Paper work on Negative testing

What is negative testing?

Negative testing is the testing done to show the application or system does something that it is not supposed to do. A negative testing is the logic trying to get the application or system to do something differently than what it is supposed to do.

Negative testing = (showing errors when not supposed to) + (not showing error when supposed to)

A negative test is more trying to get the application or system to do something differently than it was designed to do.


Testing the system using negative data is called “negative testing”


Why negative testing?

Basically,when the developers develop the application they will be focused only on the positive thinking that the application should meet the requirements of the application. So they don’t think in negatively, that the application should not do, and they think about only what the application should do. So in order to overcome this negative testing should be done.



Difference between negative and positive testing

Negative testing:

Doing something it was not supposed to do. Not doing something it was supposed to do.


Positive testing:

Not doing something that was not supposed to do. Doing something it was supposed to do.






A negative testing is a technique which includes boundary value analysis and equivalence partitioning testing.

Equivalence partitioning: we use this technique to
1. To reduce the number of test cases on fields

2. To test field range of 30-60, we have three equivalence classes – any thing below 30 as “in-valid-too low”, 30-60 as “valid”, any thing above 60 as “invalid-too-high”

3. All values in an equivalence class are considered to be of similar importance and all classes of the same data type.


Boundary value analysis:

Boundary values are the edges of the range. It is a refinement of equivalence partitioning which focuses on the boundaries.

For the range of 30-60, boundaries are 29, 30, 31 on the lower side and 59, 60, 61 on the upper side.

Basing on the above example the field should take only the values between 30 and 60.Testing by passing the values in between 30 and 60 is called “positive testing”. Testing by passing values 29, 31, 59, 61 is called “negative testing” (by passing these values we could be able to find weather the application is working for the values for which it should not work).

Examples: 1. Entering special characters for phone number.
2. Entering password less than 8 characters for which it has to take minimum of 8 characters.
3.Entering numbers for user id.