SOFTWARE ENGINEERING

Detailed explanation-1: -Test cases should be developed for both valid and invalid input conditions. A tester must not assume that the software under test will always be provided with valid inputs. Inputs may be incorrect for several reasons.

Detailed explanation-2: -Valid input-subset of functional tests using valid input data. Invalid input-subset of functional tests using invalid input data. Invalid input data can be expected (such as the user fails to enter data in a required field) or unexpected (if something can be done, a user will do it)

Detailed explanation-3: -Negative testing is a method of testing an application or system that ensures that the plot of the application is according to the requirements and can handle the unwanted input and user behavior. Invalid data is inserted to compare the output against the given input.

Detailed explanation-4: -Negative Testing is testing process where the system validated against the invalid input data. A negative test checks if a application behaves as expected with its negative inputs.