GWT... alguém domina? Preciso fazer uma classe de teste

import static org.junit.Assert.assertTrue;

import org.junit.Test;

/**
 * GWT JUnit tests must extend GWTTestCase.
 */
public class TesteGWTTestCase {

  /**
   * Must refer to a valid module that sources this class.
   */
  public String getModuleName() {
    return "br.com.Principal";
  }

  /**
   * Add as many tests as you like.
   */
  @Test
  public void testFwlogin() {
	  assertTrue(2 + 2 == 4);
  }
}