Negative Test and Positive Test

Terms like "negative test" and "positive test" are more of a concept than a strict activity. In both instances you are dealing with an input, an action, and an output. The action acts upon the input to derive a certain output. So a test case (and thus a good test) is just one that deals with those three things. Both test cases can produce errors and, in fact, some say that the success of a test case is based upon the probability of it finding new errors in an application.