单元测试存储库spring org.springframework.beans.factory.UnsatisfiedDependencyException

Question

2. I'm using Spring Boot and MongoDB to create a simple school application. I want to test the methods that are defined in the service class but I get the following exception:

    org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name'com.backintime.BackInTimeSpring.Service.TeacherServiceTest': Unsatisfied dependency expressed through field 'teacherService'; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'com.backintime.BackInTimeSpring.Service.TeacherService' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)} 

3. My classes are the following:

4. Repository:

    package com.backintime.BackInTimeSpring.Model.Repository; @Component @Repository public interface ITeacherRepository extends MongoRepository<Teacher,String> { @Query("{}") Stream<Teacher> findAllTeachers(); List<Teacher> findByLastNameIgnoreCase(String lastName); List<Teacher> findByFirstNameIgnoreCase(String firstName); } 

5. Service:

    package com.backintime.BackInTimeSpring.Service; @Component @Service public class TeacherService { @Autowired private ITeacherRepository teacherRepository; public List<Teacher> retrieveAllTeachers(){ return this.teacherRepository.findAllTeachers().sorted(Comparator.comparing(Teacher::getLastName)).collect(Collectors.toList()); } public Teacher retrieveTeachersById(String id) { return this.teacherRepository.findAllTeachers().filter(t -> t.getId().equals(id)).findFirst().get(); } public List<Teacher> retrieveTeachersByLastName(String lastName){ return this.teacherRepository.findByLastNameIgnoreCase(lastName); } public List<Teacher> retrieveTeachersByFirstName(String firstName){ return this.teacherRepository.findByFirstNameIgnoreCase(firstName); } public void saveTeacher(Teacher t){ this.teacherRepository.save(t); } public String greet() { return "Hello World"; } 

   }

6. Unittest:

    package com.backintime.BackInTimeSpring.Service; @RunWith(SpringRunner.class) @ComponentScan(basePackages = "com.backintime.BackInTimeSpring") public class TeacherServiceTest { @Autowired TeacherService teacherService; @Test public void retrieveAllTeachers() { assertEquals(3, teacherService.retrieveAllTeachers().size()); } 

Answer 1

This is happening due to the fact that you are using @ComponentScan in the wrong place.

Usually it is used in your Main Application class or in configuration classes not where you define the beans.

Please refer to this link: https://springframework.guru/spring-component-scan/

There is a similar question in here, and as you can see they are as well using @ComponentScan in the Main application

How to use @ComponentScan together with test-specific ContextConfigurations in SpringJunit4TestRunner?