Warnings from tests that are excluded during gwt:test

I currently have a project setup that combines standard JUnit 4 tests along with the GWTTestCase tests. I have it configured[1] based on the testing guide for how to separate the tests. The build works however I get warning for tests that are supposed be excluded from being ran during the gwt:test goal.

[INFO] [surefire:test

]
[INFO] Surefire report directory: /home/mw010351/workspaces/preferences/example-project/target/surefire-reports

-------------------------------------------------------
T E S T S
-------------------------------------------------------
Running com.example.project.client.SimpleTest
Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.022 sec

Results :

Tests run: 1, Failures: 0, Errors: 0, Skipped: 0

[INFO] [gwt:test

]
[INFO] using GWT jars for specified version 2.0.0
[INFO] establishing classpath list (scope = test)
[INFO]
[INFO] -------------------------------------------------------
[INFO] T E S T S
[INFO] -------------------------------------------------------
[INFO] Running junit.framework.TestSuite@11975b59
[INFO] Validating newly compiled units
[INFO] [ERROR] Errors in 'file:/home/mw010351/workspaces/preferences/example-project/src/test/java/com/example/project/client/SimpleTest.java'
[INFO] [ERROR] Line 10: No source code is available for type org.junit.Assert; did you forget to inherit a required module?
[INFO] Validating newly compiled units
[INFO] [ERROR] Errors in 'file:/home/mw010351/workspaces/preferences/example-project/src/test/java/com/example/project/client/SimpleTest.java'
[INFO] [ERROR] Line 10: No source code is available for type org.junit.Assert; did you forget to inherit a required module?
[INFO] Hello World
[INFO] Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 11.818 sec
[INFO]
[INFO] Results :
[INFO]
[INFO] Tests run: 1, Failures: 0, Errors: 0, Skipped: 0
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESSFUL
[INFO] ------------------------------------------------------------------------

[1] - http://mojo.codehaus.org/gwt-maven-plugin/user-guide/testing.html