1 @@
+mock-maker-inline