What design pattern should you use for your test automation project?

1 Linear Scripting

Linear scripting is the simplest and most straightforward design pattern for test automation. It involves writing your test cases as a sequence of steps, without any abstraction, modularity, or reusability. For example, you might write a test case like this:

# Test case: Log in as a user
Open browser
Go to login page
Enter username
Enter password
Click login button
Verify welcome message
Close browser        

Linear scripting is easy to write and understand, but it has many drawbacks. It is not scalable, maintainable, or flexible. If you need to change or update your test cases, you have to modify each script individually, which is time-consuming and error-prone. Also, if you have multiple test cases that share some steps, you have to repeat them in each script, which leads to code duplication and inconsistency. Linear scripting is only suitable for very simple and short-term test automation projects.

2 Modular Testing

Modular testing is a design pattern that improves the reusability and maintainability of your test automation project. It involves breaking down your test cases into smaller, independent modules that perform specific functions or actions. For example, you might create a module for logging in, a module for navigating to a page, a module for filling a form, and so on. Then, you can combine these modules to create different test cases, without writing the same code again. For example, you might write a test case like this:

# Test case: Log in as a user and fill a form
Call login module with username and password
Call navigate module with page name
Call fill form module with form data
Verify form submission        

Modular testing is more scalable, maintainable, and flexible than linear scripting. It reduces code duplication and inconsistency, and makes it easier to change or update your test cases. However, modular testing still has some limitations. It does not provide a clear separation of concerns between the test logic and the test data. Also, it does not handle complex dependencies or variations between test cases very well. Modular testing is suitable for medium-sized test automation projects that have some common functionality and data.

3 Data-Driven Testing

Data-driven testing is a design pattern that enhances the flexibility and efficiency of your test automation project. It involves separating the test logic from the test data, and storing the test data in an external source, such as a file, a database, or a spreadsheet. For example, you might store your login credentials, your page names, and your form data in a CSV file. Then, you can use the same test logic to execute multiple test cases with different data sets, without modifying the code. For example, you might write a test case like this:

# Test case: Log in as a user and fill a form with data from CSV file
Read data from CSV file
Call login module with data[username] and data[password]
Call navigate module with data[page name]
Call fill form module with data[form data]
Verify form submission        

Data-driven testing is more flexible and efficient than modular testing. It allows you to test multiple scenarios and variations with minimal code changes. It also makes it easier to manage and update your test data, and to reuse it across different test cases. However, data-driven testing still has some challenges. It does not provide a clear structure or hierarchy for your test cases. Also, it does not handle complex logic or conditions within your test cases very well. Data-driven testing is suitable for large test automation projects that have many scenarios and variations with different data sets.

4 Keyword-Driven Testing

Keyword-driven testing is a design pattern that improves the structure and readability of your test automation project. It involves defining keywords that represent the actions or functions of your application, and using them to write your test cases in a table format. For example, you might define keywords like LOGIN, NAVIGATE, FILL FORM, and VERIFY. Then, you can write your test cases like this:

# Test case: Log in as a user and fill a form
| Keyword   | Parameter 1 | Parameter 2 | Parameter 3 |
| LOGIN     | username    | password    |             |
| NAVIGATE  | page name   |             |             |
| FILL FORM | form data   |             |             |
| VERIFY    | submission  |             |             |        

Keyword-driven testing is more structured and readable than data-driven testing. It provides a clear hierarchy and organization for your test cases, and makes them easier to understand and communicate. It also allows you to handle complex logic or conditions within your test cases, by using keywords like IF, ELSE, LOOP, and so on. However, keyword-driven testing requires more effort and expertise to implement and maintain. You have to define and map your keywords to your modules, and ensure that they are consistent and accurate. You also have to create and manage your test tables, and ensure that they are aligned with your keywords and modules. Keyword-driven testing is suitable for complex test automation projects that require high-level abstraction and readability.

5 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?