For each of the questions a separate type of test can be defined. The most important confusion is between load and performance testing. Some documentation does not mention one or the other, some swap meanings which results in a general lack of clarity. In essence the two types of testing are mirror images of each other.
This article argues that although a load testing tool is used for each type of testing, the key difference between them is the Acceptance Criteria or objectives of each type of test. The types of test matching the non-functional questions are:
- Load Testing � How many users supported.
- Performance Testing � The performance of each transaction type.
- Stress Testing � Explores high but valid usage.
- Robustness Testing � Explores the effect of unavailability of resources.
- Endurance Testing � Checks long term running of the system.
To illustrate each type of testing a simple real world model will be used. Imagine our system is a road network connecting together houses with shops, schools and workplaces. Our transactions are users going from one point in the network to another, such as from the house to the workplace. More complicated transactions might be leaving the house to go to the school to drop off children and from there drive on to work. The functional testing that would have been done would checked that each type of transaction is possible, that roads exist between each of the network points for each type of transactions they want to follow. The following paragraphs will illustrate how the various types of load testing would apply to this model.