Finding of Errors - Primary Goal
Trying to prove that software does not work. Thus, indirectly verifying that software meets requirements
Software testing is the process of testing the functionality and correctness of software by running it. Software testing is usually performed for one of two reasons:
(1) defect detection
(2) reliability or Process of executing a computer program and comparing the actual behavior with the expected behavior
What is the goal of Software Testing?
* Demonstrate That Faults Are Not Present
* Find Errors
* Ensure That All The Functionality Is Implemented
* Ensure The Customer Will Be Able To Get His Work Done
Modes of Testing
* Static Static Analysis doesn¡¦t involve actual program execution. The code is examined, it is tested without being executed Ex: - Reviews
* Dynamic In Dynamic, The code is executed. Ex:- Unit testing
* White box testing Use the control structure of the procedural design to derive test cases.
* Black box testing Derive sets of input conditions that will fully exercise the functional requirements for a program.
* Integration Assembling parts of a system
Verification and Validation
* Verification: Are we doing the job right? The set of activities that ensure that software correctly implements a specific function. (i.e. The process of determining whether or not products of a given phase of the software development cycle fulfill the requirements established during previous phase). Ex: - Technical reviews, quality & configuration audits, performance monitoring, simulation, feasibility study, documentation review, database review, algorithm analysis etc
* Validation: Are we doing the right job? The set of activities that ensure that the software that has been built is traceable to customer requirements.(An attempt to find errors by executing the program in a real environment ). Ex: - Unit testing, system testing and installation testing etc
What's a 'test case'?
A test case is a document that describes an input, action, or event and an expected response, to determine if a feature of an application is working correctly. A test case should contain particulars such as test case identifier, test case name, objective, test conditions/setup, input data requirements, steps, and expected results
What is a software error ?
A mismatch between the program and its specification is an error in the program if and only if the specifications exists and is correct.
Risk Driven Testing
What if there isn't enough time for thorough testing?
Use risk analysis to determine where testing should be focused. Since it's rarely possible to test every possible aspect of an application, every possible combination of events, every dependency, or everything that could go wrong, risk analysis is appropriate to most software development projects. This requires judgement skills, common sense, and experience.
Considerations can include:
- Which functionality is most important to the project's intended purpose?
- Which functionality is most visible to the user?
- Which aspects of the application are most important to the customer?
- Which parts of the code are most complex, and thus most subject to errors?
- What do the developers think are the highest-risk aspects of the application?
- What kinds of tests could easily cover multiple functionality?
Whenever there's too much to do and not enough time to do it, we have to prioritize so that at least the most important things get done. So prioritization has received a lot of attention. The approach is called Risk Driven Testing. Here's how you do it: Take the pieces of your system, whatever you use - modules, functions, section of the requirements - and rate each piece on two variables, Impact and Likelihood.