Negative and positive testing are two sides of the same coin and as such, are often performed in tandem. With both concepts the tester is dealing with inputs and outputs. Positive testing generally tries to verify that a system does what it is supposed to do. By contrast, negative testing verifies that the system does not do what it’s not supposed to do. For example, if an application is supposed to accept x, y, and z values, a positive test would verify that the system does in fact accept those values. A negative test would attempt to input a, b, and c values in an attempt to force an error condition. The tester is trying to make the system do something it was not designed to do, such as accept values it shouldn’t or produce errors when it shouldn’t. In the most basic sense, negative testing utilizes invalid inputs to test the system’s response.
Boundary testing is the most common form of negative testing. The system should handle the boundary conditions, but they are one of the more common areas for errors. Since users can theoretically attempt to enter anything they want into data fields, negative testing must be performed to make sure only valid inputs are accepted and that meaningful and correct error messages are presented when invalid data is used. These kind of tests validate the stability of the software against a variety of incorrect influences.
Both negative and positive testing are generally done during functional testing and QA Mentor’s Testing Execution On-Demand Service and Manual Test Design and Execution Service has a rotating team of quality assurance professionals who are ready to help you with this kind of testing. We will work with your team to go over requirements, build a comprehensive test plan, design thorough test cases, execute the tests, and log defects.