Wrap @SetEnvironmentVariable in a JUnit Extension

We have a few JUnit test classes that need to bring up the Spring context, and due to some Kafka libraries, we need to set an environment variable in order for the context to successfully load. Would it be possible to wrap the annotation in a JUnit Extension so we only need to put the particular code for the environment variable setting in one place? That way we can just add our custom extension to @ExtendWith wherever it’s needed.

[Michael1993]

Okay, so, I tested it. It kind of works but not as I originally wrote. Here is what you need to do:

1. Create your extension:

public class MyKafkaExtension implements BeforeEachCallback {
    // extension logic here
}

1. Create a composed annotation:

@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
@ExtendWith(MyKafkaExtension.class)
@SetEnvironmentVariable(key = "foobar", value = "barfoo") // you reference SetEnvironmentVariable here!!!
public @interface KafkaExtension {
}

1. Use the composed annotation in your test classes:

@Test
@KafkaExtension
void testUsingKafkaEnvVar() {
  // Invokes both MyKafkaExtension and the EnvironmentVariableExtension
}

This is a bit unfortunate, because you have to use @ExtendWith indirectly, but (in my opinion) it also looks somewhat nicer?

@spartanhooah Let us know if this solution works for you.

[spartanhooah]

Thanks, that works great! I can use @beatngu13’s suggestion since I don’t have any other logic I need to inject.