Types of software Testing

There are many types of testing. Generally it is classified as White box testing and Black box testing.


White Box Testing
Testing of a function with knowing internal structure of the program. Also known as glass box, structural, clear box and open box testing. A software testing technique whereby explicit knowledge of the internal workings of the item being tested are used to select the test data. Unlike black box testing, white box testing uses specific knowledge of programming code to examine outputs. The test is accurate only if the tester knows what the program is supposed to do. He or she can then see if the program diverges from its intended goal. White box testing does not account for errors caused by omission, and all visible code must also be readable.

Black Box Testing
Testing of a function without knowing internal structure of the program. Black-box and white-box are test design methods. Black-box test design treats the system as a "black-box", so it doesn't explicitly use knowledge of the internal structure. Black-box test design is usually described as focusing on testing functional requirements. Synonyms for black-box include: behavioral, functional, opaque-box, and closed-box. White-box test design allows one to peek inside the "box", and it focuses specifically on using internal knowledge of the software to guide the selection of test data. Synonyms for white-box include: structural, glass-box and clear-box. While black-box and white-box are terms that are still in popular use, many people prefer the terms "behavioral" and "structural". Behavioral test design is slightly different from black-box test design because the use of internal knowledge isn't strictly forbidden, but it's still discouraged. In practice, it hasn't proven useful to use a single test design method. One has to use a mixture of different methods so that they aren't hindered by the limitations of a particular one. Some call this "gray-box" or "translucent-box" test design, but others wish we'd stop talking about boxes altogether.


Black Box Testing Types






Unit Testing

In computer programming, a unit test is a method of testing the correctness of a particular module of source code. The idea is to write test cases for every non-trivial function or method in the module so that each test case is separate from the others if possible. It is the first test in the development process. The source code is normally divided into modules, which in turn are divided into smaller units called units. These units have specific behavior. The test done on these units of code is called unit test. It is important to realize that unit-testing will not catch every error in the program. By definition, it only tests the functionality of the units themselves. Therefore, it will not catch integration errors, performance problems and any other system-wide issues. In addition, it may not be trivial to anticipate all special cases of input the program unit under study may receive in reality. Unit testing is only effective if it is used in conjunction with other software testing activities.

Integration Testing Integration testing is the phase of software testing in which individual software modules are combined and tested as a group. It follows unit testing and precedes system testing. It takes as its input modules that have been checked out by unit testing, groups them in larger aggregates, applies tests defined in an Integration test plan to those aggregates, and delivers as its output the integrated system ready for system testing. The overall idea, is the "building block" approach in which verified assemblages are added to a verified base which is then used to support the Integration testing of further assemblages. System Testing

System testing is a type of testing where the testing environment is same as that of the production environment. It can be done only when all the integrated modules work fine without bugs. As a rule, System testing takes, as its input, all of the "integrated" software components that have successfully passed Integration testing and also the software system itself integrated with any applicable hardware systems. The purpose of Integration testing is to detect any inconsistencies between the software units that are integrated together called assemblages or between any of the assemblages and hardware. System testing is more of a limiting type of testing, where it seeks to detect both defects within the "inter-assemblages" and also the system as a whole.
Performance Testing Performance testing is a testing that is performed to determine how fast some aspect of a system performs under a particular workload. Performance testing can serve different purposes. It can demonstrate that the system meets performance criteria. It can compare two systems to find which performs better. Or it can measure what parts of the system or workload cause the system to perform badly. In the diagnostic case, software engineers use performance tools such as Mercury Load runner, Empirix e-load to measure what parts of a device or software contribute most to the poor performance or to establish throughput levels (and thresholds) for maintained acceptable response time. In performance testing, it is often crucial (and often difficult to arrange) for the test conditions to be similar to the expected actual use. Performance testing technology employs one or more PCs to act as injectors – each emulating the presence or numbers of users and each running an automated sequence of interactions (recorded as a script, or as a series of scripts to emulate different types of user interaction) with the host whose performance is being tested. Usually, a separate PC acts as a test conductor, coordinating and gathering metrics from each of the injectors and collating performance data for reporting purposes. The usual sequence is to ramp up the load – starting with a small number of virtual users and increasing the number over a period to some maximum. Performance testing is of various types:

1. Load Testing: It is the testing of an application by applying varying loads. The intention is to find the breaking point of the application where it crashes. The load is applied in multiple factors.

2. Stress Testing: It is a form of testing that is used to determine the stability of a given system or entity. It involves testing beyond normal operational capacity, often to a breaking point, in order to observe the results. For example, a web server may be stress tested using scripts, bots, and various denial of service tools to observe the performance of a web site during peak loads. Stress testing a subset of load testing.

3. Soak Testing: It is a kind of testing where an application under test is put under load over a period of time say 48 to 72 hours to check the stability. Generally there can be memory overflow problem if the session connection is not cleaned from the memory.

4. Volume Testing: It is similar to stress testing but generally done for stand alone application where we check for the system by sending huge volume of data across the system. For example if we consider any banking applications, a back up is created for every 5 seconds to avoid crashing of the data. The data from one system is transferred to another system through an intermediate system which monitors the performance of the transfer and also the speed of transfer.