Dynamic SpringBootTest properties

[codefromthecrypt]

There's currently means to assign a dynamic port to the Spring Boot Server under test. When doing micro-integration (side-effect) tests, we a dynamic endpoint for a dependent services. For example, I want to start a fake google service and have Spring Boot use the endpoint to that. Currently, it is not straightforward to wire in a dynamic property like "cloud.endpoint". Neither is it possible for SpringBootTest to pick extra ports: if SpringBootTest could pick other ports, then it could render these as properties, which the fake servers could use in the test.

like here's one idea..

@SpringBootTest(bootstrapProperties = AssignGooglePort.class, ...)
--snip--

static class AssignGooglePort implements Something {
  @Override public void someCallback(ConfigurableApplicationContext context){
    int port = somePortPicker.pick();
    EnvironmentTestUtils.addEnvironment(context,
        "google.endpoint:http://host1:"+port
    );
  }
}

// then the test could read the bootstrapped property by injecting it

Regardless of the solution pattern, it would be great to have SpringBootTest collaborate with other services (which themselves may or may not be Spring Boot).

cc @denyska @marcingrzejszczak

openzipkin/zipkin-gcp#16 (comment)

[philwebb]

Do you mean that you want an arbitrary random port to be assigned when the test starts that you can then inject later to use? Something that's a combination of @TestPropertySource and SocketUtils.findAvailableTcpPort?

@RunWith(SpringRunner.class)
@SpringBootTest
@RandomPortProperty("google.endpoint.port")
public class MyTest {

}

public class AppConfig {

    @Bean
    public GoogleService(@Value("${google.endpoint.port:1234}") int port) {
        return new GoogleService(port);
    }

}

i.e. Taking this code (that will run with the current release) and making it a bit easier to use:

import org.junit.Test;
import org.junit.runner.RunWith;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.test.context.PortTest.RandomPortInitailizer;
import org.springframework.context.ApplicationContextInitializer;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringRunner;
import org.springframework.test.context.support.TestPropertySourceUtils;
import org.springframework.util.SocketUtils;

import static org.assertj.core.api.Assertions.assertThat;

@RunWith(SpringRunner.class)
@SpringBootTest
@ContextConfiguration(initializers = RandomPortInitailizer.class)
public class PortTest {

	@Autowired
	private SomeService service;

	@Test
	public void testName() throws Exception {
		System.out.println(this.service);
		assertThat(this.service.toString()).containsOnlyDigits();
	}

	@Configuration
	static class MyConfig {

		@Bean
		public SomeService someService(@Value("${my.random.port}") int port) {
			return new SomeService(port);
		}

	}

	static class SomeService {

		private final int port;

		public SomeService(int port) {
			this.port = port;
		}

		@Override
		public String toString() {
			return String.valueOf(this.port);
		}

	}

	public static class RandomPortInitailizer
			implements ApplicationContextInitializer<ConfigurableApplicationContext> {

		@Override
		public void initialize(ConfigurableApplicationContext applicationContext) {
			int randomPort = SocketUtils.findAvailableTcpPort();
			TestPropertySourceUtils.addInlinedPropertiesToEnvironment(applicationContext,
					"my.random.port=" + randomPort);
		}

	}

}

[spencergibb]

We do something similar a number of times in Spring Cloud

[codefromthecrypt]

thanks for the tips, this looks like it would do the trick! will try

[denyska]

Thanks for the tip, custom initializer will work for sure! How about adding 'tcpport' method to RandomValuePropertySource to make properties read my.random.port=${random.tcpport}?

[vanhove]

I tried this out with spring boot 1.5.2 and combining those 2 annotation don't work. The initializer is ignored.

@SpringBootTest
@ContextConfiguration(initializers = RandomPortInitailizer.class)

And apparently it works in version 1.5.3 :-p