Unit Testing and It’s Types

Software components or individual units are tested as part of a process called unit testing. Verifying that every program code unit operates as intended is the goal. Unit testing is carried out by developers when they are creating (coding) an application. Unit tests remove a portion of the code and confirm that it is correct. A singular function, technique, step, module, or item can all be considered a unit.

Unit testing is the initial testing stage carried out before integration testing in the SDLC, STLC, and V Models

 . One type of WhiteBox testing that the developer typically carries out is unit testing. However, in the real world, QA engineers also perform unit testing because of time constraints or developers’ aversion to testing.

Why Unit tests?

Software developers frequently attempt to save time by performing little unit testing, however, this is a misconception because improper unit testing results in expensive defect correction during system testing, integration testing, and even beta testing after the program is completed. This is why unit testing is crucial. Early on in the development process, proper unit testing can save money and time.
The following are the main justifications for unit testing in software engineering:

• Unit tests reduce expenses and aid in bug fixes early in the development cycle.
• It facilitates speedy change-making and aids in the developers’ understanding of the testing code base.
• Well-written unit tests act as project manuals.
• Unit tests facilitate the reuse of code. Transfer your tests and code to the new project. Make changes to the code until the tests are rerun.

Execution of Unit testing:

Developers write a certain amount of code to test a particular function in a software application to run unit tests. To test this function more thoroughly and identify any needless dependencies between it and other units, developers can also isolate it. This allows for the elimination of those dependencies. The UnitTest framework is typically used by developers to create automated test cases for unit testing.

There are two kinds of unit testing-

1. Manually
2. Automatically

Although it is usually automated, manual unit testing is still possible. Automation is favored, although software engineering does not favor one over the other. A manual unit test strategy could make use of a detailed instruction manual.

Regarding the automated method:

• To test a function, a developer creates a part of the application’s code. When the program is deployed, they would eventually remove the test code by commenting it out.
• An isolated version of the function might likewise be tested more thoroughly by a developer. This is a more comprehensive approach to unit testing, where code is copied and pasted into a testing environment instead of the source code. Code isolation facilitates the identification of superfluous relationships between the tested code and other product units or data areas. After that, these dependencies can be broken.
• To create automated test cases, programmers typically utilize the UnitTest Framework. To ensure that the code is valid, the developer incorporates criteria into the test using an automated framework. The framework logs failing test cases while they are being executed. Additionally, a lot of frameworks will automatically identify and summarise these unsuccessful test instances. The framework might stop testing more after a failure, depending on how serious it was.
• The Unit Testing workflow is–
  1.  Make test cases
  2. Examine and refine
  3. Beginning Point
  4. Carry Out Test Cases.

Techniques for Unit Testing:

Unit testing techniques can be broadly divided into three categories: Black box testing, which tests the user interface, input, and output; White box testing, which tests the software application’s functional behavior; and Grey box testing, which runs test suites, test methods, test cases, and performs risk analysis.
The following is a list of code coverage strategies used in unit testing:

1. Coverage of Statements
2. Coverage of Decisions
3. Coverage of Branches
4. Coverage of Conditions
5. Coverage of Finite State Machines

Tools for Unit Testing:

To help with unit testing in software testing, a number of automated unit test programs are available. Below are some instances that we shall give:

• Junit: For the Java programming language, Junit is a free testing tool. It offers claims to indicate the test methodology. This tool inserts test data into the piece of code before using it.
• NUnit: For all.net languages, NUnit is a popular unit-testing framework. It is an open-source program that enables manual script writing. Parallel data-driven test execution is supported.
• JMockit: It is an open-source tool for unit testing. This utility provides line and path metrics for code coverage. Mocking APIs with recording and verification syntax is supported. Line, Path, and Data coverage are all provided by this tool.
• EMMA: It is an open-source toolkit for reporting and analyzing Java programming code. Emma supports basic blocks, lines, and methods for coverage. Because it is Java-based, it can access the source code and doesn’t require any other libraries.
• PHPUnit: PHP programmers can use PHPUnit as a tool for unit testing. It takes what are known as units, or little segments of code, and tests each one independently. With the tool, developers can also assert that a system behaves in a particular way by using pre-define assertion methods.

These are but a handful of the unit testing tools that are out there. No matter what language you use, you can find a unit testing tool for your needs. There are many more, particularly for Java and C languages.

Benefits of Unit Testing:

• Developers can get a basic grasp of the unit API by looking at the unit tests, which provide information about what functionality is supplied by a unit and how to use it.
• Programmers can change code later on and ensure that the module continues to function correctly by using unit testing (also known as regression testing). In order to promptly identify and rectify any errors that may arise from changes, it is necessary to create test cases for each function and method.
• We can test portions of the project without having to wait for others to be finished because unit testing is modular.

The Drawbacks of Unit Testing:

• It is unrealistic to expect unit testing to find every bug in a program. Even with the simplest programs, it is not possible to analyze every conceivable path of execution.
• By definition, unit testing concentrates on a single code unit. Therefore, it is unable to detect system-wide or integration-level issues.