Negative testing is a method of testing an application or system to improve the likelihood that an application works as intended/specified and can handle unexpected input and user behavior.
This shows that the application is able to handle improper user behavior.
Negative testing is done to check that the product deals properly with the circumstance for which it is not programmed.
Positive testing ensures that the application does what it is implied for and performs each function as expected.
Example There are two basic techniques that help to write the sufficient test cases to cover most of the functionalities of the system.