JUnit - Test Class Not Found In Selected Project

I'm trying to write JUnit test but I'm having trouble with the following errors:

"Test class not found in selected project" -> when running AClassTest.java

"Usage: TestRunner [-wait] testCaseName, where name is the name of the TestCase class" -> when running AClass.java

I have class AClass.java

and class AClassTest.java

They both are in the same package and there is JUnit library

Here's the code:

AClass.java:

Java Code:

public class AClass {
working code is in the last post
} mh_sh_highlight_all('java');
AClassTest.java:

Java Code: public class AClassTest extends TestCase {

working code is in the last post

} mh_sh_highlight_all('java');