1. Positive and negative testing
Positive testing tries to prove that a given product does what it is supposed to do.
When a test case verifies the requirements of the product with set of expected o/p, it is called Positive TC.
Example Lock and Key

2. “POSITIVE TESTING IS DONE TO VERIFY THE KNOWN TEST CONDITIONS”

3. Req No
INPUT 1
INPUT 2
CURRENT STATE
EXPECTED OUTPUT
BR01
KEY09
Turn CW
Unlocked
Locked
BR02 NC
BR03
Turn ACW
BR04
Unlock
BR05
Hairpin
No Change

4. Consider the first row- Current state of lock is unlock and use key and turn it clockwise, the expected output is locked.
During execution the test results is locking, then the TC is passed. This is an example for “Positive test condition” for positive testing.

5. Consider the last row
Current state of lock is locked . Using a hairpin and turn it CW should not cause a change in state or cause damage to the lock.
After execution, there is no changes, then positive test case is passed. This is example of a “negative test condition” for positive testing.

6. Negative Testing
Negative Testing is done to show that the product does not fail when an unexpected input is given.
Negative testing covers scenarios for which the product is not designed and coded.
Test conditions termed as Unknown condition.
A negative test would be a product not delivering an error when it should or delivering an error when it should not.

7. Negative Test Cases INPUT 1 INPUT 2 CURRENT STATE EXPECTED OUTPUT
Some other lock’s key
Turn CW
Lock
Turn ACW
Unlock
Thin piece of wire
Hit with a stone

8. In the above table, there are no requirement numbers.
Since negative testing focuses on test conditions that lie outside the specification.
Here all the test conditions are outside the specification, they cannot be categorized as positive and negative test conditions.

9. Difference- PT & NT Differ by their coverage
For PT if all documented requirements and test conditions are covered, then coverage is 100%.
If specifications are very clear- coverage can be achieved.
Negative Testing
100 percentage coverage is not possible.
Negative testing requires high degree of creativity.
NEGATIVE TESTING IS DONE TO BREAK THE PRODUCT WITH UNKNOWNS