Test Driven Software Development: A Process for Increasing Software Quality and Decreasing Development Time.

The process of software development is always changing, and with that comes new ways to increase quality. One way to do this is through test-driven development (TDD). This article will give you an overview of what TDD is and how it can be applied in your company.

TDD relies on the idea that if we know what our customers want before we start developing a product or service then we can deliver it quicker and with more efficiency than ever before.

Introduction

Kent Black is the creator of the term ‘TDD’ and he is also credited for creating an easy way to understand TDD. His definition states that “TDD is a process where you write your tests before you implement the code it’s testing”.

The first step-in test-driven software development process starts with writing out what our test cases will be, by starting off with simple functional requirements. Then, we write out our tests to cover these requirements before writing any code that will eventually execute the features within them.

The next step in this process is to implement the test case’s feature making sure it passes all of its tests. Once you have done this your product should be ready for production testing where more complex scenarios are tested against your product.

Lifecycle

1.Think and create the test cases. It starts with thinking of what your functional requirements are and ensuring they will be tested. Write the test case, starting with simple scenarios for each requirement. After creating a specific set of tests to cover all product features, start writing code that satisfies those rules and makes sure it is fully covered by tests before you move forward.

2.Run these tests. At this stage since the functionality has not been achieved yet the code is expected to fail. Test failure shows us that new code is actually needed for the desired features to function and validates our assumptions that the test harness is indeed working.

3.Design simplest code that achieves the test functionality. Create the required code that makes the tests pass, ensuring it’s fully covered by tests before moving forward. Any code that does not pass the tests must be revised until a successful pass is achieved.

While doing this you should also be refactoring your product to ensure reusable features and keep everything organized so it doesn’t become too complex later on in its usage which is the next step.

4.Refactor the code Code is refactored to create a good design and it is expected to be easier to maintain. Refactoring should not change the functionality of existing code, but instead make its purpose clearer.

The final stage in TDD lifecycle focuses on production testing which ensures all functional requirements are satisfied by your product before allowing customers access to use them. This also helps with any future updates that are made to the software.

Test Driven Development is a good way of increasing quality while decreasing development time, but it does require some planning before you get started so make sure you have all your requirements ready and documented.

Best Practices to follow

1. Create test cases before writing any code to ensure all required features are covered by the tests, these should be written in a specific order which is usually based on priority or functional requirements so that they can flow smoothly when being executed at their designated times.
2. The structure of your test case needs to have set up, execution, validation, and cleanup.
3. Each test case should have a specific purpose to fulfill so that it can be executed in isolation without any other tests interfering with its results. Once the test is done executing all of its features you need to clean up after yourself before moving on to your next set of functional requirements for this software project.
4. Write simple test cases to ensure the product is functional enough before moving on, this will allow you to do more complex testing later. You can also refactor your code as needed during initial development so that it meets current standards but does not affect its core functionality.

Anti-patterns to avoid

Dependencies between test cases should be avoided as interdependent tests can cause cascading false negatives .

Tests should be independent of one another so that they can run in isolation without any side effects, this will allow for a more clear and concise result as well as the ability to reproduce them regardless of their execution order.

In some cases test suites need to be ordered by priority or functional requirements but these shouldn’t have dependencies on each other.

Slow running tests should be removed or split up. This is a good practice to follow because if your test suite takes too long to execute it could affect other tests in the process which then causes false negatives due to the order they are ran that may not be relevant for this specific project.

Benefits of Test-Driven Software Development.

The process of designing a program using test-driven development includes more than simply validating that it is correct. It may also influence the design of a program. The process starts with thinking about how clients will utilize the functionality (in the first scenario, the test cases). As a result, before getting down to business, the programmer should think about how the program will be used. This may result in a design that is more modular, or perhaps just easier to use.

TDD may lead to more modularized, flexible, and extensible code. Because the process encourages developers to conceive of the software in terms of small components that can be created and tested independently and later integrated together, this effect is frequently seen.

Because no more code is written than is required to pass a failing test case, automated tests tend to check every code path. To add an else branch to an existing if statement in TDD, for example, a developer must first create a failing test case that encourages the branch. As a result, automated tests resulting from TDD are typically very comprehensive.

Some Pitfalls of TDD.

In a test-driven development environment, unit tests are generally created by the person who is developing the code being tested. As a result, the tests may share blind spots with the code: if, for example, a developer does not realize that certain input parameters must be checked, both the test and the code will fail to verify them.

Another scenario where this can affect the final results is when a developer neglects to update an existing test for code refactoring.

Test-driven development may not be suitable in all situations, such as those involving hardware and software integration testing (frequently known as “Regression Testing”), where it’s necessary to know what was happening with the application before new changes were integrated.

Another pitfall of test-driven development is that it does not address the issue of how to write tests for legacy code, or existing production systems where changes are difficult and expensive (and which might even contain secret information). TDD encourages developers to start with a failing test case, but in such cases they often do not have the luxury of writing test cases that fail.

Tests are time-consuming to create and maintain. If the test suite grows out of control, it might take a long time for each test to execute. As a consequence, developers may opt not to run all checks in order to focus on certain aspects of the system.

Conclusion

In sum, test-driven development is a good practice to follow in order to limit the amount of defects being introduced into a code base. When used properly it can lead to higher software quality and less development time overall, however there are certain situations where TDD is not suitable for use.

In cases where full functional tests are required to determine success or failure, test-driven development does not adequately verify functionality.

Examples are User interfaces, programs that work with databases, and others that require specific network configurations.

TDD advocates that software be split into smaller components and that each component has as little code as possible, with the most logic being placed in testable library code using fakes and mocks to simulate the real world.

Thanks for reading through the article. I hope it has given you some insights into the Test-Driven Software Development process. What has been your experience with TDD? I’d love to hear