Introduction to Design Patterns
The Design patterns are defined as the best practices that a programmer must follow to amplify code reusability in a framework. The design pattern explains how to plan the test automation test ware to be useful and easy to maintain.
Discard many test automation projects due to the frameworks’ inability to cope with the growing codebases or test suites. Automation engineers should optimize their code to keep the maintenance cost low by using the best design procedures and code coverage of existing functionality for common or repeated operations.
The Advantages of Design Patterns in Automation Testing
The advantages of using the design patterns in our automation testing are as follows :
- Design Patterns saves time and effort
- It results in low maintenance cost
- Helps in code reusability
- It helps in enhancing reliability.
- Helping us to create a structured code that eases our process of automation.
- It helps in improving communication.
Choose a testing tool that can automate applications that you are planning to use — ideally, any application under test (AUT).
What are the types of Design Patterns in Test Automation?
Types of Design Patterns in test automation
Object Repository and Page Factory: Using Object Repository, a tester can keep all the objects employed in the script in one or more centralized locations rather than letting them be dispersed all over the test scripts.
Use Page factory to initialize the elements of the PageObject or instantiates the page object itself. If any object changes in UI, the tester needs to update the locator in the one centralized location instead of going through the whole code. It, therefore, saves a lot of time and effort.
Page Object: The Page Object Model is one of the most popular design patterns in test automation that reduces code duplication and improves test maintenance. A page object is the object-oriented class that works as an interface to your application page under test. To interact with the UI of the page, the tests then use the methods or functions of this page object class.
For example, let us consider a web application with a menu bar that leads to different modules with different features. Most of the automation scripts for this scenario would be navigating and clicking through various menu buttons. Now Imagine if the UI of the respective application is changed and menu buttons are relocated to different positions. This will ultimately result in test script failure as the scripts will not find the button’s locations to perform any actions.
To bring the scripts to the working mode, a QA Engineer will need to walk through the entire code to update the buttons’ locations. This is a time-consuming process. So to prevent this wastage of time, we use Page Object Model in our automation framework.
Architectural Design Patterns
Multilayered Architecture: In this design pattern, the test code is design is in the layer structure. The code is breakdown into layers on the basis of presentation logic, business logic, and data storage.
The topmost layer is the test case layer. The second layer comprises functional logic, and the third layer is for the UI automation tool, which interfaces with the AUT.
The multilayered architecture ensures low code maintenance costs.
Meta Frameworks: This design pattern provides a method for solving the problem of automating multiple pieces as part of a larger automation strategy. In this method, the automation engineers define independent utility classes that can generically use with any automation tool and reuseable with different automation projects.
This framework provides an abstraction layer that separates the automation pieces to execute and has their results display in a standard way. Such a solution increases reusability in case to test the different projects inside one organization.
An approach for developing small services each running in its process, and enables the continuous delivery/deployment of complex applications.
Design Patterns in Test implementation
Recorded Tests: In this design pattern, the user uses an automation tool to record his actions. For execution, the recorded script is played, and the results are observed. There are various tools available for recording our tests. One of such tools is Selenium IDE which allows us to record scripts in any language.
Modular Tests: This design pattern requires creating small, independent scripts representing the module, sections, and functionality of the AUT. Apply these short scripts in a hierarchical order to build large tests.
Data-Driven Automation Frameworks: It is a type of design pattern in which the data is stored in tables or spreadsheets. In this design pattern, the input data is usually stored in single or multiple data sources such as .xls, .xml, .csv, and databases.
This method is extremely important because testers often have multiple data sets for a single test. The creation of individual tests for each data set is a time-consuming process.
Keyword-driven Automation Framework: This design pattern’s primary function is to split the test Cases into four distinct parts. I.e., to split the test case into the following parts:
- Test Step
- The object of Test Step
- Action on Test Object
- Data for Test Object
This approach aims to separate the coding from the test case & test step to help a non-technical person understand the automation process.
Hybrid Driven Framework: This design pattern is a blend of both the Data-Driven and Keyword-Driven frameworks. It stores the keywords in a class file and maintains the test data either in the properties file or Excel files.
Manual testers frequently use, who lack knowledge of programming languages. They can directly create their test cases by focusing on the keywords, test data, and object repository without knowing the code.
Design patterns play a vital role in improvising our automation process. Every automation engineer should be familiar with these design patterns. But remember that one should use these design patterns only when there is a need. So it is important first to analyze which design patterns suit our test plan and then use them accordingly. Using design patterns uselessly can also lead to an increase in complexity.