How to fetch parameters from the application.properties file for a test case

Question

I have the following Controller class

@Component
public class Controller{
@Value("${details}")
private String detail1;
@Value("${otherdetails}")
private String detail2;
public ModelClass getSomeDetails(String name, int age) {
 Serviceclass serviceobject = new Serviceclass();
 //some Code
 serviceobject.doSomething(name, age, detail1, detail2);
 }
}

Once this is done, I need to test this method in a test case. My test class is as below. I have the application.properties file in the /src/test/resources folder

@RunWith(SpringJUnit4ClassRunner.class)
@TestPropertySource(locations="classpath:application.properties")
public class testClass{
@Test
public void getDetails() {
Controller controllerObject = new Controller();
controllerObject.getSomeDetails("name", 22);
//Other code
 }
}

When I do this, the application.properties has the details and otherdetails parameter but it is returning null.

How should I use them to get the value in the Controller class?

• Vishwa Ratna: src\main\resources\application.properties is the structure right??
• evan: Yes, I have the file in that location as well. since that did not work, I have over-ridden the properties file by creating a new file under the above mentioned location
• Vishwa Ratna: @rjdkolb , @TestPropertySource(locations="classpath:application.properties") should be fine.

Answer 1

Do not manually instantiate the controller, rather AutoWire the controller into your test class.

@RunWith(SpringJUnit4ClassRunner.class)
@TestPropertySource(locations="classpath:application.properties")
public class testClass{
@Autowired Controller controllerObject;
@Test
public void getDetails() {
controllerObject.getSomeDetails("name", 22);
//Other code
 }
}

• evan: Doing this was not successful either. I ended up with UnsatisfiedDependencyException where error creating bean with name "...controller.testClass"

Answer 2

You need to let Spring instantiate your Controller class and not manually do a new yourself:

@RunWith(SpringJUnit4ClassRunner.class)
@TestPropertySource(locations="classpath:application.properties")
public class testClass{
 @Autowired
 private Controller controllerObject;
 @Test
 public void getDetails() {
 controllerObject.getSomeDetails("name", 22);
 //Other code
 }
 @TestConfiguration
 static class TestConfig {
 @Bean
 public Controller controller() {
 return new Controller();
 }
 }
}

Note that you can also replace @RunWith(SpringJUnit4ClassRunner.class) with @RunWith(SpringRunner.class).

Instead of adding the inner class, you can also have Spring test start your complete application by annotating the test with @SpringBootTest. If you know what part of your application you want to test, you can get better performance by using test slicing.

• evan: Doing this was not successful either. I ended up with UnsatisfiedDependencyException where error creating bean with name "...controller.testClass"
• evan: The above is error free with adding @SpringBootTest, but I still get null for the values from the property files
• Wim Deblauwe: @evan I suggest you create a sample application to further investigate the issue. You can also manually configure the values to use in the test with @TestPropertySource(properties="details=x"). See baeldung.com/spring-test-property-source