How to unit test a webservice call with Junit4 and android-async-http?

I'm trying to unit test a webservice call but when i run the instrumental test it throws this exception:

java.lang.IllegalArgumentException: Synchronous ResponseHandler used in AsyncHttpClient. You should create your response handler in a looper thread or use SyncHttpClient instead.
at com.loopj.android.http.AsyncHttpClient.sendRequest(AsyncHttpClient.java:1493)
at com.loopj.android.http.AsyncHttpClient.post(AsyncHttpClient.java:1169)
at com.loopj.android.http.AsyncHttpClient.post(AsyncHttpClient.java:1152)
at com.mr_apps.androidbase.webservice.BaseLoopJSecurity.baseOperationWithPath(BaseLoopJSecurity.java:253)
at com.mr_apps.androidbase.webservice.BaseLoopJSecurity.baseOperationWithPath(BaseLoopJSecurity.java:204)
at com.mr_apps.smoll.webservice.WebServiceSecurity.secureOperationWithPath(WebServiceSecurity.java:39)
at com.mr_apps.smoll.webservice.ShopService.getConfigurations(ShopService.java:89)
at com.mr_apps.smoll.WebServiceTest.configurationCall(WebServiceTest.java:49)
at java.lang.reflect.Method.invoke(Native Method)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
at android.support.test.rule.ServiceTestRule$ServiceStatement.evaluate(ServiceTestRule.java:329)
at org.junit.rules.RunRules.evaluate(RunRules.java:20)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
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.junit.runners.ParentRunner.run(ParentRunner.java:363)
at org.junit.runners.Suite.runChild(Suite.java:128)
at org.junit.runners.Suite.runChild(Suite.java:27)
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$2.evaluate(ParentRunner.java:268)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
at org.junit.runner.JUnitCore.run(JUnitCore.java:115)
at android.support.test.internal.runner.TestExecutor.execute(TestExecutor.java:59)
at android.support.test.runner.AndroidJUnitRunner.onStart(AndroidJUnitRunner.java:262)
at android.app.Instrumentation$InstrumentationThread.run(Instrumentation.java:1879)

this is my testing class:

@RunWith(AndroidJUnit4.class)
@MediumTest
public class WebServiceTest {

    Context mMockContext;

    @Before
    public void setUp() {
        mMockContext = new RenamingDelegatingContext(InstrumentationRegistry.getTargetContext(), "test_");
    }

    @Test
    public void configurationCall() throws Exception{


        ShopService.getConfigurations(mMockContext, new FutureCallback() {
            @Override
            public void completed(Boolean result) {
                Assert.assertEquals(true, result.booleanValue());
            }

            @Override
            public void failed(Exception ex) {
                Assert.assertEquals(true, false);
            }

            @Override
            public void cancelled() {
                Assert.assertEquals(true, false);
            }
        });

    }


}

I know that i can switch to SyncHttpClient, but how can i unit test with AsyncHttpClient?