OVERVIEW SO WHAT IS “NEGATIVE” TESTING ANYWAY? GOALS OF NEGATIVE TESTING NEGATIVE TESTING PROCESS ADVANTAGES OF NEGATIVE TESTING WHEN TO STOP NEGATIVE TESTING? Why you cannot ignore negative testing?

1. THE COMPLETE GUIDE FOR
NEGATIVE TESTING
DAVID TZEMACH
WWW.MACHTESTED.COM
MAY 12 2017

2. AGENDA
• OVERVIEW
• SO WHAT IS “NEGATIVE” TESTING ANYWAY?
• GOALS OF NEGATIVE TESTING
• NEGATIVE TESTING PROCESS
• ADVANTAGES OF NEGATIVE TESTING
• WHEN TO STOP NEGATIVE TESTING?
• WHY YOU CANNOT IGNORE NEGATIVE TESTING?

3. OVERVIEW

4. A QUALITY ASSURANCE PROCESS CONTAINS MANY ACTIVITIES SUCH AS LEARNING,
DESIGNING, AND TESTING THAT ARE PERFORMED TO VALIDATE THAT THE
CUSTOMER WILL RECEIVE THE APPLICATION WITH THE HIGHEST QUALITY AS
POSSIBLE.
DURING THESE ACTIVITIES, THE TESTING TEAMS WILL TEST THE APPLICATION WITH
DIFFERENT TEST TECHNIQUES, METHODOLOGIES, AND TOOLS THAT WILL ALLOW
THEM TO INCREASE THE CHANCES TO FIND THE MAXIMUM DEFECTS AS POSSIBLE TO
ENSURE THAT THE CLIENT CAN USE THE SOFTWARE AS EXPECTED.
NOW, FINDING DEFECTS IN ANY APPLICATION IS PROBABLY THE MAIN TASK FOR
ANY TESTER, DUE TO THE IMPORTANCE OF THIS TASK, THE TESTER MUST COVER
TWO MAIN ASPECTS:
THE POSITIVE SIDE
TEST THE APPLICATION AGAINST THE PRELIMINARY REQUIREMENTS AND
SPECIFICATIONS, THIS TESTS WILL DETERMINE IF THE APPLICATION PERFORMS AS
EXPECTED.
THE NEGATIVE SIDE
WHILE THE POSITIVE SIDE OF TESTING IS CRUCIAL AND IMPORTANT, THE NEGATIVE
SIDE IS SOMETIMES EVEN MORE IMPORTANT, DURING THIS TESTS, WE WILL
VALIDATE THAT THE APPLICATION CAN HANDLE FAILURES OR ANY ABNORMAL
SITUATIONS THAT CAN CAUSE UNNECESSARY RISKS OR AFFECT THE REQUIREMENTS
AND SPECIFICATIONS.

5. SO WHAT IS “NEGATIVE”
TESTING ANYWAY?

6. NEGATIVE TESTING IS….
NEGATIVE TESTING IS A TESTING PROCESS WHERE THE TESTER WILL USE AN
INVALID DATA AS AN INPUT TO THE APPLICATION FUNCTIONALITIES. DURING
THIS TESTS, THE TESTER WILL VALIDATE WHETHER THE APPLICATION CAN
HANDLE THIS TYPE OF INPUTS AND IF THE APPLICATION BEHAVES AS EXPECTED
AND DEFINED IN THE PRELIMINARY REQUIREMENTS AND SPECIFICATIONS.

7. GOALS OF
NEGATIVE
TESTING

8. THE REAL PURPOSE OF NEGATIVE TESTING
IT IS VERY IMPORTANT TO UNDERSTAND THE REAL PURPOSE OF NEGATIVE TESTING, AND WHY YOU MUST COMBINE
THEM IN ANY TESTING PROCESS, THIS LIST WILL ALLOW YOU TO UNDERSTAND WHAT NEGATIVE TESTING IS ALL ABOUT:
• VALIDATE THAT THE APPLICATION WILL NOT DO ANYTHING THAT IT IS NOT SUPPOSED TO DO.
• VALIDATE HOW THE SOFTWARE WILL RECOVER FROM FAILURES THAT CAUSED BY INVALID DATA.
• TO DETERMINE UNDER WHICH SCENARIOS THE APPLICATION CAN CRASH.
• IDENTIFICATION OF THE WEAKNESSES POINTS OF THE APPLICATION.
• VALIDATE THAT THE APPLICATION CAN ABNORMAL SITUATIONS WHERE THE USER USES AN INVALID INPUT
(NOTIFICATIONS, RESPONSE TIME, ERRORS, LOGS….).
• VALIDATE THAT THE DIFFERENT ASPECTS THAT ARE NOT DOCUMENTED IN THE POSITIVE REQUIREMENTS AND
SPECIFICATIONS.

9. NEGATIVE
TESTING PROCESS

10. THE FOUR PHASES OF NEGATIVE TESTING
PROCESSPHASE 1: KNOWLEDGE GATHERING
THE TESTER WILL GATHER ALL INFORMATION THAT IS NEEDED TO DESIGN
THE NEGATIVE TEST CASES, DURING THIS ACTIVITY, THE TESTER SHOULD
READ THE APPLICATION DOCUMENTATION, REVIEW THE APPLICATION DESIGN
AND GATHER ALL INFORMATION THAT HE CAN USE PRIOR TO DESIGN THE
TEST CASES.
PHASE 2: TEST DESIGN
BASED ON THE INFORMATION GATHERED IN THE FIRST ACTIVITY, THE TESTER
HAS THE RELEVANT INFORMATION THAT HE CAN NOW USE TO DESIGN THE
NEGATIVE TEST SCENARIOS INCLUDING THE TESTING DATA THAT HE WILL USE
THROUGHOUT THE TEST PROCESS.
PHASE 3: TEST EXECUTION
THE TESTER WILL RUN THE TESTS AND REPORT ANY INCIDENT THAT WAS
FOUND DURING THIS PROCESS.
PHASE 4: EXAMINE THE TEST RESULTS
ONCE ALL TESTS ARE DONE, THE TEST RESULTS ARE REVIEWED AND
ANALYZED TO DETERMINE IF FURTHER TESTS ARE NEEDED.

11. ADVANTAGES OF
NEGATIVE TESTING

12. THE MAIN ADVANTAGES OF NEGATIVE TESTING(A)
1. NEGATIVE TESTING WILL ALLOW YOU TO INCREASE THE
CONFIDENCE IN THE PRODUCT, THE QUALITY OF THE
APPLICATION IS ALWAYS DETERMINED BY BOTH POSITIVE
AND NEGATIVES SCENARIOS.
2. USING NEGATIVE TESTING, WE CAN SHOW THAT THE
APPLICATION DOES NOT WORK.
3. NEGATIVE TESTING WILL DEMAND MORE CREATIVITY AND
THINKING FROM THE TESTERS TO THINK ABOUT TEST CASES
THAT ARE NOT SPECIFIED IN THE BASIC REQUIREMENTS AND
SPECIFICATION.
4. ONCE A NEGATIVE SCENARIO THAT CAUSED THE
APPLICATION TO FAIL IS FIXED, WE WILL REMOVE ONE
MORE RISK THAT WILL INCREASE THE STABILIZATION OF THE
SOFTWARE.

13. THE MAIN ADVANTAGES OF NEGATIVE TESTING(B)
1. NEGATIVE TESTING WILL ALLOW US TO
UNDERSTAND THE LIMITATIONS OF THE
APPLICATION.
2. WE CAN USE NEGATIVE TESTING IN ALL
LAYERS OF TESTING (UNIT, COMPONENT,
INTEGRATION, SYSTEM AND END-TO-END).
3. NEGATIVE TESTS ARE USED TO COVER
MANY ASPECTS THAT ARE NOT COVERED IN
THE PROCESS OF POSITIVE TESTING.
4. NEGATIVE TESTING WILL ALLOW US TO
GRACEFULLY HANDLE ERRORS AND
NOTIFICATIONS THAT MAY POP-UP TO THE
USER.

14. WHEN TO STOP
NEGATIVE TESTING?

15. SO WHEN SHOULD WE STOP RUN NEGATIVE SCENARIOS..?
THERE IS NO “END” DATE TO STOP NEGATIVE TESTING,
SIMILAR TO ANY OTHER TESTING PROCESS, YOU WILL
STOP TESTING ONLY WHEN THE RISKS ARE REMOVED
AND THERE ARE NO REMAINING ISSUES THAT CAN
AFFECT THE USER EXPERIENCE AND THE STABILITY OF
THE APPLICATION.
ANOTHER TESTING STOPPER THAT IS WELL KNOWN IS
THE PROJECT DEADLINES, ALTHOUGH YOU MAY HAVE
THOUSANDS OF TEST CASES YOU WILL NEVER SUCCEED
TO RUN THEM ALL DUE TO THE TIME LIMITATIONS AND
THE RELEASE COMMITMENTS, THEREFORE YOU WILL
NEED TO PRIORITIZE YOUR TESTS IN ORDER TO FIND THE
MOST IMPORTANT ISSUES IN THE SPECIFICALLY
AVAILABLE TIME FRAME.

16. WHY YOU CANNOT
IGNORE NEGATIVE
TESTING?

17. THE IMPORTANCE OF NEGATIVE TESTING (A)
1. NEGATIVE TESTING WILL ALLOW YOU TO FIND
PROBLEMS THAT ARE UNIQUE FOR SPECIFIC
INTEGRATION.
2. POSITIVE TESTING WILL NOT ALLOW YOU TO
UNDERSTAND HOW EXTERNAL ARTIFACTS CAN
AFFECT THE APPLICATION FUNCTIONALITY (LOW
DISK SPACE, LOW MEMORY, LOW BANDWIDTH,
SERVICE CRUSHES ETC.)
3. AS MANY EXCEPTIONS THAT ARE FOUND AND
REMOVE, THE BETTER QUALITY YOU ACHIEVE.
4. NEGATIVE TESTING WILL ALLOW US TO IMPROVE
THE NOTIFICATIONS IN CASE OF FAILURES.
5. IF YOU FAIL TO FIND A SOFTWARE EXCEPTION, THE
SYSTEM WILL BE RELEASED AS IF NO PROBLEM HAS
BEEN FOUND, THIS CAN LEAD TO A MAJOR ISSUE
ON ALL SYSTEM LEVELS.

18. THE IMPORTANCE OF NEGATIVE TESTING (B)
1. USING NEGATIVE TESTING, WE WILL ENFORCE THE
APPLICATION GUIDELINES AND DEMANDS, THESE
ENFORCEMENTS WILL PREVENT UNNECESSARY AND
UNEXPECTED SCENARIOS THAT MAY RAISE WILL THE
CUSTOMER INTERACTS WITH THE APPLICATION.
2. NEGATIVE TESTING WILL ALLOW
3. NEGATIVE TESTING WILL ALLOW YOU TO STOP THE
APPLICATION EXECUTION IN CASE OF A FAILURE UNTIL
THE PROBLEM IS FIXED.
4. IF YOU RUN ONLY “POSITIVE” SCENARIOS, YOU WILL
FAIL TO UNDERSTAND WHAT ARE THE APPLICATION
UPPER AND LOWER LIMITS.
5. A SMALL PROBLEM THAT WE FAIL TO FIND DURING THE
TESTING CYCLES CAN (AND PROBABLY WILL) BE
ACCELERATE AND BECOME A MAJOR ISSUE.

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