Initialization error: Unrooted Tests

When I try to execute a JUnitTestSuite with the new Run As →Scala JUnit Test I get :

UITestSuite.UITestSuite
Unrooted Tests
initializationError(org.junit.runner.manipulation.Filter)
java.lang.Exception: No tests found matching Method UITestSuite(scala.tools.eclipse.ui.UITestSuite) from org.junit.internal.requests.ClassRequest@3f57fb52
	at org.junit.internal.requests.FilterRequest.getRunner(FilterRequest.java:37)
	at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.<init>(JUnit4TestReference.java:33)
	at org.eclipse.jdt.internal.junit4.runner.JUnit4TestMethodReference.<init>(JUnit4TestMethodReference.java:25)
	at org.eclipse.jdt.internal.junit4.runner.JUnit4TestLoader.createTest(JUnit4TestLoader.java:54)
	at org.eclipse.jdt.internal.junit4.runner.JUnit4TestLoader.loadTests(JUnit4TestLoader.java:38)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:452)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)

The TestSuite is as follows:

package scala.tools.eclipse.ui

import org.junit.runner.RunWith
import org.junit.runners.Suite

@RunWith(classOf[Suite])
@Suite.SuiteClasses(Array(
//  classOf[TestScalaIndenter],
  classOf[BracketAutoEditStrategyTest],
  classOf[LiteralAutoEditStrategyTest],
  classOf[StringAutoEditStrategyTest]))
class UITestSuite

This error occurs only when the code should be executed immediately after the editor is opened. After doing some changes in the code (adding new line for example) and restarting the tests the errors do not occur any more.