Strategies and methods for test case design II

Strategies and methods for test case design

Today we are talking about how to get an approach for writing a good test case. Developers cannot prevent or eliminate all the defects raised in the application during implementation. That's why the application should be tested before deliver to the customer.
Before starting the execution, we need to identify test scenarios and write test cases for each identified scenarios. Test case is test description which needs to be executed to verify the functionality or feature of the application. A good test case have a good possibility of finding defects.
For designing effective test cases, there are two basic strategies that can be used.

1. Black box test strategies
2. White box test strategies

Test Strategies	Sources	Testing Techniques
Black Box	Functional requirement specification	Equivalence partitioning
	Business requirement specification	Boundary value analysis
	Domain knowledge	State Transition Testing
		Decision table
		Use case testing
		Error guessing
White Box	High level design	Statement coverage
	Control flow graph	Decision coverage
	Cyclomatic complexity	Condition coverage

Black Box approach to test case design
As a foundation for designing black box test cases, we are mainly considering inputs and outputs . Testers should choose what are the possible valid and invalid inputs. Exhaustive testing is not possible. Exhaustive testing means testing with all possible inputs. Therefore the combination of different testing techniques are used to detect different types of defects. Sources such as functional requirement specification, business requirement specification and domain knowledge are used to determine test scenarios of application. Equivalence partitioning, Boundary value analysis, State Transition Testing, Decision table,Use case testing and Error guessing are testing techniques of black box testing strategy.
White Box approach to test case design
For designing white box test cases, testers should have a knowledge of internal logic structure of the application. The main purpose of this strategy is to determine all the logics are implemented properly. Sources such as High level design, Control flow graph and Cyclomatic complexity are used to determine test scenarios of application. Statement coverage, Decision coverage and Condition coverage are testing techniques of white box testing strategy.

Hope to cover all the testing techniques individually and See you soon with another Strategies and methods for test case design tutorial........
Thanks,
Dananji Withana