Spring-testのJunitを使ったテストでNullPointExceptionが出る

Question

Spring-testを使ってControllerクラスのメソッドをテストしたのですが、Null Point Exceptionがでてしまい原因がわかりません。
実際は、getメソッドが呼び出されて遷移することができるのですが、Junitでテストを行うとエラーが出てしまいます。よろしくお願いします。

参考にしたサイト：https://qiita.com/ryo2132/items/ec10116238e1e1f333a1

対象のクラスなどは以下の通りです。

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.servlet.ModelAndView;

import com.example.demo.entity.KeyEntity;
import com.example.demo.repository.KeyRepository;

@Controller
@RequestMapping("/")

public class IndexController {
	@Autowired

	KeyRepository rep;

	@RequestMapping(value = "/index", method = RequestMethod.GET)
	public ModelAndView index(ModelAndView mav) {
		mav.setViewName("index");
		mav.addObject("msg", "一覧表示をします");
		Iterable<KeyEntity> list = rep.findAll();
		mav.addObject("data", list);
		return mav;
	}
}

package com.example.demo;

import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.*;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.*;

import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.autoconfigure.web.servlet.AutoConfigureMockMvc;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import org.springframework.test.web.servlet.MockMvc;
import org.springframework.test.web.servlet.setup.MockMvcBuilders;

import com.example.demo.controller.IndexController;

@RunWith(SpringJUnit4ClassRunner.class)
@SpringBootTest
@AutoConfigureMockMvc

public class IndexControllerTest {
	@Autowired
	private MockMvc mockMvc;
	IndexController index;

	@Before
	public void setup() {
		mockMvc = MockMvcBuilders.standaloneSetup(index).build();
	}

	@Test
	public void getIndexTest() throws Exception {
	    // when
	    mockMvc.perform(get("/index"))
	         .andExpect(status().isOk())
	         .andExpect(view().name("index"))
	         .andExpect(model().attribute("msg", "一覧表示をします"));
	  }



}

java.lang.NullPointerException
	at org.springframework.test.web.servlet.setup.StubWebApplicationContext.addBeans(StubWebApplicationContext.java:149)
	at org.springframework.test.web.servlet.setup.StandaloneMockMvcBuilder.registerMvcSingletons(StandaloneMockMvcBuilder.java:380)
	at org.springframework.test.web.servlet.setup.StandaloneMockMvcBuilder.initWebAppContext(StandaloneMockMvcBuilder.java:370)
	at org.springframework.test.web.servlet.setup.AbstractMockMvcBuilder.build(AbstractMockMvcBuilder.java:140)
	at com.example.demo.IndexControllerTest.setup(IndexControllerTest.java:29)
	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:498)
	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.RunBefores.evaluate(RunBefores.java:24)
	at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:75)
	at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:86)
	at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:84)
	at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:251)
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:97)
	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:190)
	at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:89)
	at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:41)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:541)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:763)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:463)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:209)

Answer 1

IndexControllerの部分で、
@Autowired
private MockMvc mockMvc;
@Autowired
IndexController index;
に、setViewNameをvalueに書かれているものと変えたのちにTestClassの該当部分を変更したら無事エラーが解消されました！