# Testing Techniques

Equivalence Partitioning: In this method the input data is divided into different equivalence data classes. EP determines the number of test cases to be generated for a given scenario. Equivalence class represents a set of valid or invalid states for input conditions. In equivalence partitioning, data is selected in such a way that it gives as many different output as possible with the minimal set of data.

Equivalence classes may be defined according to the following guidelines:

1. If an input condition specifies a range, one valid and two invalid equivalence classes are defined.
2. If an input condition requires a specific value, then one valid and two invalid equivalence classes are defined.
3. If an input condition specifies a member of a set, then one valid and one invalid equivalence class are defined.
4. If an input condition is Boolean, then one valid and one invalid equivalence class are defined.

Boundary Value Analysis: This is also a Black Box Testing Technique which consider on the Corner cases or the boundaries of the input domain rather than its center. More application errors occur at the boundaries of input domain.

For example If we want to test a field from 5 to 20, boundary values will be 4 5 6 and 19 20 21
The left hand value is called the lower boundary e.g. 5 here in this example and the Right side value 20 is called the Upper boundary and hence the selection of values is
a. Upper boundaries +1 -1

20+1=21 (outside right boundary)

20-1=19 (inside right boundary)

b. Lower boundaries +1 -1

5+1=6 (inside left boundary)

5-1=4 (outside left boundary)

Error Guessing: Ability to guess based on previous experience in Software testing environment.

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