How to use random port for JUNIT Testcases using Spring Boot 1.4.0 + - spring

Question

I am using spring boot 1.3.6 and my JUNIT Test cases are running fine, after upgrading to spring boot 1.4.0 and attempting to remove deprecated classes is throwing me error
My JUNITCLASS with 1.3.x
#RunWith(SpringJUnit4ClassRunner.class)
#SpringApplicationConfiguration(classes = Application.class)
#WebAppConfiguration
#IntegrationTest({"server.port=0"})
public class CustomerControllerIT {
#Value("${local.server.port}")
private int port;
private URL base;
private RestTemplate template;
#Autowired
private DataBuilder dataBuilder;
#Autowired
private CustomerRepository customerRepository;
private static final String JSON_CONTENT_TYPE = "application/json;charset=UTF-8";
#Before
public void setUp() throws Exception {
this.base = new URL("http://localhost:" + port + "/rest/customers");
template = new TestRestTemplate();
/* remove and reload test data */
customerRepository.deleteAll();
dataBuilder.createCustomers().forEach(customer -> customerRepository.save(customer));
}
#Test
public void getAllCustomers() throws Exception {
ResponseEntity<String> response = template.getForEntity(base.toString(), String.class);
assertThat(response.getStatusCode(), equalTo(HttpStatus.OK));
List<Customer> customers = convertJsonToCustomers(response.getBody());
assertThat(customers.size(), equalTo(3));
}
private List<Customer> convertJsonToCustomers(String json) throws Exception {
ObjectMapper mapper = new ObjectMapper();
return mapper.readValue(json, TypeFactory.defaultInstance().constructCollectionType(List.class, Customer.class));
}
}
MyClass with 1.4.0
Updates done
Removed deprecated TestRestTemplate with spring suggested one
Running with SpringRunner instead of SpringJUnit4ClassRunner
Replaced #SpringApplicationConfiguration(classes = Application.class) with #SpringBootTest(classes = Application.class , webEnvironment=WebEnvironment.RANDOM_PORT)
After Changes
#RunWith(SpringRunner.class)
#SpringBootTest(classes = Application.class , webEnvironment=WebEnvironment.RANDOM_PORT)
#WebAppConfiguration
public class CustomerControllerIT {
#Value("${local.server.port}")
private int port;
private URL base;
private TestRestTemplate template;
#Autowired
private DataBuilder dataBuilder;
#Autowired
private CustomerRepository customerRepository;
private static final String JSON_CONTENT_TYPE = "application/json;charset=UTF-8";
#Before
public void setUp() throws Exception {
this.base = new URL("http://localhost:" + port + "/rest/customers");
template = new TestRestTemplate();
/* remove and reload test data */
customerRepository.deleteAll();
dataBuilder.createCustomers().forEach(customer -> customerRepository.save(customer));
}
}
Now I am receiving NPE when i try to run JUNIT Testcase, How can I set the random port to make my JUNIT test case running in Spring Boot 1.4.0 +?
Update :
Here is the stacktrace of the issue
java.lang.IllegalStateException: Failed to load ApplicationContext
at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContext(DefaultCacheAwareContextLoaderDelegate.java:124)
at org.springframework.test.context.support.DefaultTestContext.getApplicationContext(DefaultTestContext.java:83)
at org.springframework.test.context.web.ServletTestExecutionListener.setUpRequestContextIfNecessary(ServletTestExecutionListener.java:189)
at org.springframework.test.context.web.ServletTestExecutionListener.prepareTestInstance(ServletTestExecutionListener.java:131)
at org.springframework.test.context.TestContextManager.prepareTestInstance(TestContextManager.java:230)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.createTest(SpringJUnit4ClassRunner.java:228)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner$1.runReflectiveCall(SpringJUnit4ClassRunner.java:287)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.methodBlock(SpringJUnit4ClassRunner.java:289)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:247)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:94)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:191)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:678)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192)
Caused by: java.lang.NullPointerException
at org.springframework.test.context.web.socket.MockServerContainerContextCustomizer.customizeContext(MockServerContainerContextCustomizer.java:38)
at org.springframework.boot.test.context.SpringBootContextLoader$ContextCustomizerAdapter.initialize(SpringBootContextLoader.java:270)
at org.springframework.boot.SpringApplication.applyInitializers(SpringApplication.java:633)
at org.springframework.boot.SpringApplication.prepareContext(SpringApplication.java:347)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:311)
at org.springframework.boot.test.context.SpringBootContextLoader.loadContext(SpringBootContextLoader.java:111)
at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContextInternal(DefaultCacheAwareContextLoaderDelegate.java:98)
at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContext(DefaultCacheAwareContextLoaderDelegate.java:116)
... 25 more

Answer 1

From Spring Blog I have updated your latest sample.
#RunWith(SpringRunner.class)
#SpringBootTest(classes = Application.class, webEnvironment=WebEnvironment.RANDOM_PORT)
public class CustomerControllerIT {
#Autowired
private TestRestTemplate template;
#Autowired
private DataBuilder dataBuilder;
#Autowired
private CustomerRepository customerRepository;
private static final String JSON_CONTENT_TYPE = "application/json;charset=UTF-8";
#Before
public void setUp() throws Exception {
/* remove and reload test data */
customerRepository.deleteAll();
dataBuilder.createCustomers().forEach(customer -> customerRepository.save(customer));
}
#Test
public void getAllCustomers() throws Exception {
ResponseEntity<String> response = template.getForEntity("/rest/customers", String.class);
assertThat(response.getStatusCode(), equalTo(HttpStatus.OK));
List<Customer> customers = convertJsonToCustomers(response.getBody());
assertThat(customers.size(), equalTo(3));
}
}

Answer 2

for JUNIT 5 the solution that worked for me is the bellow (taken from Spring's documentation):
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 org.springframework.beans.factory.annotation.Value;
import static org.assertj.core.api.Assertions.assertThat;
#SpringBootTest(webEnvironment = WebEnvironment.RANDOM_PORT)
public class HttpRequestTest {
#Value(value="${local.server.port}")
private int port;
#Autowired
private TestRestTemplate restTemplate;
#Test
public void greetingShouldReturnDefaultMessage() throws Exception {
assertThat(this.restTemplate.getForObject("http://localhost:" + port + "/",
String.class)).contains("Hello, World");
}
}
The interesting points are:
#SpringBootTest(webEnvironment = WebEnvironment.RANDOM_PORT)
For the bellow there is no need for further configuration in application.properties for example. It works as is:
#Value(value="${local.server.port}")
private int port;
Then you autowire the testRestTemplate and include the baseUrl in the call to your endpoint.