Snippet

Mocking Service Dependencies in Controller Tests with MockBean

In Spring Boot testing, @MockBean creates a Mockito mock for a bean and registers it in the Spring ApplicationContext. This replaces actual external services (such as payment providers or third-party APIs) with predictable simulated behavior during test execution.

snippet.java

java

import org.junit.jupiter.api.Test;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.boot.test.mock.mockito.MockBean;
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.mockito.Mockito.when;
 
@SpringBootTest
public class OrderServiceTest {
 
    @MockBean
    private PaymentGateway paymentGateway;
 
    @Test
    void testSuccessfulPayment() {
        when(paymentGateway.processPayment(100.0)).thenReturn(true);
        boolean result = paymentGateway.processPayment(100.0);
        assertEquals(true, result);
    }
}

spring

Breakdown

@MockBean

Registers a Mockito mock instance into the Spring ApplicationContext to replace the real bean.

when(paymentGateway.processPayment(100.0)).thenReturn(true);

Configures the mock object to return true whenever processPayment is invoked with 100.0.

assertEquals(true, result);

Asserts that the actual returned result matches the expected test value.

Previous snippet Next snippet

More Beginner Java exercises →

Mocking Service Dependencies in Controller Tests with MockBean

Related