Java9多模块Maven项目测试依赖项

Question

I have a multi-module maven project with three modules core , utils and test-utils

Core has the following dependencies definition

<dependency>
   <groupId>my.project</groupId>
   <artifactId>utils</artifactId>
</dependency>
<dependency>
   <groupId>my.project</groupId>
   <artifactId>test-utils</artifactId>
   <scope>test</scope>
</dependency>

I have added Java 9 module-info.java definitions for all three modules and core 's looks like this:

module my.project.core {
   requires my.project.utils;
}

However I cannot figure out how to get core 's test classes to be able to see the test-utils classes during test execution. When maven-surefire-plugin attempts the test run I get class not found.

If I add a requires my.project.testutils; to core 's module-info.java :

module my.project.core {
   requires my.project.utils;
   requires my.project.testutils; //test dependency
}

Then at compile time I get an error that the my.project.testutils module can't be found (presumably because it's only brought in as a test dependency).

How does one work with test dependencies in a Java 9 modular world? For obvious reason's I don't want my main code to pull in test dependencies. Am I missing something?

Answer 1

With maven and java9, if your my.project.testutils is a test scope dependency, you don't need to explicitly include( requires ) it in the module descriptor.

---

The test dependencies are taken care via the classpath itself. So you can simply remove the testutils and it would be patched by maven while executing tests.

module my.project.core {
   requires my.project.utils;
}

Refer to the slide 30 pertaining to maven-compiler-plugin.

I would also suggest you take a look at Where should I put unit tests when migrating a Java 8 project to Jigsaw and this comment by Robert confirming on the implementation that maven follows.

Edit : Created a sample project drawing an analogy that the main module is same as your core , the dependency on guava is same as your utils and the junit dependency is same as your testutils .