@Autowired Bean 在 Spring Boot 单元测试中为 NULL

Question

I am new to JUnit and automated testing and really want to get into automating my tests. This is a Spring Boot application. I have used Java Based Annotation style instead of XML based configuration.

I have a test class in which I'd like to test a method which retrieves a response based on a users' input.

Testing class:

@RunWith(SpringRunner.class)
@SpringBootTest
public class SampleTest(){

  @Autowired
  private SampleClass sampleClass;

  @Test
  public void testInput(){

  String sampleInput = "hi";

  String actualResponse = sampleClass.retrieveResponse(sampleInput);

  assertEquals("You typed hi", actualResponse);

  }
}

Inside my "SampleClass" I have autowired a bean like this.

@Autowired
private OtherSampleClass sampleBean;

Inside my "OtherSampleClass" I have annotated a method like so:

@Bean(name = "sampleBean")
public void someMethod(){
....
}

The issue I'm having is when I try to run the test without the @RunWith and @SpringBootTest annotations when I try to run the test my variables annotated @Autowired are null. And when I try to run the test with those annotations RunWith & SpringBootTest then I get an

IllegalStateException caused by BeanCreationException: Error creating bean with name "sampleBean" AND failure to load application context caused by BeanInstantiationException.

The code works 'properly' when I try to use it as a user would so I can always test this way but I think automated tests would be good for the longevity of the program.

I have used the Spring Boot Testing Docs to assist me in this.

Answer 1

The following config works for me.

File: build.gradle

testCompile("junit:junit:4.12")
testCompile("org.springframework.boot:spring-boot-starter-test")

File: MYServiceTest.java

import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.ActiveProfiles;
import org.springframework.test.context.junit4.SpringRunner;

@SpringBootTest(classes = Application.class,
    webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
@ActiveProfiles("test")
@RunWith(SpringRunner.class)
public class MYServiceTest {

    @Autowired
    private MYService myService;

    @Test
    public void test_method() {
        myService.run();
    }
}

Answer 2

It's best to keep Spring out of your unit tests as much as possible. Instead of Autowiring your bean just create them as a regular object

OtherSampleClass otherSampleClass = mock(OtherSampleClass.class);
SampleClass sampleClass = new SampleClass(otherSampleClass);

But for this you need to use the Constructor injection instead of Field Injection which improves testability.

Replace this

@Autowired
private OtherSampleClass sampleBean;

With this

private OtherSampleClass sampleBean;

@Autowired
public SampleClass(OtherSampleClass sampleBean){
    this.sampleBean = sampleBean;
}

Take a look at this answer for an other code example

Answer 3

No need to inject ( @Autowired private SampleClass sampleClass; ) your actual class which you are testing, and remove SpringBootTest annotation,
SpringBootTest annotation used for integration test cases.
find the following code will help you.

@RunWith(SpringRunner.class)
public class SampleTest(){

  private SampleClass sampleClass;