A base test class which adds the following capabilities to the test harness:
Automatically starts an embedded Jetty server which loads the application.
Starts a transaction before the test begins and rolls the transaction back after
the test completes so that nothing is written to the database.
Creates a List of EnumeratedValue DTOs, use to initialize database for testing
last index value minus initial index value determines size of List
EnumeratedValues are created with current index value to give each object field pseudo unique values
Extending DataModelValidator to override call to Application.getApplicationContext()
for messages, since ApplicationContext does a GWT.create() which can't be called from
JUnit tests.