在多模块Maven项目中临时解决依赖项

Question

I have an multi-module project in maven, and when I run normal goals on it, everything works fine. For testing, I have an module mytest, and this module is run fine when I run mvn package in the parent directory.

But for not compiling and running everything everytime, I would prefer to run the tests standalone, and to take the packaged files as the dependencies. But if I try to do so using mvn test -Dtest=simpleTest in the test-submodule-directory, the tests are not run, because it can't find the dependencies. After a mvn install in the parent-directory, it finds them, but uses the artifacts from the repository - a behaviour I do not want, because I have to run install everytime. And if I try to run the tests from the parent directory with mvn test -Dtest=simpleTest, it does not find the tests in the other modules, and stops, or, if I add an project-list with -pl test, it just does not find the dependencies again.

Is there any way to run a maven test in a specific submodule, that has dependencies for other submodules, without installing the submodules to the local repository? It would be possible to archieve this by building the comand-line-call for the test onself, but that seems very time-consuming.

/EDIT:

To describe the problem more exactly, I'll add source of a minimal project.

There is a parent pom:

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>minimalproject</groupId>
    <artifactId>minimalproject</artifactId>
    <version>0.1-SNAPSHOT</version>
    <packaging>pom</packaging>

    <name>minimalproject</name>

    <modules>
        <module>datamodule</module>
        <module>testmodule</module>
    </modules>
</project>

a Pom for the module that needs to be tested (in a real-world project, there would be more similiar modules):

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>minimalproject</groupId>
    <artifactId>datamodule</artifactId>
    <version>0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>datamodule</name>
</project>

and a Pom for the modules that tests:

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>minimalproject</groupId>
    <artifactId>testmodule</artifactId>
    <version>0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>testmodule</name>

    <dependencies>
        <dependency>
            <groupId>minimalproject</groupId>
            <artifactId>datamodule</artifactId>
            <version>0.1-SNAPSHOT</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit-dep</artifactId>
            <version>4.8.2</version>
            <scope>test</scope>
        </dependency>
    </dependencies>
</project>

There are now two classes, one in datamodule/src/main/java:

public class Thing{
    int i = 5;
}

and one in testmodule/src/test/java:

import org.junit.Test;
import junit.framework.Assert;

public class MyTest{

    @Test
    public void testThing(){
        Thing t = new Thing();
        Assert.assertEquals(5, t.i);
    }
}

When I now run mvn package in the parent folder, everything works fine. But if I run mvn test in the testmodule folder, it crashes because it can't resolve the dependency to the datamodule. If I run mvn install in the parent folder before, it works - but takes the old installed version.

What I want is the ability to run the integration-test in the testmodule, without calling other tests or invoking the build-process of other parts. Is there any possibility to do so?

/EDIT2:

I found out when googling the issue, that one could have done that in maven 2 with the reactor plugin: Build single module from multimodule pom . Anyways, this plugin is not used anymore ( http://maven.40175.n5.nabble.com/VOTE-Retire-Maven-Reactor-Plugin-td5789172.html ). In fact, like proposed in the first answer, people say one could use profiles to do this: How do you perform a reactor build in Maven3 without a root project?

But, when adding a profile like this:

<profiles>
    <profile>
        <id>onlyRunTests</id>
        <modules>
            <module>testmodule</module>
        </modules>
    </profile>
</profiles>

And runnning it with mvn test -P onlyRunTests, still everything which comes before testing the testmodule (so compiling and running the datamodule) is executed. Unfortunately, this is the behaviour not wanted - I want to call integration tests, not the unit tests from the other modules. So is there any way to do so?

/EDIT 3: There were two other promising ways to avoid this Problem: building with --pl eg --pl testmodule --also-make-dependencies. This does not work either, it does not build the dependencies. The other way would be defining a path (with systemPath) of the depencies. This does not work, as it only works with absolute paths, and this would make the pom unexecutable under all other systems.

Answer 1

The problem in your build is (based on the example pom files) not a multi-module build cause if you have a multi-module build all your childs need to have a parent which is not the case. In your case you are having an aggregator which is not what you need.

The test module should look like this:

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <parent>
      <groupId>minimalproject</groupId>
      <artifactId>minimalproject</artifactId>
      <version>0.1-SNAPSHOT</version>
    </parent>

    <artifactId>testmodule</artifactId>

    <name>testmodule</name>

    <dependencies>
        <dependency>
            <groupId>minimalproject</groupId>
            <artifactId>datamodule</artifactId>
            <version>${project.version}</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit-dep</artifactId>
            <version>4.8.2</version>
            <scope>test</scope>
        </dependency>
    </dependencies>
</project>

and your datamodule should look like this:

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <parent>
      <groupId>minimalproject</groupId>
      <artifactId>minimalproject</artifactId>
      <version>0.1-SNAPSHOT</version>
    </parent>

    <artifactId>datamodule</artifactId>

    <name>datamodule</name>
</project>

Now if you look at the root and try mvn clean package you should see that the testmodule is build after the datamodule. This is needed as you already determined to let Maven calculate the build order of the artifacts.