How Do I Unit Test A Jersey REST API Without Running A Server? - spring-boot

Question

I am working with a REST API that is using Jersey with Spring Boot (so no specific application context in XML or Java) and Spring Data JPA.
I want to write unit tests on the GET and POST endpoints, however, I don't want to start a web server as it takes too long.
If I use JerseyTest my Spring Beans don't get loaded into the context.
public class InMemoryContainerPackageTest extends
JerseyTestNg.ContainerPerClassTest {
#Override
protected TestContainerFactory getTestContainerFactory() {
return new InMemoryTestContainerFactory();
}
#Override
public Application configure() {
ResourceConfig config = new ResourceConfig()
.register(SpringLifecycleListener.class)
.register(RequestContextFilter.class)
.register(this)
.register(MyController.class)
.packages("com.my.service");
return config;
}
If I use SpringBootTest it starts up a web server which takes about 30 seconds and ideally I want all my tests to complete in under 5 seconds otherwise developers won't run them.
#SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
public class TestNGClass1 extends AbstractTestNGSpringContextTests {
I don't think MockMvc works with Jersey endpoints.

Answer 1

If I use JerseyTest my Spring Beans don't get loaded into the context.
What you can do is set the property "contextConfig" in your ResourceConfig. The value will be a Spring ApplicationContext instance. So if you are using Java configuration, you would just use an AnnotationConfigApplicationContext.
#Override
public ResourceConfig configure() {
return new ResourceConfig()
.register(TestResource.class)
.property("contextConfig",
new AnnotationConfigApplicationContext(SpringConfig.class));
}
Here, SpringConfig is an arbitrary Spring #Configuration class. Below is a complete example.
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.core.Response;
import org.glassfish.jersey.server.ResourceConfig;
import org.glassfish.jersey.test.JerseyTest;
import org.glassfish.jersey.test.inmemory.InMemoryTestContainerFactory;
import org.glassfish.jersey.test.spi.TestContainerFactory;
import org.junit.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import static org.assertj.core.api.Assertions.assertThat;
public class SpringTest extends JerseyTest {
public static class MessageService {
public String getMessage() {
return "Hello World";
}
}
#Configuration
public static class SpringConfig {
#Bean
public MessageService service() {
return new MessageService();
}
}
#Path("test")
public static class TestResource {
#Autowired
private MessageService service;
#GET
public String get() {
return service.getMessage();
}
}
#Override
public ResourceConfig configure() {
return new ResourceConfig()
.register(TestResource.class)
.property("contextConfig",
new AnnotationConfigApplicationContext(SpringConfig.class));
}
#Override
public TestContainerFactory getTestContainerFactory() {
return new InMemoryTestContainerFactory();
}
#Test
public void testIt() {
Response res = target("test")
.request()
.get();
String msg = res.readEntity(String.class);
System.out.println(msg);
assertThat(msg).isEqualTo("Hello World");
}
}
As far as the JPA, you are going to have to configure that yourself. When using Spring Boot, all of the JPA bootstrapping is taken care of. If you are going to use Jersey Test Framework, then you are ignoring all Spring Boot configuration.
It's really not that hard to configure JPA yourself. It basically consists of configuring a DataSource, a TransactionManager, a JpaVendorAdaptor, and a LocalContainerEntityManagerFactoryBean. And to enable the Spring Data repositories, you just need to use the #EnableJpaRepositories.
Have a look at this complete example configuration.
Another thing to be wary of is that when we use the Jersey Test Framework, we will not have the test scoped transactions (and rollbacks) that you will get when working with Spring Test. So when you write your tests, you need to take this into consideration.