Getting I/O error while executing JUnit test case for Spring Controller - spring

Question

I am executing a test case to call spring controller (GET method). However, It throws below I/O error.
org.springframework.web.client.ResourceAccessException: I/O error on GET request for "http://localhost:8039": Connect to localhost:8039 [localhost/127.0.0.1, localhost/0:0:0:0:0:0:0:1] failed: Connection refused: connect; nested exception is org.apache.http.conn.HttpHostConnectException: Connect to localhost:8039 [localhost/127.0.0.1, localhost/0:0:0:0:0:0:0:1] failed: Connection refused: connect
at org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:674)
at org.springframework.web.client.RestTemplate.execute(RestTemplate.java:636)
Caused by: java.net.ConnectException: Connection refused: connect
at java.net.DualStackPlainSocketImpl.connect0(Native Method)
at java.net.DualStackPlainSocketImpl.socketConnect(DualStackPlainSocketImpl.java:79)
Below is the test case class that i am executing which throws the above error.
public class GetRuleSetsTests extends PreferencesAdminClientTestApplicationTests<GetRuleSetsResponse>{
#Test
public void testSuccess() throws Exception
{
final String mockedResponseJson = rawJsonFromFile("com/cnanational/preferences/client/rule-sets/getRuleSetsResponse.json");
MockRestServiceServer mockServer = mockServer();
mockServer.expect(requestTo(dummyUri()))
.andExpect(method(HttpMethod.GET))
.andExpect(queryParam("ruleSetDescription", "TestRuleDescription"))
.andRespond(withSuccess(
mockedResponseJson,
MediaType.APPLICATION_JSON));
ServiceClientResponse<GetRuleSetsResponse> response = executeDummyRequest();
mockServer.verify();
assertThat(response.isSuccessful(), equalTo(true));
GetRuleSetsResponse programResponse = response.getParsedResponseObject();
assertThat(programResponse.getRuleSets().size(), equalTo(2));
}
#Override
public URI dummyUri() {
return UriComponentsBuilder.fromUri(baseUri())
.path(this.endpointProperties.getRuleSets())
.build()
.toUri();
}
}
What am i missing? Any inputs appreciated.

Answer 1

If you have configured your test environment properly to run MockRestServiceServer
(by that, I mean #RunWith(SpringRunner.class) and #RestClientTest(ClassUnderTestThatCallsTheMockServer.class)), make sure that you are not instantiating your mock server with = new MockServer(), instead just use an instance that is #Autowired from the spring context (because that instance is configured out of the box).
I see that you have a lot of inheritance and overridden methods in your tests, calling things with this.returnSomething..., so make sure that you are not instantiating things outside of the spring context.
Here is a simple example of a mock server to get some posts:
#RunWith(SpringRunner.class)
#RestClientTest(PostClient.class)
public class PostClientMockTest {
// class under test
#Autowired
private PostClient postClient;
// autowired mock server from the spring context
#Autowired
private MockRestServiceServer mockRestServiceServer;
#Test
public void readPosts() throws Exception {
String mockJsonResponse = "My response";
mockRestServiceServer.expect(requestTo("https://myurl.com/posts?userId=1"))
.andRespond(withSuccess(mockJsonResponse, MediaType.APPLICATION_JSON_UTF8));
List<Post> posts = postClient.readPosts(1);
assertEquals(9, posts.size());
mockRestServiceServer.verify();
}
}
Hope this helps