During development, you may run a single test class repeatedly. To run this through Maven, set the test property to a specific test case.
mvn -Dtest=TestCircle test
The value for the test parameter is the name of the test class (without the extension; we'll strip off the extension if you accidentally provide one).
You may also use patterns to run a number of tests:
mvn -Dtest=TestCi*le test
And you may use multiple names/patterns, separated by commas:
mvn -Dtest=TestSquare,TestCi*le test