added missing code which are mentioned in article

spring-boot-rest/src/test/java/com/baeldung/web/FooControllerWebLayerIntegrationTest.java

@@ -10,8 +10,10 @@ import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.
 import java.util.Collections;
 
 import org.hamcrest.Matchers;
+import org.junit.Assert;
 import org.junit.Test;
 import org.junit.runner.RunWith;
+import org.mockito.Mockito;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.test.autoconfigure.web.servlet.WebMvcTest;
 import org.springframework.boot.test.mock.mockito.MockBean;
@@ -24,6 +26,7 @@ import org.springframework.test.web.servlet.MockMvc;
 import com.baeldung.persistence.model.Foo;
 import com.baeldung.persistence.service.IFooService;
 import com.baeldung.web.controller.FooController;
+import com.baeldung.web.exception.CustomException1;
 import com.baeldung.web.hateoas.event.PaginatedResultsRetrievedEvent;
 
 /**
@@ -56,5 +59,15 @@ public class FooControllerWebLayerIntegrationTest {
             .andExpect(status().isOk())
             .andExpect(jsonPath("$",Matchers.hasSize(1)));
     }
-
+    
+    @Test
+    public void delete_forException_fromService() throws Exception {
+        Mockito.when(service.findAll()).thenThrow(new CustomException1());
+        this.mockMvc.perform(get("/foos")).andDo(h ->  {
+            final Exception expectedException = h.getResolvedException();
+            Assert.assertTrue(expectedException instanceof CustomException1);
+            
+        });
+    }
+    
 }