When using maven.test.skip it should skip downloading plugins which will not be run

      <plugin>
        <groupId>org.scala-tools</groupId>
        <artifactId>maven-scala-plugin</artifactId>
        <configuration>
          <testSourceDir>src/test/scala</testSourceDir>
        </configuration>
        <executions>
          <execution>
            <id>scala-test-compile</id>
            <phase>process-test-resources</phase>
            <goals>
              <goal>testCompile</goal>
            </goals>
          </execution>
        </executions>
      </plugin>

[ERROR] Plugin org.scala-tools:maven-scala-plugin:2.15.2 or one of its dependencies could not be resolved: Failed to read artifact descriptor for org.scala-tools:maven-scala-plugin:jar:2.15.2: The repository system is offline but the artifact org.scala-tools:maven-scala-plugin:pom:2.15.2 is not available in the local repository. -> [Help 1]