Is there a way to overide automatically injected beans in Spring boot when writing tests? - spring-boot

Question

I have a class annotated with a spring bean #Repository("clientDatasource") called ClientServiceDatasource which implements an interface called Datasource. I also have a mock implementation of this interface also annotated with a spring bean #Repository("mockDatasource") called MockClientServiceDatasource. I also have a class annotated with the spring bean #Service called ClientService and in in its constructor, I pass in a datasource. I do it like so:
#Service
class ClientService (#Qualifier("clientDatasource") private val dataSource: Datasource){}
As you can see that the service will default to the clientDatasource, because of the #Qualifier when the application is running.
However when I run my tests I annotate my test class with #SpringTest . In my understanding this means that it boots up the entire application as if it were normal. So I want to somehow overide that #Qualifier bean thats being used in the client service in my test so that the Client Service would then use the mockedDatasource class.
I'm fairly new to kotlin and spring. So I looked around and found ways to write a testConfig class to configure beans like so :
#TestConfiguration
class TestConfig {
#Bean
#Qualifier("clientDatasource")
fun mockDatasource(): Datasource {
return MockClientServiceDatasource()
}
}
and then using it in the test like so:
#SpringTest
#Import(TestConfig::class)
class ClientServiceTest {
...
}
I also asked chatGPT and it gave me this:
#SpringBootTest
class ClientServiceTest {
#Autowired
lateinit var context: ApplicationContext
#Test
fun testWithMockedDatasource() {
// Override the clientDatasource bean definition with the mockDatasource bean
val mockDatasource = context.getBean("mockDatasource", Datasource::class.java)
val mockClientDatasourceDefinition = BeanDefinitionBuilder.genericBeanDefinition(MockClientServiceDatasource::class.java)
.addConstructorArgValue(mockDatasource)
.beanDefinition
context.registerBeanDefinition("clientDatasource", mockClientDatasourceDefinition)
// Now the ClientService should use the mockDatasource when it's constructed
val clientService = context.getBean(ClientService::class.java)
// ... do assertions and other test logic here ...
}
}
But some of the methods don't work, I guess chatGPT knowledge is outdated.
I also looked through spring docs, but couldn't find anything useful.

Answer 1

Okay, So I took a look at the code previously with the TestConfig class. And I realised by adding the:
#Primary
annotation to the method inside my TestConfig class, it basically forces that to be the primary repository bean. Like so:
#TestConfiguration
class TestConfiguration {
#Bean
#Primary
#Qualifier("clientDatasource")
fun mockDatasource(): Datasource {
return MockClientDataSource()
}
}
and in the test I only imported the test and it just worked. I didn't have to autowire anything
This is my test class:
#SpringBootTest
#AutoConfigureMockMvc
#Import(TestConfiguration::class)
internal class ServiceControllerTest{
#Suppress("SpringJavaInjectionPointsAutowiringInspection")
#Autowired
lateinit var mockMvc: MockMvc
#Test
fun `should return all clients` () {
// when/then
mockMvc.get("/clients")
.andDo { print() }
.andExpect {
status { isOk() }
content { contentType(MediaType.APPLICATION_JSON) }
jsonPath("$[0].first_name") {value("John")}
}
}
}