Testing - Key challenges of software testing

What are the key challenges of software testing?

Key Challenges of s/w testing:
1. Testing considered late in project
2. Requirements not testable
3. Integration is done after all components have been developed: This might result into full testing not being covered.
4. Complete testing is not possible

What are the roles of glass-box and black-box testing tools?

Glass Box (or white box) testing is the process of giving i/p to the system and checking how the system processes i/p to generate o/p
Black Box testing is the process of giving i/p to the system and checking if the system is giving correct o/p without bothering how the o/p is generated.
As we can see from the definitions, the role of black box testing is to ensure that the o/p generated is correct. And role of white box testing is to ensure that methods used to generate the o/p are correct.

What is the difference in writing the test cases for Integration testing and system testing?

Integration testing is done at module level when various modules are integrated with each other to form a system or sub-system. Its main purpose is to ensure that interfaces between various modules are working properly; i.e. modules which are working individually are also working correctly together.
System testing is done on a complete, integrated system to evaluate the system’s compliance with its specified requirements. It validates that the system meets its functional and non-functional requirements.
From these definitions, it is clear that the purpose of Integration and purpose of System Testing are different. Therefore, Integration test cases focus more on the interfaces between modules (interface integrity) - the data transfer and their interaction with each other. System test cases focus on testing the product as a whole; i.e. whether the functional, non-functional requirements of the System are met or not. Since System Testing is the final phase before delivery of the product, System test cases should pinpoint configuration related errors along with testing for performance, security, reliability etc.

What methodologies have you used to develop test cases?

I have used following 4 types of Methodologies:
1. Boundary value analysis
2. Equivalence partitioning
3. Error guessing
4. Cause effect graphing