Error Guessing
In Error Guessing you prepare a list of errors that are likely to occur in a certain area of the system and then designing a set of test cases to check for these expected errors. It is based on the ability of the tester to draw on his past experience, knowledge and intuition to guess where bugs will be found in the software under test. Error guessing is an ad-hoc approach to test design mostly. Zero input values and input values that cause zero outputs are examples of where a tester may guess an error could occur.
Two familiar examples of error prone situations are division by zero and calculating the square root of a negative number. Either of these will result in system errors and garbled output. Test data that appears very likely prone to errors February 29, 2000, Special Characters, Zero inputs etc.
Error Guessing is summarized below [Source]:
Based on your experience, try to guess which areas of the program will have errors in them.
Create tests for those areas.
Use lists of errors gathered from code reviews and inspections to give you guidance.
Keep a list of errors you’ve found in other pieces of code.