Testing With a Running Server

If you need to start a full running server, we recommend that you use random ports. If you use @SpringBootTest(webEnvironment=WebEnvironment.RANDOM_PORT), an available port is picked at random each time your test runs.

The @LocalServerPort annotation can be used to inject the actual port used into your test. For convenience, tests that need to make REST calls to the started server can additionally @Autowire a WebTestClient, which resolves relative links to the running server and comes with a dedicated API for verifying responses, as shown in the following example:

Java
Kotlin

import org.junit.jupiter.api.Test;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.boot.test.context.SpringBootTest.WebEnvironment;
import org.springframework.test.web.reactive.server.WebTestClient;

@SpringBootTest(webEnvironment = WebEnvironment.RANDOM_PORT)
class MyRandomPortWebTestClientTests {

	@Test
	void exampleTest(@Autowired WebTestClient webClient) {
		webClient
			.get().uri("/")
			.exchange()
			.expectStatus().isOk()
			.expectBody(String.class).isEqualTo("Hello World");
	}

}

import org.junit.jupiter.api.Test
import org.springframework.beans.factory.annotation.Autowired
import org.springframework.boot.test.context.SpringBootTest
import org.springframework.boot.test.context.SpringBootTest.WebEnvironment
import org.springframework.test.web.reactive.server.WebTestClient
import org.springframework.test.web.reactive.server.expectBody

@SpringBootTest(webEnvironment = WebEnvironment.RANDOM_PORT)
class MyRandomPortWebTestClientTests {

	@Test
	fun exampleTest(@Autowired webClient: WebTestClient) {
		webClient
			.get().uri("/")
			.exchange()
			.expectStatus().isOk
			.expectBody<String>().isEqualTo("Hello World")
	}

}

WebTestClient can be used against both live servers and mock environments.

This setup requires spring-webflux on the classpath. If you can not or will not add webflux, Spring Boot also provides a TestRestTemplate facility:

Java
Kotlin

import org.junit.jupiter.api.Test;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.boot.test.context.SpringBootTest.WebEnvironment;
import org.springframework.boot.test.web.client.TestRestTemplate;

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

@SpringBootTest(webEnvironment = WebEnvironment.RANDOM_PORT)
class MyRandomPortTestRestTemplateTests {

	@Test
	void exampleTest(@Autowired TestRestTemplate restTemplate) {
		String body = restTemplate.getForObject("/", String.class);
		assertThat(body).isEqualTo("Hello World");
	}

}

import org.assertj.core.api.Assertions.assertThat
import org.junit.jupiter.api.Test
import org.springframework.beans.factory.annotation.Autowired
import org.springframework.boot.test.context.SpringBootTest
import org.springframework.boot.test.context.SpringBootTest.WebEnvironment
import org.springframework.boot.test.web.client.TestRestTemplate

@SpringBootTest(webEnvironment = WebEnvironment.RANDOM_PORT)
class MyRandomPortTestRestTemplateTests {

	@Test
	fun exampleTest(@Autowired restTemplate: TestRestTemplate) {
		val body = restTemplate.getForObject("/", String::class.java)
		assertThat(body).isEqualTo("Hello World")
	}

}