Tuesday, July 22, 2014

Spring: Integration testing under Spring Boot application context but mocking services

So I wanted to create some integration tests for an API application that uses Spring Boot. The thing is that I needed to load the same application context as the real applicationm, because Spring Boot performs a bunch of configurations for you, and these were not being loaded in a StandAlone mode.

But also I didn't want to use real services which depend upon real data. Depending on databases for your tests creates fragile tests.

After researching on the web I found this way:


This is the typical Spring-Boot entry point class.

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.context.annotation.ComponentScan;

@EnableAutoConfiguration
@ComponentScan
public class MyApplication {

    public static void main(String[] args) {
        SpringApplication.run(MyApplication.class, args);
    }
}

A base class having the logic to init the application context.

import static org.springframework.test.web.servlet.setup.MockMvcBuilders.webAppContextSetup;
import org.junit.Before;
import org.junit.runner.RunWith;
import org.mockito.MockitoAnnotations;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.SpringApplicationConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import org.springframework.test.context.web.WebAppConfiguration;
import org.springframework.test.web.servlet.MockMvc;
import org.springframework.web.context.WebApplicationContext;

@RunWith(SpringJUnit4ClassRunner.class)
@WebAppConfiguration
@SpringApplicationConfiguration(classes = MyApplication.class)
public abstract class BaseIntegrationTest {

    protected MockMvc mockMvc;
    
    @Autowired
    protected WebApplicationContext wac;

    @Before
    public void setup() {
       
        MockitoAnnotations.initMocks(this);
        this.mockMvc = webAppContextSetup(wac).build();
    }
}

An implementation class mocking a required service class.
public class FooIntegrationTest extends BaseIntegrationTest {

    @Configuration
    public static class TestConfiguration {
        @Bean
        @Primary
        public FooService fooService() {
            return mock(FooService.class);
        }
    }


    @Autowired
    FooService mockFooService;
}