What are the best practices for using variables in keywords?

1 Use consistent naming conventions

One of the first things you should do when using variables in keywords is to follow a consistent naming convention. This will help you avoid typos, conflicts, and ambiguity, and make your keywords more readable and maintainable. Robot Framework supports three types of variables: scalar, list, and dictionary, and each has a different syntax for declaration and usage. You should use the recommended prefixes for each type: ${} for scalar, @{} for list, and &{} for dictionary. Additionally, you should use meaningful and descriptive names for your variables, and avoid using reserved or built-in variables.

2 Scope your variables appropriately

Another important aspect of using variables in keywords is to scope them appropriately. This means defining and using variables at the right level of your test automation project, depending on their purpose and scope. Robot Framework supports four levels of variable scope: global, suite, test, and local. Global variables are available throughout the project and are typically defined in resource files or command line options. Suite variables are available within a test suite and are typically defined in suite setup or settings. Test variables are available within a test case and are typically defined in test setup or settings. Local variables are available within a keyword and are typically defined in keyword arguments or variable assignments.

3 Use variable files and libraries

A third best practice for using variables in keywords is to use variable files and libraries. These are external files or modules that contain variable definitions or functions that return variables. They can help you organize and manage your variables, especially if you have a large number of them or need to generate them dynamically. You can import variable files and libraries in your settings section, and use them in your keywords as normal variables. Robot Framework supports various formats and languages for variable files and libraries, such as Python, YAML, JSON, and CSV.

5 Use variable expansion and evaluation

A fifth best practice for using variables in keywords is to use variable expansion and evaluation. Variable expansion means replacing a variable with its value within a string or another variable. This can help you create dynamic and complex values based on existing variables. For example, you can use variable expansion to construct a file path from a base directory and a file name variables. Variable evaluation means executing a Python expression or a keyword within a variable syntax, and using its return value as the variable value. This can help you perform calculations, conversions, or validations based on variables. For example, you can use variable evaluation to check if a variable is empty or not.

6 Use keyword return values

A sixth best practice for using variables in keywords is to use keyword return values. Keyword return values are the values that a keyword returns after its execution, and that can be assigned to variables for further use. This can help you capture and verify the output of your keywords, and pass it to other keywords or test cases. For example, you can use keyword return values to store the status code of an HTTP request, or the text of a web element. To use keyword return values, you need to use the [Return] setting in your keyword definition, and use the syntax ${var}= Keyword Name in your keyword or test case.

7 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?