Fundamentals of Software Testing - Chapter 1

Chapter 1: Fundamentals Of Software Testing 1 Software Testing definition ▪ Software Testing is the process of exercising or evaluating a system or system component by manual or automated means to verify that it satisfies specified requirements o...

Chapter 1: Fundamentals Of Software Testing 1 Software Testing definition ▪ Software Testing is the process of exercising or evaluating a system or system component by manual or automated means to verify that it satisfies specified requirements or to identify differences between expected and actual results. 2 Error, Fault and Failure… ▪ An Error occurs in the process of writing a program. ▪ A fault is the manifestation of one or more errors. The fault is also known as bug and defect. 3 ▪ A failure occurs when a faulty piece of code is Some Testing Principles ▪ Testing starts during the requirements phase. ▪ Program testing can be used to show the presence of Errors, but never their absence. ▪ The programmer shall not be the tester. ▪ A test cycle is often guided by a test plan. 4 We need professional testers(1) ▪ Developers can’t find their own defects….Why? ▪ Because: ▫ They have no motivation for testing. ▫ They have no skills for testing. ▫ They have no time for testing. 5 We need professional testers(2) ▪ Testers have the tester’s mindset: 1. Goal is to find Errors, Faults and Failures 2. Get the Errors fixed together with developers. 3. Testers are independent verifiers; they can test the software from the customer’s or user’s viewpoint. 4. Testers have the skills, tools, and experience. 6 Levels or Phases of Testing during Development Integration Component Unit Testing Testing Testing User System Integration Acceptance Testing Testing Testing 7 User Based Testing ▪ Alpha: actual end-user testing performed within the development environment. ▪ Beta: end-user testing performed within the user environment prior to general release. ▪ Acceptance: formal testing conducted to enable the customer to determine whether or not to accept the system (acceptance criteria may be defined in a contract) 8 Other Types of Testing During Maintenance ▪ Regression: testing to detect problems caused by the adverse effects of program change. 9 Test Oracle and Test Bed ▪ Test Oracle: is a document, or a piece of SW that allows testers to determine whether a test has been passed or failed. ▪ Test Bed: is an environment that contains all the HW and SW needed to test a software component or SW system as simulators, emulators memory checkers, hardware probes, SW tools, and all other needed items to support execution of the tests. 10 Static Testing ▪ Static testing is a technique in which the software is tested without executing the code. It has two parts as listed below: ▪ Review - Typically used to find and eliminate errors or ambiguities in documents such as requirements, design, test cases, etc. ▫ Walkthrough ▫ Inspections ▪ Static analysis - The code written by developers are analysed (usually by tools) for structural defects 11 that may lead to defects. Test case/data ▪ A test case is a pair consisting of test data to be input to the program and the expected output. The test data is a set of values, one for each input variable. ▪ Test cases must be written for invalid and unexpected, as well as valid and expected, input conditions. ▪ A test set is a collection of zero or more test cases. ▫ Sample test case for sort: ▫ Test data: