[FIXED] Spring tests - use real bean to create test bean

Issue

I use Spring, and created a test which loads the context using SpringRunner.

I have a bean which looks like this:

@Bean
public Properties kafkaStreamsProperties(){
    final Properties props = new Properties();
    props.put("A", "B");
    props.put("C", "D");

    return props;
}

I would like to extend it in my testing to also contain a property "E" --> "F".

I can easily do it in an inner @TestConfiguration class as follows:

public class test{
    public static class MyConfig{
        @Bean
        public Properties kafkaStreamsProperties(){
            final Properties props = new Properties();
            props.put("A", "B");
            props.put("C", "D");
            props.put("E", "F");
            return props;
        }
    }
}

But then when I change the production code, I'll have to "remember" changing the test too. Is there any way I can get the actual bean from the context and "replace" it with mine (using the actual one)?

Solution

In Spring Test you have @MockBean to mock a bean or @SpyBean to Spy a bean:

Spring Boot includes a @MockBean annotation that can be used to define a Mockito mock for a bean inside your ApplicationContext. You can use the annotation to add new beans or replace a single existing bean definition.

Additionally, you can use @SpyBean to wrap any existing bean with a Mockito spy

Answered By - user7294900