Why Error Guessing is significant in testing?

Error guessing is a testing technique based on guessing. It is not just guessing, but the skill of a tester. The tester acquires this skill from his prior experience in testing. This technique has got important significance in testing, and is discussed below.

We cannot develop a system which is error free. Even-though a system is tested indefinite times, a 100% error free system cannot be achieved. But if the person has prior experience on what he is testing, he can assume the possible errors that might occur and thus he can include those test cases also, making his testing more effective. Error guessing mainly depends on the skills and understanding of the tester. One of the examples is, while testing date fields, the case 'Feb 29' would definitely spring into the mind of an experienced tester.

Other similar examples are:

• Division by zero.
• Submitting a form without entering values.
• Entering invalid values(alphabets for digits and vice-versa).
• Replacing @ and dot(.) in email ids (eg: tester.gmail@com).
• Ignoring the default maximum and minimum characters to be entered in some fields (that is entering values greater than or less than the expected values).

Error guessing is considered an effective test case design technique, since the technique covers all possible test cases. By implementing this technique, a tester can save his time spent on testing. So strengthen your experience in testing and widen your Error Guessing. Have a good testing day! :)