Test cases for Black box

For Black box testing, the test cases can be generated by using all or a combination of the below techniques.

Graph Based : Software testing begins by creating a graph of important objects and their relationships and then devising a series of tests that will cover the graph so that each objects and their relationships and then devising a series of tests that will cover the graph so that each object and relationship is exercised and error is uncovered.

Error Guesssing – Error Guessing comes with experience with the technology and the project. Error Guessing is the art of guessing where errors can be hidden. There are no specific tools and techniques for this, but you can write test cases depending on the situation. 

Boundary Value Analysis (BVA) is a test data selection technique (Functional Testing technique) where the extreme values are chosen. Boundary values include maximum, minimum, just inside/outside boundaries, typical values, and error values. The hope is that, if a system works correctly for these special values then it will work correctly for all values in between. 

Equivalence partitioning is a testing method that divides the input domain of a program into classes of data from which test cases can be derived.

Compasrision Testing – There are situations where independent versions of software be developed for critical applications, even when only a single version will be used in the delivered computer based system. It is these independent versions which form the basis of a black box testing technique called Comparison testing or back-to-back testing.

The Orthogonal Array Testing Strategy (OATS) is a systematic, statistical way of testing pair-wise interactions by deriving a suitable small set of test cases (from a large number of possibilities).

Testing Types & Testing Techniques

Testing types deal with what aspect of the computer software would be tested, while testing techniques deal with how a specific part of the software would be tested.

That is, testing types mean whether we are testing the function or the structure of the software. In other words, we may test each function of the software to see if it is operational or we may test the internal components of the software to check if its internal workings are according to specification.

On the other hand, ‘Testing technique’ means what methods or ways would be applied or calculations would be done to test a particular feature of a software  (Sometimes we test the interfaces, sometimes we test the segments, sometimes loops etc.) 

Stop Testing

Time and again the most important question that haunts a tester – when are you stopping your test?

Well’ there is no right or wrong answer for this. But definetly you can concur at the time to stop testing using these items

1. All high priority bugs are fixed

2.The bug convergence shows good result

3. ZBB ( Zero Bug Bounce) has been achieved

4.The testing budget is achieved

5.The project duration is completed 🙂

6. The risk in the project is under acceptable limit

Practically item # 6 would be the main and most acceptable solution to stop testing.  Now what risks need to be monitored for these answers ? . I would go with – Test coverage, Number of test cycles & priority of open  bugs

Deliverables @ various phases

This diagram does not depict when and where are the test plan and test strategy documents generated.Ideally, these documents are ready before you begin the test activities

Test Activities during phases

Test activities vary with the model and also on the type of project. So here is a generic list of items that needs to be done. You can always do it at any point when enough data is available.

1. Requirement Phase :

• Invest in analysis at the begining of the project
• Start developing the test set at the requirement analysis phase
• The correctness, consistency and completeness of the requirements should be analysed.

2. Design Phase :

• Analysis of design to check its completeness and consistency
• Analysis of design to check whether it satisfies the requirements
• Generation of test data based on design
• Setting up of test bed

3. Programming/Coding Phase :

• Check code for consistency with design
• Perform system testing in an organized manner – Buddy testing, feature testing, integration testing, System testing etc
• Use available tools
• Apply stress to the program
• Test one at a time
• Measure test coovergae

4. Maintanence Phase :

• Retest/Regress