Positive testing is performed to verify the correct functioning of different entities of a software product along the lines of expected behaviour in response to valid data input. Software applications like website and mobile apps require entities like text boxes and text forms. Positive testing tests the correct functioning of these entities. This ensures that the product meets the expectations and specifications of the customer.
The main goal of positive testing is check if a product gives an error message when it should and doesn't respond in the negative when it fed with valid data. To better understand this form of testing, it's quite helpful to make use of an example.
Let's take the example of a password box in an application requiring the use of alpha numeric characters to secure transaction for online recharge coupon. The password box will pass the test for positive testing if it allows the transaction to take place based on correct feeding of input data, which is the correct password employing the use of BOTH alphabetical AND numerical characters.
Positive testing plays an important role for verification of normal functioning of basic entities found in most websites such as option for logging in and Text boxes for feeding of general data during form filling. It is necessary to ensure confidence in quality of such features of a product that is bug free and suffers no glitches.