Skip to main content

Mastering Test Automation with SOLID Principles

Test Automation solid principles-ACCELQ
Posted On: 5 June 2023

If there is one thing that's constant in today's world, it is change. And that's what any software product goes through. But as the product goes through a series of updates and changes, it becomes increasingly complex to develop and test. As a result, development teams need to fall back on SOLID principles to create an effective quality strategy.

What are SOLID Principles?

SOLID design principles are a set of norms that help reduce dependencies in the software design process.

Intended to make designs easier to understand, maintain, and scale, SOLID principles allow developers to make changes to one part of the code without impacting the performance of other parts.

What are Solid Principles-ACCELQ

In the current volatile business environment, every developer should know and utilize these five SOLID principles:

1. Single Responsibility Principle (SRP)

SRP states that any class, module, component, or microservice should have only one responsibility or solve only one problem for any one part of the software's functionality. The principle makes it easy to develop, test, and maintain code while avoiding the unforeseen side effects of future changes.

For example, the checkout process in an e-commerce application will have many features such as order summary, shipping address, payment mode, payment details, etc. Instead of developing each feature as a separate entity, teams can use SRP to regroup the responsibilities of checkout into smaller entities. Such separation of concerns ensures low-level changes do not impact high-level business logic.

2. Open Closed Principle (OCP)

This principle allows software entities such as classes, modules, and functions to be easily extended but not modified. This means teams can extend a class's behavior without modifying it. OCP makes it easy for teams to write code that doesn't have to be modified every time the requirements change. By writing code that is easy to maintain and revise, teams can easily add additional functionality using abstractions.

Consider an e-commerce company that wants to introduce a new mode of payment. OCP allows the development team to add a new "payment" class without modifying the underlying code.

3. Liskov Substitution Principle (LSP)

Named after Barbara Liskov, who introduced this concept, LSP is simply an extension of the open-closed principle. It states that any derived class should allow for extending the base class without changing behavior. The principle helps avoid unexpected consequences of changes while eliminating the need to open a closed class for updates and extensions.

For instance, in an e-commerce payment scenario, customers can purchase using their credit card or a digital wallet. Under normal circumstances, the code will throw an exception if a user uses the card option. Using LSP, developers can add another class for payment and structure the class hierarchy in a way that does not break the application.

4. Interface Segregation Principle (ISP)

The general idea of an ISP is to have several smaller interfaces instead of one big, general-purpose interface. Such fine-grained client-specific interfaces allow developers to start with an existing interface and add new methods as needed. It also ensures clients are not forced to implement interfaces they do not use.

Consider an e-commerce company that has a web client for placing orders and an admin client for configuring stores and products. Keeping these interfaces isolated enables easier development of new features and changes. It also improves the understandability and maintainability of specific interfaces while allowing them to evolve separately over time.

5. Dependency Inversion Principle (DIP)

This design principle offers an easy way to decouple software modules. By empowering developers to focus on abstractions and not concretions, DIP ensures high-level modules do not depend upon low-level modules. DIP makes code more flexible, agile, and reusable when done right.

An e-commerce company that wants to change its payment gateway from PayPal to Apple Pay would need to make several changes to the underlying code. Teams would also have to test everything from scratch again. Using DIP, they can create an intermediate layer and wrap it around the payment gateway service. By abstracting the payment gateways, developers can make the required switch to Apple Pay – without impacting the code.

Do more with Test Automation

Discover more ways to add ‘low-code no-code‘ test automation in your workflows

What are the Benefits of Applying SOLID Principles to Test Automation?

In essence, embracing SOLID principles makes it easier for software developers to dodge common design issues and develop adaptive agile products. They also help strengthen code and improve its overall readability, maintainability, and testability. Applying these design principles to test automation:

  • Helps reduce dependencies in code, improving modularity, testability, and maintainability.
  • Makes code easier to understand, extend, and scale, allowing organizations to address evolving business and customer requirements quickly.
  • Improves design and code quality and ensures a single change or update does not break the whole application.
  • Improves test coverage and execution by making the process of debugging simple and straightforward.
  • Reduces maintenance burden and allows developers to refactor code quickly and effortlessly.

How to Incorporate SOLID Principles in Test Automation

Incorporating SOLID design principles in software engineering is a great way to make software easier to maintain, test, and extend. Although SOLID design principles deliver several benefits, how, when, and if you should implement them depends on your unique use case. Just following these principles is not a cure for all your design issues.

If you want to avoid your test automation process from becoming fragile and hard to maintain or extend, here are some tips to follow:

  • When you want to refactor code, make sure to create interfaces and implement classes.
  • Create small role-specific interfaces rather than one big general-purpose interface.
  • Once the interfaces have been defined and classes implemented, introduce additional classes as needed to extend your code.
  • Instead of changing existing functionality, just add another class to initiate the additional client through its driver.
  • Invest in tools that help you keep a check on your design process and provide alerts when things go off track.

SOLID Principles for Solid Products

If you want to write high-performing, efficient code that can be maintained and scaled quickly, you must embrace SOLID design principles in software engineering. Although SOLID principles make code easy to maintain and extend, they also tend to make the codebase highly complex. Embracing SOLID design principles' tips and best practices in test automation can help reduce the complexity of code, streamline the design process, and avoid headaches down the road.

Interested in learning more about how SOLID principles can help you master test automation? Talk to our experts today!


Geosley Andrades

Director, Product Evangelist at ACCELQ.

Geosley is a Test Automation Evangelist and Community builder at ACCELQ. Being passionate about continuous learning, Geosley helps ACCELQ with innovative solutions to transform test automation to be simpler, more reliable, and sustainable for the real world.

Related Posts

BlogTest Automation
28 October 2020

5 tips for a stable element ID in Selenium automation

Element Identification is a crucial step in achieving automated test interaction in Selenium against browser-based applications. Poor element identification design results in failure to identify elements at run time thus…
Shift-left testing in agile-ACCELQBlogTest AutomationTesting
22 June 2022

Best Practices for Shift-Left Testing in Agile

Shift left testing is a mainstay software testing strategy today, especially for enterprises following agile methodologies in software development. The shift left methodology has several takers from various industries that…

Get started on your Codeless Test Automation journey

Talk to ACCELQ Team and see how you can get started.

Close Menu