Testing 1

Aims To understand the purpose of testing To understand the different test strategies To explore the four types of test data Have a understanding of Test plans and Test logs 2

Testing - Purpose The purpose of testing is not to demonstrate how solid your code is, it is to find the bugs. Testing is an art. No method always works, you must think about what the user may do, not what you would do. 3

Testing strategies White box testing –It is also know as open box/clear box testing –Deals with the internal workings of the system i.e. programming code - Loop testing. Black box testing –Involves testing without the knowledge of the internal workings of the system –If for any given input, we can predict the output, then the module passes the test

Testing strategies Black box testing AdvantagesDisadvantages Effective on larger systemsOnly a few inputs can be tested Test needs no knowledge of the details by which the system was constructed You can not test every combination Tests are done from the users point of viewHard to really test complicated parts of the system Can expose ambiguities Tests can be designed as soon as the specifications are complete

Testing – What should be tested? If a program is long then you can’t test all the possible routes through it (even something that is safety critical such as the flight control software of the Airbus was not fully tested). 6

Testing – What should be tested? TEST DATA There are four different conditions that testers use to test programs, these are: Normal – valid data that the program should handle correctly Extreme – also valid data, but at the limit in terms of size/ range (tests the boundaries) Erroneous – totally invalid data i.e. text into a numeric field Wrong – invalid data that is clearly incorrect 7

Examples – of each condition For this example, a program only allows dates between (inclusive) 01/01/2007 to 01/01/2008 Normal – 15/03/2007 Extreme – 01/01/2007, 02/01/2007, 31/12/2006 Erroneous – 01 / March / 07 Wrong – 38/12/2007 8

Test Plan A test plan is used to provide a basis for specifying tests that are to be carried out during the development of a program. A test plan if carried out correctly provides valuable evidence that the system (or sub systems) performs as it should. A test plan should contain normal, extreme, erroneous and wrong test data. 9

What does a Test plan consist of? 10

Test log A test log is used to prove that all the tests carried out in the test plan were carried out. Below shows an example of a test that would be shown in the test log. Test number 1 (this refers to the test No in the test plan) 11

Conclusion We have covered the following aims To understand the purpose of testing To understand the different test strategies To explore the four types of test data Have a understanding of Test plans and Test logs 12