Resolving Maven circular dependencies between test, testhelper, and project-under-test

Question

my set up is this. I have project A, and a test project depending on A:

A <- A_t

I also have other projects depending on A (and their tests):

A <- B <- B_t

To simplify some of the testing I introduce a new library helping test stuff based on A:

A <- Atesthelper

So A_t (and B_t) will depend on this test helper, like this:

A <- A_t
^    |
|    v
Atesthelper

However when I create Maven projects (pom.xml) it seems the usual thing is to bundle both the project and the test of that project in the same pom.xml. And I create a new pom.xml for the Atesthelper

So now it becomes:

(A <- A_t)
  ^    |
  |    v
Atesthelper

Which is a circular dependency. Is it possible in the pom.xml to somehow specify that Atesthelper is only a dependency of the test build target, and not the A module in itself?

So the build order should be: A, Atesthelper, A_t. I.e. A and A_t which are specified in the same pom, should not be build at the same time.

Thanks in advance.

Answer 1

If I understand you right, your primary goal is to reuse test classes. A_t and Atesthelper are not Maven projects, they are tests.

Make Maven to create a jar from your src/test/java. See http://maven.apache.org/guides/mini/guide-attached-tests.html

After build of A you will get A.jar and A-tests.jar. A-tests.jar will include Atesthelper and A_t.

Set dependency of B to A-tests.jar (<type>test-jar</type>).

Answer 2

The problem that you need to solve is the dependency from Atesthelper to A, then everything else will work fine: A depends on Atesthelper, B depends on Atesthelper and both A and B will contain both sources and tests. Atesthelper will be included with scope test in both A and B. That's your target state.

How do you get there? You need to extract the items that Atesthelper is depending on into a separate projects. Typically, these are interfaces or other common functionality, which should be put into a separate project anyway - let's call it ACommon. So your target layout should look like this:

ACommon <- Atesthelper
       ^    ^
       |   /
         A (and also B)

What kind of functionality is Atesthelper depending on in A? Can you move it to a separate project (ACommon)?