BAEL-2293: Guide to ReflectionTestUtils and uses in Unit Testing (eugenp#5681)

* BAEL-2293: Guide to ReflectionTestUtils and uses in Unit Testing * BAEL-2293: Guide to ReflectionTestUtils and uses in Unit Testing * BAEL-2293: Guide to ReflectionTestUtils and uses in Unit Testing * Update ReflectionTestUtilsUnitTest.java

Author: codehunter34

testing-modules/spring-testing/src/main/java/org/baeldung/reflectiontestutils/repository/Employee.java

@@ -0,0 +1,23 @@
+package org.baeldung.reflectiontestutils.repository;
+
+public class Employee {
+ private Integer id;
+ private String name;
+
+ public Integer getId() {
+ return id;
+ }
+
+ public String getName() {
+ return name;
+ }
+
+ public void setName(String name) {
+ this.name = name;
+ }
+
+ private String employeeToString() {
+ return "id: " + getId() + "; name: " + getName();
+ }
+
+}

testing-modules/spring-testing/src/main/java/org/baeldung/reflectiontestutils/repository/EmployeeService.java

@@ -0,0 +1,14 @@
+package org.baeldung.reflectiontestutils.repository;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Component;
+
+@Component
+public class EmployeeService {
+ @Autowired
+ private HRService hrService;
+
+ public String findEmployeeStatus(Integer employeeId) {
+ return "Employee " + employeeId + " status: " + hrService.getEmployeeStatus(employeeId);
+ }
+}

testing-modules/spring-testing/src/main/java/org/baeldung/reflectiontestutils/repository/HRService.java

@@ -0,0 +1,11 @@
+package org.baeldung.reflectiontestutils.repository;
+
+import org.springframework.stereotype.Component;
+
+@Component
+public class HRService {
+
+ public String getEmployeeStatus(Integer employeeId) {
+ return "Inactive";
+ }
+}

testing-modules/spring-testing/src/test/java/org/baeldung/reflectiontestutils/ReflectionTestUtilsUnitTest.java

@@ -0,0 +1,46 @@
+package org.baeldung.reflectiontestutils;
+
+import static org.junit.Assert.*;
+import static org.mockito.Mockito.mock;
+
+import org.baeldung.reflectiontestutils.repository.Employee;
+import org.baeldung.reflectiontestutils.repository.EmployeeService;
+import org.baeldung.reflectiontestutils.repository.HRService;
+import org.junit.Test;
+import org.springframework.test.util.ReflectionTestUtils;
+
+import static org.mockito.Mockito.when;
+
+public class ReflectionTestUtilsUnitTest {
+
+ @Test
+ public void whenNonPublicField_thenReflectionTestUtilsSetField() {
+ Employee employee = new Employee();
+ ReflectionTestUtils.setField(employee, "id", 1);
+ assertTrue(employee.getId().equals(1));
+
+ }
+
+ @Test
+ public void whenNonPublicMethod_thenReflectionTestUtilsInvokeMethod() {
+ Employee employee = new Employee();
+ ReflectionTestUtils.setField(employee, "id", 1);
+ employee.setName("Smith, John");
+ assertTrue(ReflectionTestUtils.invokeMethod(employee, "employeeToString").equals("id: 1; name: Smith, John"));
+ }
+
+ @Test
+ public void whenInjectingMockOfDependency_thenReflectionTestUtilsSetField() {
+ Employee employee = new Employee();
+ ReflectionTestUtils.setField(employee, "id", 1);
+ employee.setName("Smith, John");
+
+ HRService hrService = mock(HRService.class);
+ when(hrService.getEmployeeStatus(employee.getId())).thenReturn("Active");
+ EmployeeService employeeService = new EmployeeService();
+
+ // Inject mock into the private field
+ ReflectionTestUtils.setField(employeeService, "hrService", hrService);
+ assertEquals("Employee " + employee.getId() + " status: Active", employeeService.findEmployeeStatus(employee.getId()));
+ }
+}