Brief Introduction of Black Box Test Design Techniques

# By These techniques We could 

* Pick all the test cases in a systematic manner
* Save lots of testing time
* Get the good test coverage

Knowledge of the internal code structure of the application under Test is not necessary to use these black box test techniques.

# List of Black Box Test design Techniques-
*Equivalence Partitioning
*Boundary Value Analysis
* Decision Table
* State Transition
* Exploratory Testing
* Error Guessing

Equivalence Partitioning-

This is also known as equivalence Class Partitioning. Using this technique, We divide the test conditions into group.
From Each group, we test only one condition. If a condition from group works then all the condition from that group work.
This reduces lots of rework and also gives the good test coverage. This also Saves lots of time by reducing total number of test
cases that must be developed.
For example-
There is a field which accepts numeric values. In this case, we split the test conditions like-
* Enter numeric value
* Enter alphanumeric value
* Enter alphabets and so in.

Boundary Value Analysis-

Using this technique, we take the test conditions as partitions and design the test cases by getting the boundary values of the partition.
The test conditions on either side the boundary are called boundary values. In this we have to earn both valid boundaries (from the valid partitions) and invalid boundaries (from the invalid partitions).
For example-
If we want to test a field which should accept only amount more than 10 and less than 20 then we take the boundaries as 10 minus 1,10,10 plus
1,20 minus 1, 20, 20 plus 1. Instead of using much of test data, We just use 9,10,11,19,20 and 21.

Decision Table-

It is also known as cause effect table. This technique is appropriate for functionalities which has logical relationships between inputs
i.e., if-else logic.
Using this technique, We deal with combination of inputs. To meet the test cases with decision table, we consider conditions and actions.
We take conditions as input and actions as output.

State Transition-

Using State Transition, We pick the test cases from the application where we need to test different system transitions. We can apply this 
If any application gives a different output for the same input, depending upon what has happened in the earlier state.
For example- vending machines and Traffic Lights.

Exploratory Testing-

Mostly this process will be carried out by domain experts. Domain experts perform testing just by exploring the functionalities of the application
without having the prior knowledge of the requirements.

Error Guessing-

It is used to find the bugs in the software application based on tester's prior experience. In this, we don't follow any specific rules.
It is an unplanned testing technique.