SpringBoot 2 + Junit5: null with #Value - spring-boot

Question

I have an application with SpringBoot2 and Junit5, and now I'm trying to make a test. I have a this class called OrderService that looks like this:
#Component
public class OrderService {
#Value("#{'${food.requires.box}'.split(',')}")
private List<String> foodRequiresBox;
#Value("#{'${properties.prioritization}'.split(',')}")
private List<String> prioritizationProperties;
#Value("${further.distance}")
private Integer slotMeterRange;
#Value("${slot.meters.long}")
private Double slotMetersLong;
As you can see, the class has many #Value annotations that extracts values from application.properties file.
In the POM file I have these dependences:
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.0.1.RELEASE</version>
</parent>
<dependencies>
<dependency>
<groupId>org.junit.jupiter</groupId>
<artifactId>junit-jupiter-engine</artifactId>
<version>5.1.0</version>
</dependency>
<dependency>
<groupId>org.junit.jupiter</groupId>
<artifactId>junit-jupiter-api</artifactId>
<version>RELEASE</version>
</dependency>
<dependency>
<groupId>org.junit.platform</groupId>
<artifactId>junit-platform-launcher</artifactId>
<version>1.1.0</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
<version>2.0.5.RELEASE</version>
</dependency>
Tn the test/resources folder I have the application.properties file with this information:
properties.prioritization:vip,food
food.requires.box:pizza,cake,flamingo
further.distance:2
slot.meters.long:0.5
The test file looks like this:
#ExtendWith(SpringExtension.class)
#TestPropertySource(locations="classpath:application.properties")
public class OrderServiceTest {
OrderService orderService;
#BeforeEach
void before(){
orderService = new OrderService();
}
#Test
void findAll() {
Order order = new Order().withDescription("2x Pizza with Salad\\n2x Kebab with Fries\\n1x Hot dog with Fries\\n2x Pizza with Fries");
assertTrue(orderService.orderHasFood.test(order));
}
}
But the test throws NullPointerException when it tries to use foodRequiresBox, so there is a problem to read the application.properties file.
Could you tell how can I read the application.properties file for the tests?

Answer 1

1st Solution
I would recommend to use Spring's internal annotation called #SpringJUnitConfig
This annotation is actually the same as #ExtendWith(SpringExtension.class) BUT you can configure your spring application contexts for your test in the same way you used to use #ContextConfiguration.
Or if you want a full Spring Boot Test you could just combine:
#SpringJUnitConfig
#SpringBootTest
public class OrderServiceTest {
...
}
2nd Solution
Another way is to not use Spring at all, but mock all the internal stuff with e.g. Mockito and write a plain simple Unit Test.
You could then set your normally via Spring injected annotated #Value fields via org.springframework.test.util.ReflectionTestUtils.

Answer 2

I'd recommend using org.springframework.test.util.ReflectionTestUtils (as indicated in #mrkernelpanic second solution) using the setField() method, in order to avoid initializing the full Spring context.
Here is a snippet:
// ReflexionTestUtils.setField(targetObject, "targetFieldName", valueToInject);
ReflexionTestUtils.setField(orderService, "foodRequiresBox", "pizza,cake,flamingo");