Unit Test

Unit testing is a software verification and validation method in which a programmer tests if individual units of source code are fit for use. A unit is the smallest testable part of an application. In procedural programming a unit may be an individual function or procedure.

Unit tests are typically written and run by software developers to ensure that code meets its design and behaves as intended.

The primary goal of unit testing is to take the smallest piece of testable software in the application, isolate it from the remainder of the code, and determine whether it behaves exactly as you expect. Each unit is tested separately before integrating them into modules to test the interfaces between modules. Unit testing has proven its value in that a large percentage of defects are identified during its use.

The most common approach to unit testing requires drivers and stubs to be written. The driver simulates a calling unit and the stub simulates a called unit. The investment of developer time in this activity sometimes results in demoting unit testing to a lower level of priority and that is almost always a mistake. Even though the drivers and stubs cost time and money, unit testing provides some undeniable advantages. It allows for automation of the testing process, reduces difficulties of discovering errors contained in more complex pieces of the application, and test coverage is often enhanced because attention is given to each unit.


For example, if you have two units and decide it would be more cost effective to glue them together and initially test them as an integrated unit, an error could occur in a variety of places:
1) Is the error due to a defect in unit 1?
2) Is the error due to a defect in unit 2?
3) Is the error due to defects in both units?
4) Is the error due to a defect in the interface between the units?
5) Is the error due to a defect in the test?
Finding the error (or errors) in the integrated module is much more complicated than first isolating the units, testing each, then integrating them and testing the whole.

Selenium

Selenium is a portable software testing framework for web applications.

Selenium provides a record/playback tool for authoring tests without learning a test scripting language. Selenium provides a test domain specific language (DSL) to write tests in a number of popular programming languages, including Java, Ruby, Groovy, Python, PHP, and Perl. Test playback is possible in most modern web browsers. Selenium deploys on Windows, Linux, and Macintosh platforms.

It is open source software, released under the Apache 2.0 license and can be downloaded and used without charge. The latest side project is Selenium Grid, which provides a hub allowing the running of multiple Selenium tests concurrently on any number of local or remote systems, thus minimizing test execution time.

Bug Tracking System

A bug tracking system is a software application that is designed to help quality assurance and programmers keep track of reported software bugs in their work. It may be regarded as a sort of issue tracking system.

Many bug-tracking systems, such as those used by most open source software projects, allow users to enter bug reports directly. Other systems are used only internally in a company or organization doing software development. Typically bug tracking systems are integrated with other software project management applications.

Having a bug tracking system is extremely valuable in software development, and they are used extensively by companies developing software products.

Defect Prevention

The objective of defect prevention is to identify the defects and take corrective action to ensure they are not repeated over subsequent iterative cycles. Defect prevention can be implemented by preparing an action plan to minimize or eliminate defects, generating defect metrics, defining corrective action and producing an analysis of the root causes of the defects.

Defect prevention can be accomplished by actioning the following steps:

1) Calculate defect data with periodic reviews using test logs from the execution phase: this data should be used to segregate and classify defects by root causes. This produces defect metrics highlighting the most prolific problem areas;
2) Identify improvement strategies;
3) Escalate issues to senior management or customer where necessary;
4) Draw up an action plan to address outstanding defects and improve development process.This should be reviewed regularly for effectiveness and modified should it prove to be ineffective.
5) Undertake periodic peer reviews to verify that the action plans are being adhered to;
6) Produce regular reports on defects by age. If the defect age for a particular defect is high and the severity is sufficient to cause concern, focussed action needs to be taken to resolve it.
7) Classify defects into categories such as critical defects, functional defects, and cosmetic defects.

Defect Tracking

Defect tracking is the process of finding defects in a product (by inspection, testing, or recording feedback from customers), and making new versions of the product that fix the defects. Defect tracking is important in software engineering as complex software systems typically have tens or hundreds or thousands of defects: managing, evaluating and prioritizing these defects is a difficult task: defect tracking systems are computer database systems that store defects and help people to manage them.

Installation Testing

Installation testing is a kind of quality assurance work in the software industry that focuses on what customers will need to do to install and set up the new software successfully. The testing process may involve full, partial or upgrades install/uninstall processes.

This testing is typically done by the software testing engineer in conjunction with the configuration manager. Implementation testing is usually defined as testing which places a compiled version of code into the testing or pre-production environment, from which it may or may not progress into production. This generally takes place outside of the software development environment to limit code corruption from other future releases which may reside on the development network.

OR

Installation testing (in software engineering) can simply be defined as any testing that occurs outside of the development environment. Such testing will frequently occur on the computer system the software product will eventually be installed on.

Whilst the ideal installation might simply appear to be to run a setup program, the generation of that setup program itself and its efficacy in a variety of machine and operating system environments can require extensive testing before it can be used with confidence.

In distributed systems, particularly where software is to be released into an already live target environment (such as an operational web site) installation (or deployment as it is sometimes called) can involve database schema changes as well as the installation of new software. Deployment plans in such circumstances may include back-out procedures whose use is intended to roll the target environment back in the event that the deployment is unsuccessful. Ideally, the deployment plan itself should be tested in an environment that is a replica of the live environment. A factor that can increase the organisational requirements of such an exercise is the need to synchronize the data in the test deployment environment with that in the live environment with minimum disruption to live operation.

Stochastic Testing

Stochastic testing is the same as "monkey testing", but stochastic testing is a lot more technical sounding name for the same testing process.

Stochastic testing is black box testing, random testing, performed by automated testing tools. Stochastic testing is a series of random tests over time. The software under test typically passes the individual tests, but our goal is to see if it can pass a large number of individual tests.

What is the NUnit Framework?

NUnit framework is port of JUnit framework from java and Extreme Programming (XP).

This is an open source product. You can download it from http://www.nunit.org. The NUnit framework is developed from ground up to make use of .NET framework functionalities. It uses an Attribute based programming model. It loads test assemblies in separate application domain hence we can test an application without restarting the NUnit test tools. The NUnit further watches a file/assembly change events and reload it as soon as they are changed. With these features in hand a developer can perform develop and test cycles sides by side.

We should also understand what NUnit Framework is not:
1)It is not Automated GUI tester.
2)It is not a scripting language, all test are written in .NET supported language e.g. C#, VC, VB.NET, J# etc.
3)It is not a benchmark tool.
4)Passing the entire unit test suite does not mean software is production ready.

What Is NUnit?

NUnit is a unit-testing framework for all .Net languages.

Initially ported from JUnit, the current production release, version 2.5, is the sixth major release of this xUnit based unit testing tool for Microsoft .NET. It is written entirely in C# and has been completely redesigned to take advantage of many .NET language features, for example custom attributes and other reflection related capabilities. NUnit brings xUnit to all .NET languages.