Testing with spring context mocking mongoBD

I'm trying to write some tests using Spring context + TestNG + Mockito + FEST

I have Controller which I want to test

@RestController
@RequestMapping("/admin/offers/v1")
public class OfferActionsController {

    private OfferService offerService;

    @Autowired
    public OfferActionsController(OfferService offerService) {
        this.offerService = offerService;
    }

    @RequestMapping(value = "/save", method = RequestMethod.POST)
    public ResponseEntity<Offer> save(@RequestBody Offer offer) {
        Offer offerSaved = offerService.save(offer);
        return new ResponseEntity<>(offerSaved, HttpStatus.OK);
    }

OfferService contains injected OfferRepository

import cobytu.offer.document.Offer;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.Pageable;
import org.springframework.data.mongodb.repository.MongoRepository;

import java.util.List;

public interface OfferRepository extends MongoRepository<Offer, String> {

}

So I'm using default save method.

I want to write some tests using spring context. What I need is to mock OfferRepository (MongoDB repository) as a bean and add it to spring context, next step is to use spring context for my test classes, i want this effect to create test envoirnment closest to normal app, where i can use @Autowire in test instead of @Mock

So my test class looks like this

import org.fest.assertions.Assertions;
import org.mockito.BDDMockito;
import org.mockito.MockitoAnnotations;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.ResponseEntity;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.support.AnnotationConfigContextLoader;
import org.springframework.test.context.testng.AbstractTestNGSpringContextTests;
import org.testng.annotations.BeforeMethod;
import org.testng.annotations.Test;

import static org.mockito.Matchers.any;

@Test
@ContextConfiguration(classes= TestEdge2EdgeConfiguration.class, loader=AnnotationConfigContextLoader.class)
public class OfferActionsControllerTest extends AbstractTestNGSpringContextTests {

    @Autowired
    private OfferRepository offerRepository;

    @Autowired
    private OfferActionsController offerActionsController;

    @BeforeMethod
    public void setUp(){
        MockitoAnnotations.initMocks(this);
    }

    @Test
    public void saveOffer() {
        //given
        BDDMockito.given(offerRepository.save(any(Offer.class))).willReturn(new Offer());
        //when
        ResponseEntity<Offer> save = offerActionsController.save(new Offer());

        //then
        Assertions.assertThat(save).isNotNull();
    }
}

Spring context for my tests

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.FilterType;

import static org.mockito.Mockito.mock;

@ComponentScan(basePackages = "myapp", excludeFilters =
@ComponentScan.Filter(type = FilterType.ASSIGNABLE_TYPE,
        value = {
                OfferService.class
        }
)
)
@Configuration
public class TestEdge2EdgeConfiguration {

    @Bean
    public OfferRepository offerRepository() {
       return mock(OfferRepository.class);
    }

}

First problem I have is that debugger dont enter to TestEdge2EdgeConfiguration offerRepository bean creation method.

Second problem is error from OfferActionsControllerTest section

//given
BDDMockito.given(offerRepository.save(any(Offer.class))).willReturn(new Offer());

Debugger dont enter to section //when and this is stack trace

java.lang.IllegalArgumentException: Entity must not be null!

    at org.springframework.util.Assert.notNull(Assert.java:115)
    at org.springframework.data.mongodb.repository.support.SimpleMongoRepository.save(SimpleMongoRepository.java:73)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:483)
    at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.executeMethodOn(RepositoryFactorySupport.java:483)
    at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.doInvoke(RepositoryFactorySupport.java:468)
    at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.invoke(RepositoryFactorySupport.java:440)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
    at org.springframework.data.projection.DefaultMethodInvokingMethodInterceptor.invoke(DefaultMethodInvokingMethodInterceptor.java:61)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
    at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:92)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
    at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:208)
    at com.sun.proxy.$Proxy57.save(Unknown Source)
    at cobytu.admin.offer.controller.OfferActionsControllerTest.saveOffer(OfferActionsControllerTest.java:37)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:483)
    at org.testng.internal.MethodInvocationHelper.invokeMethod(MethodInvocationHelper.java:86)
    at org.testng.internal.MethodInvocationHelper$1.runTestMethod(MethodInvocationHelper.java:197)
    at org.springframework.test.context.testng.AbstractTestNGSpringContextTests.run(AbstractTestNGSpringContextTests.java:175)
    at org.testng.internal.MethodInvocationHelper.invokeHookable(MethodInvocationHelper.java:209)
    at org.testng.internal.Invoker.invokeMethod(Invoker.java:639)
    at org.testng.internal.Invoker.invokeTestMethod(Invoker.java:820)
    at org.testng.internal.Invoker.invokeTestMethods(Invoker.java:1128)
    at org.testng.internal.TestMethodWorker.invokeTestMethods(TestMethodWorker.java:129)
    at org.testng.internal.TestMethodWorker.run(TestMethodWorker.java:112)
    at org.testng.TestRunner.privateRun(TestRunner.java:782)
    at org.testng.TestRunner.run(TestRunner.java:632)
    at org.testng.SuiteRunner.runTest(SuiteRunner.java:366)
    at org.testng.SuiteRunner.runSequentially(SuiteRunner.java:361)
    at org.testng.SuiteRunner.privateRun(SuiteRunner.java:319)
    at org.testng.SuiteRunner.run(SuiteRunner.java:268)
    at org.testng.SuiteRunnerWorker.runSuite(SuiteRunnerWorker.java:52)
    at org.testng.SuiteRunnerWorker.run(SuiteRunnerWorker.java:86)
    at org.testng.TestNG.runSuitesSequentially(TestNG.java:1244)
    at org.testng.TestNG.runSuitesLocally(TestNG.java:1169)
    at org.testng.TestNG.run(TestNG.java:1064)
    at org.testng.IDEARemoteTestNG.run(IDEARemoteTestNG.java:72)
    at org.testng.RemoteTestNGStarter.main(RemoteTestNGStarter.java:122)