java.lang.IllegalStateException: Failed to load ApplicationContext

这是没有加载配置文件导致的异常，解决办法如下：

如果你的配置文件是.xml格式，就加上@ContextConfiguration

import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringRunner;

@SpringBootTest
@RunWith(SpringRunner.class)
@ContextConfiguration(locations = {"classpath:application.xml"})
public class JunitTest {
    @Test
    public void test(){
        System.out.println("测试");
    }
}

如果你的配置文件是.properties格式，就加上@TestPropertySource

import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.TestPropertySource;
import org.springframework.test.context.junit4.SpringRunner;

@SpringBootTest
@RunWith(SpringRunner.class)
@TestPropertySource(locations = {"classpath:application.properties"})
public class JunitTest {
    @Test
    public void test(){
        System.out.println("测试");
    }
}