maven error - package org.junit does not exist

I got a little trouble using maven and junit. Running junit test on its own works perfect, but building with Maven mvn clean test fails. I made sure that all tests are within "src/test/java" and all sources are within "src/main/java", so junit can find them (regarding to other questions this was the problem in many other cases).

So does anybody knows why I this is not working for me?

Error Message snipped:

/D:/pathToProject/myProject/src/test/java/myPackage/MyFile.java:[5,17] package org.junit does not exist

Pom.xml Snipped:

<...project information.../>
  <build>
        <sourceDirectory>src</sourceDirectory>
        <plugins>
            <plugin>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.1</version>
                <configuration>
                    <source />
                    <target />
                </configuration>
            </plugin>
        </plugins>
    <plugins>
    </plugins>
  </build>
    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.11</version>
            <scope>test</scope>
        </dependency>
    </dependencies>
</project>