How to run a spark example program in Intellij IDEA

First on the command line from the root of the downloaded spark project I ran

mvn package

It was successful.

Then an intellij project was created by importing the spark pom.xml.

In the IDE the example class appears fine: all of the libraries are found. This can be viewed in the screenshot.

However , when attempting to run the main() a ClassNotFoundException on SparkContext occurs.

Why can Intellij not simply load and run this maven based scala program? And what can be done as a workaround?

As one can see below, the SparkContext is looking fine in the IDE: but then is not found when attempting to run:

The test was run by right clicking inside main():

.. and selecting Run GroupByTest

It gives

Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/spark/SparkContext
    at org.apache.spark.examples.GroupByTest$.main(GroupByTest.scala:36)
    at org.apache.spark.examples.GroupByTest.main(GroupByTest.scala)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at com.intellij.rt.execution.application.AppMain.main(AppMain.java:120)
Caused by: java.lang.ClassNotFoundException: org.apache.spark.SparkContext
    at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    ... 7 more

Here is the run configuration: