Question on addTest method of Junit

[Boyan Wu]

Hi, all, I got a question on the addTest method of TestSuite class. I wrote a TestSuite class with the static suite method like this:
public static Test suite() {
TestSuite suite = new TestSuite();
suite.addTestSuite(CalTest.class);
return suite;
}
where CalTest is a class inheriting from TestCase class. This part of code is ok. However if I change to this
public static Test suite() {
TestSuite suite = new TestSuite();
suite.addTest(new CalTest()); --- difference
return suite;
}
The launch of the testrunner fails and reports a AssertionFailedError. On the JUnit api doc, the addTest(Test test) method does not have any explanation. I would like to know what is wrong with the second method.

[Jeanne Boyarsky]

The default constructor doesn't tell Junit which test case to add to the suite. You need to call the constructor that takes a string. For example,

public static Test suite() {
TestSuite suite = new TestSuite();
suite.addTest(new CalTest("test_nameOfTest")); --- difference
return suite;
} 

However, this only runs one test. If you want to run all the tests, as I suspect, you can add the whole test suite. There are two ways of doing this (one you already had)

suite.addTestSuite(CalTest.class);
suite.addTestSuite(CalTest.suite());

[Boyan Wu]

Thank you, Jeanne. You solved my puzzle. I used to think the fName private field in the TestCase class indicates the name of the test class, a usual way in designing class though, it turns out this is the method name I want to run.