jar-with-dependencies and a managed dependency

We have a parent project with about dozen child projects. Most of the child projects have tests, and so they depend on JUnit. I thought it would make sense to pull this out to the parent pom as a managed dependency:

<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
            <scope>test</scope>
        </dependency>
    </dependencies>
</dependencyManagement>

In one of my child projects - still working on cleaning up this one - I need JUnit during build. So in that pom I now have:

    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <scope>compile</scope>
    </dependency>

This works fine. The part where things fall apart, is that this project also needs to be built as a jar with dependencies, using:

        <plugin>
            <artifactId>maven-assembly-plugin</artifactId>
            <executions>
                <execution>
                    <phase>package</phase>
                    <goals>
                        <goal>single</goal>
                    </goals>
                </execution>
            </executions>
            <configuration>
                <descriptorRefs>
                    <descriptorRef>jar-with-dependencies</descriptorRef>
                </descriptorRefs>
                <finalName>TestIntegration</finalName>
            </configuration>
        </plugin>

The jar-with-dependencies is missing JUnit. Note that if I remove JUnit as a managed dependency, and specify it as a normal dependency in that project, then everything builds fine.

How do I get jar, as a managed dependency scoped for test, into a jar-with-dependencies?

Managed dependency is used to lock the version at the parent pom. It does not mean that junit will automatically be a dependency of child projects.

You need to specify it as a dependency in the child or in parent pom for it to be included in a uber jar

Update: I misunderstood the question and thought that the OP was asking about using a dependency declared in dependency mgmt only.

How do I get jar, as a managed dependency scoped for test, into a jar-with-dependencies?

Dependency management takes precedence over dependencies declared in dependency section - so redefining the dependency in dependencies with scope compile will not work. To fix this, redefine the dependency in the child pom's dependency management section.

So your parent pom has:

<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.11</version>
            <scope>test</scope>
        </dependency>
    </dependencies>
</dependencyManagement>

Add this to your child pom:

<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.11</version>
            <scope>compile</scope>
        </dependency>
    </dependencies>
</dependencyManagement>