Dropwizard test - javax.validation.ConstraintViolationException: The request entity was empty - rest

Question

I am writing integration tests for REST services with Dropwizard 0.7. I am following Dropwizard documentation http://dropwizard.readthedocs.org/en/latest/manual/testing.html
I am trying test simple get request using io.dropwizard.testing library.
<dependency>
<groupId>io.dropwizard</groupId>
<artifactId>dropwizard-testing</artifactId>
<version>0.7.1</version>
</dependency>
My code is:
#ClassRule
public static final ResourceTestRule resources = ResourceTestRule.builder()
.addResource(new EvaluationResource())
.build();
#Test
public void testGetPrompt() {
List<Class<?>> mappedClasses = config();
HibernateUtil.init(ADeployer.DEPLOYMENT_DIR, "localhost", 3306, "stat", mappedClasses);
UserIdentity userIdentity = UserIdentityDAO.validate(new Long(1), "asdfasdf", "Slavina");
String token = UserIdentityDAO.generateToken(userIdentity);
User user = userManager.getUser(token);
resources.builder().setMapper(MAPPER);
resources.client().resource("https://localhost:8080/execute/prompt?sessionKey=" + token).type(MediaType.APPLICATION_JSON).get(User.class);
}
My method is:
#GET
#Path("/prompt")
public String getPromptMessage(#SessionAuth User user) {
try {
Autosave status = user.getWorker().getStatus(user.getSessionKey());
return status.getPendingPromptMessage();
}
catch (Exception e) {
throw new RestException(e);
}
}
What I get is successfully connected to db, I got the right token and Exception is:
Test c.s.j.s.c.ContainerResponse:419 [main] - The RuntimeException could not be mapped to a response, re-throwing to the HTTP container
javax.validation.ConstraintViolationException: The request entity was empty
at io.dropwizard.jersey.jackson.JacksonMessageBodyProvider.validate(JacksonMessageBodyProvider.java:70) ~[dropwizard-jersey-0.7.0.jar:0.7.0]
at io.dropwizard.jersey.jackson.JacksonMessageBodyProvider.readFrom(JacksonMessageBodyProvider.java:60) ~[dropwizard-jersey-0.7.0.jar:0.7.0]
at com.sun.jersey.spi.container.ContainerRequest.getEntity(ContainerRequest.java:490) ~[jersey-server-1.18.1.jar:1.18.1]
at com.sun.jersey.server.impl.model.method.dispatch.EntityParamDispatchProvider$EntityInjectable.getValue(EntityParamDispatchProvider.java:123) ~[jersey-server-1.18.1.jar:1.18.1]
at com.sun.jersey.server.impl.inject.InjectableValuesProvider.getInjectableValues(InjectableValuesProvider.java:86) ~[jersey-server-1.18.1.jar:1.18.1]
at com.sun.jersey.server.impl.model.method.dispatch.AbstractResourceMethodDispatchProvider$EntityParamInInvoker.getParams(AbstractResourceMethodDispatchProvider.java:153) ~[jersey-server-1.18.1.jar:1.18.1]
at com.sun.jersey.server.impl.model.method.dispatch.AbstractResourceMethodDispatchProvider$TypeOutInvoker._dispatch(AbstractResourceMethodDispatchProvider.java:183) ~[jersey-server-1.18.1.jar:1.18.1]
at com.sun.jersey.server.impl.model.method.dispatch.ResourceJavaMethodDispatcher.dispatch(ResourceJavaMethodDispatcher.java:75) ~[jersey-server-1.18.1.jar:1.18.1]
at io.dropwizard.jersey.guava.OptionalResourceMethodDispatchAdapter$OptionalRequestDispatcher.dispatch(OptionalResourceMethodDispatchAdapter.java:37) ~[dropwizard-jersey-0.7.0.jar:0.7.0]
at com.sun.jersey.server.impl.uri.rules.HttpMethodRule.accept(HttpMethodRule.java:302) ~[jersey-server-1.18.1.jar:1.18.1]
at com.sun.jersey.server.impl.uri.rules.RightHandPathRule.accept(RightHandPathRule.java:147) ~[jersey-server-1.18.1.jar:1.18.1]
at com.sun.jersey.server.impl.uri.rules.ResourceObjectRule.accept(ResourceObjectRule.java:100) ~[jersey-server-1.18.1.jar:1.18.1]
at com.sun.jersey.server.impl.uri.rules.RightHandPathRule.accept(RightHandPathRule.java:147) ~[jersey-server-1.18.1.jar:1.18.1]
at com.sun.jersey.server.impl.uri.rules.RootResourceClassesRule.accept(RootResourceClassesRule.java:84) ~[jersey-server-1.18.1.jar:1.18.1]
at com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1542) [jersey-server-1.18.1.jar:1.18.1]
at com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1473) [jersey-server-1.18.1.jar:1.18.1]
at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1419) [jersey-server-1.18.1.jar:1.18.1]
at com.sun.jersey.test.framework.impl.container.inmemory.TestResourceClientHandler.handle(TestResourceClientHandler.java:119) [jersey-test-framework-inmemory-1.18.1.jar:1.18.1]
at com.sun.jersey.api.client.Client.handle(Client.java:652) [jersey-client-1.18.1.jar:1.18.1]
at com.sun.jersey.api.client.WebResource.handle(WebResource.java:682) [jersey-client-1.18.1.jar:1.18.1]
at com.sun.jersey.api.client.WebResource.access$200(WebResource.java:74) [jersey-client-1.18.1.jar:1.18.1]
at com.sun.jersey.api.client.WebResource$Builder.get(WebResource.java:509) [jersey-client-1.18.1.jar:1.18.1]
at com.zh.backend.resources.PackageResourceTest.testGetPerson(PackageResourceTest.java:122) [test-classes/:na]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.7.0_55]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) ~[na:1.7.0_55]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.7.0_55]
at java.lang.reflect.Method.invoke(Method.java:606) ~[na:1.7.0_55]
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:47) [junit-4.11.jar:na]
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12) [junit-4.11.jar:na]
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:44) [junit-4.11.jar:na]
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17) [junit-4.11.jar:na]
at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26) [junit-4.11.jar:na]
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:271) [junit-4.11.jar:na]
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:70) [junit-4.11.jar:na]
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50) [junit-4.11.jar:na]
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:238) [junit-4.11.jar:na]
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:63) [junit-4.11.jar:na]
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:236) [junit-4.11.jar:na]
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:53) [junit-4.11.jar:na]
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:229) [junit-4.11.jar:na]
at io.dropwizard.testing.junit.ResourceTestRule$1.evaluate(ResourceTestRule.java:150) [dropwizard-testing-0.7.1.jar:0.7.1]
at org.junit.rules.RunRules.evaluate(RunRules.java:20) [junit-4.11.jar:na]
at org.junit.runners.ParentRunner.run(ParentRunner.java:309) [junit-4.11.jar:na]
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50) [.cp/:na]
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38) [.cp/:na]
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459) [.cp/:na]
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:675) [.cp/:na]
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382) [.cp/:na]
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192) [.cp/:na]
For sure I am doing something wrong passing parameters, but I couldn't find out what, can you help me?

Answer 1

I had a lot of trouble with a problem very similar to this, and have just found the fix, which I'm hoping will help here also.
In my case the reason for the "ConstraintViolationException: The request entity was empty at " exception is because when the Resource mock is being constructed it runs through all of the annotations and compares them to a map of annotations it expects. None of these are #SessionAuth, or #Auth(which I was using), so by default it assumes that annotation must mean that its related parameter is the entity. In the case of a get request there isn't an entity, so it bombs out.
The solution appears to be to call .addProvider in your ResourceTestRule builder, so it can look for an understand the annotation. For example I had to do:
#Rule
public final ResourceTestRule resources = ResourceTestRule.builder()
.addResource(new GroupSuggestionsResourceV1(RANKING_STORE, CLIENT))
.addProvider(new OAuthProvider<>(AUTHENTICATOR, "test-realm"))
.build();
which told the resource builder to expect an auth annotation, and handle it appropriately. Initially I was just doing .addProvider(AUTHENTICATOR) but that didn't work, so if you have trouble you might want to try both.
I hope this helps other people with this problem!