Error Guessing

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Error guessing is a test technique in software testing that works by guessing the errors that might occur in the software. You test the software with inputs or scenarios that are likely to cause errors. You test how the software handles common or expected errors. Error guessing is based on your experience and intuition.

Error Guessing Examples

• You test the login feature of your website. You guess that the website may have errors with invalid username, invalid password, blank username, blank password, etc. You test the software with these inputs and validate each output.
• You test the flight booking feature of your mobile app. You guess that the software might have errors with unavailable destination, past date, expired credit card, sold out seats etc. You test the software using these test inputs and check each output.
• You test your calculator app. You guess that the software might have errors with zero division, overflow (result too large), underflow (result too small), etc. You test the software with these scenarios.
  
• You test the money transfer feature of your online banking application. You guess that the software might have errors with invalid account number, negative amount, insufficient balance, invalid OTP (one time password), timeout etc. You test your application using these test scenarios.
  

Tips for Error Guessing

• Use test techniques such as boundary value analysis, equivalence partitioning, decision table testing, etc. to design test inputs that should result in errors.
  
• Test both positive and negative scenarios to test if the software handles them appropriately.
  
• Test the relevant feature of the software that has the error handling.
• Use tools to automate tasks, such as generating test inputs, generating tests, executing tests, and reporting results.

FAQ (interview questions and answers)

1. What is the purpose of error guessing?
   Find defects that might not be detected by formal testing techniques.
2. What is the advantage of error guessing?
   It leverages the tester's experience and intuition to test the software more effectively. It can find if common and expected errors are handled appropriately by the software.
   
3. What is the disadvantage of error guessing?
   It is subjective and inconsistent, since it depends on the tester's knowledge. It focuses on error conditions, instead of the normal workflow (the happy path ☺).
   
4. Is error guessing a type of black-box testing?
   Yes, it is a technique that helps test the software without knowing its structure or code.

Remember to just comment if you have any doubts or queries.