To illustrate the issue I have two separate @SpringBootTest classes each of which have an inner @TestConfiguration static class both of which create the same bean.

When I run TestB I see that the "stringBeans" bean from TestA is being created and used and vice versa. Why is this? I want to be able to create different tests that define the same bean but with that bean configured differently. How can I achieve this?

@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT, properties = "spring.main.allow-bean-definition-overriding=true")
public class TestA {

    @TestConfiguration
    static class TestConfig {
        @Bean
        @Primary
        public String stringBeans() {
            System.out.println("Creating string bean from Test A");
            return "Test A";
        }
    }

    @Test
    public void testA() {
        System.out.println("Running Test A");
    }
}

When running the above test I see the following output:

Creating string bean from Test B

Running Test A

@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT, properties = "spring.main.allow-bean-definition-overriding=true")
public class TestB {

    @Autowired
    String stringBeans;

    @TestConfiguration
    static class TestConfig {
        @Bean
        @Primary
        public String stringBeans() {
            System.out.println("Creating string bean from Test B");
            return "Test B";
        }
    }

    @Test
    public void testB() {
        System.out.println("Running Test B");
        assertThat(stringBeans).isEqualTo("Test B");
    }
}

When running the above test the assert fails and I see the following output:

Creating string bean from Test A

Running Test B

I have tried creating separate classes annotated with @TestConfiguration and using @Import to pull them into each respective test but that does not resolve this issue consistently.