What is Test Driven Development?
Software testing plays a vital role in the life cycle of software development. It is imperative to identify bugs and errors during software development and increase the quality of the product. Therefore, one must focus on software testing. There are many approaches and Test Driven approach is one of them.
Test Driven Development is a key practice for extreme programming; it suggests that the code is developed or changed exclusively by the unit testing. Test Driven Development (TDD) is a software-driven process which includes test-first development. It means that the developer first writes a fully automated test case before writing the production code to fulfill that test and refactoring.
How TDD Works?
- Firstly, add a test.
- Run all the tests and see if any new test fails.
- Update the code to make it pass the new tests.
- Rerun the test and if they fail then refactor again and repeat.
Benefits of Test Driven Development
- It gives a way to think through one's requirements or design before developer writes functional code.
- It is a programming technique that enables the developer to take a small step during building software.
- It is more productive as compared attempting to code in giant steps.
- Consider an example, developer write some code, then compile it, and then test it, maybe there are chances of failure. In this case, it becomes easy to find and fix those defects if a developer had written two new lines of code than a thousand.
A Test Driven Development is – The most efficient and attractive way to proceed in smaller and smaller steps.
Following Test Driven Development means –
- Fewer Bugs.
- Higher quality software.
- Focus on single functionality at a given point in time.
Why Test Driven Development Matters?
- Requirements – Drive out requirement issues early (more focus on requirements in depth).
- Rapid Feedback – Many small changes Vs. One significant change.
- Values Refactoring – Refactor often to lower impact and risk.
- Design to Test – Testing driving good design practice.
- Tests as information – Documenting decisions and assumptions.
Test Driven Development helps the programmer in several ways, such as –
- Improve the code.
- Side by side, increasing the programmer’s productivity.
Using Test Driven Development concept in one's programming skills –
- Will save developer's time which is getting wasted for rework.
- Able to identify the error/problem quicker and faster.
- The programmer will be able to write small classes which will be focused only on a single functionality instead of writing the big classes.
- Whenever the code base gets more prominent, it becomes tough to change and debug the code. Moreover, there is a high chance of the code being messed up.
But, if developers are using Test Driven Development technique –
- Means developers have automated tests.
- Writing the test cases for the program which is a safe side for the programmers.
- It becomes easy to view what the error is, where it is and how it is paralyzing one's code.
Best Practices to Adopt Test Driven Development
- Road Map – One of the best practice is to clear out with thought and further break it down into the test case. Follow the red-green approach to build the test case. The first step is to create the red test and after exposing all the problem related to code, make some changes and make it a green test.
- Implementation – It is essential to implement both source code and test case separately. For both implementation and testing, there should be two directories. In every programming language, there should be different packages for both. Consider an example, in the case of Java “src/main/java” is used for implementation and on the other hand “src/test/java” is used for testing.
- Structure – Structure for writing test cases should be correct. It is common practice to write the test class with the same name used in production/implementation class, but there should be a change in the suffix. Consider an example; if the implementation/production class is “Student,” then the test class should be “StudentTest.” And similarly in case of methods, test methods are written with the same name as of production methods, but there should be a change in the prefix, like if the method name is “display student name,” then in testing it should be “testDisplayStudentName.”
Top Test Driven Development Tools
There are many tools available for testing and improving the overall design and implementation of the software system. Some of the most common testing tools are listed below –
JUnit for Unit Tests
Junit is a unit testing framework designed for Java programming language. Unit tests are the smallest elements in the test automation process. With the help of unit tests, the developer can check the business logic of any class. So JUnit plays a vital role in the development of a test-driven development framework. It is one of the families of unit testing frameworks which is collectively known as the xUnit that originated with SUnit.
JMeter for Load/Performance Testing
Apache JMeter may be used to test performance both on static and dynamic resources, Dynamic Web applications (Mainly for Load/Performance testing). It is used to simulate a heavy load on a server, group of servers, network or object to test its strength or to analyze overall performance under different load types.
Features of Apache JMeter –
Ability to load and performs tests on many different applications/server/protocol types, some of them are listed below –
- Web – HTTP, HTTPS (Java, NodeJS, PHP, ASP.NET)
- SOAP/REST Webservices
- Database via JDBC
- Message-oriented middleware (MOM) via JMS
- Mail – SMTP(S), POP3(S) and IMAP(S)
- Native commands or shell scripts
- Java Objects
Mockito for Rest API Testing
Mockito designed as an open source testing framework for Java which is available under an MIT License. Mockito allows programmers to create and test double objects (mock objects) in automated unit tests for Test-driven Development (TDD). In simple words, Mockito is a framework that developers specifically use to write certain kind of tests efficiently.
There are also many other tools and frameworks available. It depends on the type of programming language, according to the language developer can pick up an appropriate tool and framework for Test Driven Development.