Creating Testcontainer from custom image doesn't work

I'm writing tests for my room-service and i need the image-service because the room-service has dependencies on the image-service. this is my file tree:

+---image-service
¦   ¦   Dockerfile
¦   ¦   pom.xml
¦   ¦
¦   +---src
¦   ¦   +---main
¦   ¦   ¦   +---java
¦   ¦   ¦   +---resources
¦   ¦   +---test
¦   ¦       +---java
¦   ¦           +---de
¦   ¦               +---fh
¦   ¦                       ApplicationTest.java
+---room-service
¦   ¦   Dockerfile
¦   ¦   pom.xml
¦   ¦
¦   +---src
¦   ¦   +---main
¦   ¦   ¦   +---java
¦   ¦   ¦   +---resources
¦   ¦   +---test
¦   ¦       +---java
¦   ¦       ¦   +---de.fh
¦   ¦       ¦           ApplicationTest.java
¦   ¦       ¦
¦   ¦       +---resources
¦   ¦               application.yml

In my ApplicationTest in room-service I try to create a generic container from the dockerfile in /image-service/Dockerfile:

@BeforeClass
public static void init() {
    eurekaContainer = new GenericContainer(new ImageFromDockerfile("image-service")
            .withFileFromFile("./image-service", new File("../image-service/Dockerfile")));

    eurekaContainer.start();
}

I couldn't find any use cases like this in the documentation.
Am I using the wrong method? Are any of the paths I used wrong?

Start with room-service/src/test/java/.../ApplicationTest.java and the referenced image-service/Dockerfile. Check how ImageFromDockerfile and withFileFromFile resolve paths and run the room-service test; done means the custom image builds and the container starts successfully.