Support qualifiers to @MockBean

[willianconsta]

I'm trying to mock a RestTemplate annotated with LoadBalanced using @MockBean and got:

Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [org.springframework.web.client.RestTemplate] found for dependency [org.springframework.web.client.RestTemplate]: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true), @org.springframework.cloud.client.loadbalancer.LoadBalanced()}
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.raiseNoMatchingBeanFound(DefaultListableBeanFactory.java:1406)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1057)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1019)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:566)
    ... 43 more

But found no way to give to the mock the @LoadBalanced qualifier.
Can we have qualifiers support to @MockBean?

[snicoll]

That doesn't feel right. You shouldn't care about load balancing on a mock. Are you injecting that RestTemplate somewhere with the qualifier maybe? A bit more info about your project is required to better understand the problem.

[wilkinsona]

I think I understand the problem. This test will fail:

package org.springframework.boot.test.mock.mockito;

import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;

import org.junit.Test;
import org.junit.runner.RunWith;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.test.context.junit4.SpringRunner;

import static org.mockito.Mockito.verify;

@RunWith(SpringRunner.class)
public class MockBeanForExistingBeanWithQualifierIntegrationTests {

    @MockBean
    private ExampleService service;

    @Autowired
    private MyController controller;

    @Test
    public void testMocking() throws Exception {
        this.controller.foo();
        verify(this.service).doSomething();
    }

    @Qualifier
    @Retention(RetentionPolicy.RUNTIME)
    @interface MyQualifier {

    }

    @Configuration
    static class TestConfig {

        @Bean
        public ExampleService service() {
            return new StandardExampleService();
        }

        @Bean
        public MyController controller(@MyQualifier ExampleService service) {
            return new MyController(service);
        }

    }

    interface ExampleService {

        void doSomething();

    }

    @MyQualifier
    static class StandardExampleService implements ExampleService {

        @Override
        public void doSomething() {

        }

    }

    static class MyController {

        private final ExampleService service;

        public MyController(ExampleService service) {
            this.service = service;
        }

        public void foo() {
            this.service.doSomething();
        }

    }

}

The problem is that the ExampleService mock doesn't have the MyQualifier qualifier so the injection into the controller bean method fails.

[willianconsta]

Sorry being unclear, but @wilkinsona got the idea.
The problem I faced is exactly what he showed.

[snicoll]

OK I am working on this one and it's a bit harder than I thought. Several things:

• @MockBean can be specified on @Configuration classes so in that case we'll have no way to qualify the change
• There is no SPI or utility to collect the qualifier values from the injection point so I'll have to duplicate that logic in boot
• If several beans of the same type are present (that's usually why you use qualifiers in the first place), we need to identify which instance matches the qualifier specified on the injection point. Fortunately, there seem to be an API for that

It's quite a large change but I want to give that a go and then we can decide if we can afford to add that to 1.4.1.

[snicoll]

This requires a change in Spring Framework, I am tackling that in SPR-14725