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

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

What's the stack trace of the NPE and why have you commented out the `@Value` annotation on the `port` field? — Andy Wilkinson, Aug 09 '16 at 19:55
Hi Wilkinson, I have attached the stacktrace of the Issue and While testing I tried by keeping port value as is and by commenting out while pasting in stackoverflow forgot to remove it. So it can be ignored . Attached error is when I didn't commented my @Value on the port field — rajadilipkolli, Aug 09 '16 at 20:05
could you please post your Application.java, just in case there is something unexpected in it, like ".web(false);" — alexbt, Aug 09 '16 at 23:55

score 16 · Accepted Answer · edited Feb 14 '17 at 18:54

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));       
    }
}

So basically you removed @WebAppConfiguration? I tried, it works! — alexbt, Aug 10 '16 at 00:59
I also updated the TestRestTemplate to be autowired and removed it's base_url setup. That stuff is automatically dealt with for you so you can clean up the test to not care about the host:port and instead just use relative URL's on the template. — Shawn Clark, Aug 10 '16 at 01:07

score 0 · Answer 2 · answered Jan 05 '23 at 12:53

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.

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

2 Answers2