Mocking is a key concept in unit testing that allows developers to focus on testing the functionality of a specific unit of code, rather than its dependencies. In the context of Spring Boot applications, Mockito can be used to mock beans and services to test the functionality of a specific component without the need to launch the entire Spring context.
In this article, we'll take a look at how to use Mockito to mock beans and services in a Spring Boot application. We'll also look at how to configure Mockito to launch the Spring context automatically.
Mockito is a popular mock testing framework for Java. Mockito allows developers to create and configure mock objects to be used in unit tests. Mockito can be used to mock interfaces, classes, and even final classes and methods.
Mocking beans and services in Spring Boot is easy with Mockito. In the following example, we'll mock a bean named myBean
:
@MockBean
MyBean myBean;
@Test
public void testMyBean() {
// configure mock object
when(myBean.getName()).thenReturn("Mockito");
// invoke method on mock object
String name = myBean.getName();
// verify results
assertThat(name).isEqualTo("Mockito");
}
In the example above, we use the @MockBean
annotation to create a mock object of the MyBean
class. We then use the when
and thenReturn
methods to configure the mock object. Finally, we invoke the getName
method on the mock object and assert that the return value is as expected.
Mockito can be configured in Spring Boot using the mockito-core
and mockito-spring
dependencies. In the pom.xml
file, add the following dependencies:
<dependencies>
<dependency>
<groupId>org.mockito</groupId>
<artifactId>mockito-core</artifactId>
<version>2.13.0</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.mockito</groupId>
<artifactId>mockito-spring</artifactId>
<version>1.9.5</version>
<scope>test</scope>
</dependency>
</dependencies>
The mockito-core
dependency contains the Mockito library, while the mockito-spring
dependency contains the integration between Mockito and Spring.
In this article, we've looked at how to use Mockito to mock beans and services in a Spring Boot application. We've also seen how to configure Mockito to launch the Spring context automatically.