What makes a good test script? And how do you evaluate appropriate tools and languages? Here's what software developers and testers need to know to make test automation part of their process.
Maybe you're interested in automation test scripts because you've been told you need to write them, or maybe you just want to understand what automation is all about. Either way, let's look at what automated test scripts are, why you'd want to use them and some best practices for their creation.
What are automation test scripts?
In general, a test script is a set of instructions that describes an application's state, some actions and expected results from the actions performed. Ideally, a test script is written well enough to be repeatable by anyone who can read the script. A good test script should follow the Arrange, Act and Assert testing paradigm, which calls for a setup, an action and a validation or verification of some result.
An automated test script is the next level, where the script programmatically performs the setup and validation all on its own. Turning your test script into an automated test script can save time, reduce error and serve as documentation for your software.
Automation requires tooling
To start automating, we'll need tools. Many types of automated testing tools provide many types of testing. To begin, you need to decide what are you trying to test.
A classic automated test script tests at the level of an application's user interface, but it could also test the API, database or any other part of the system with which your tool interacts. For example, Postman and similar automation tools are ideal for testing API-level functionality but can't test the user interface. On the other hand, record-and-playback tools such as Selenium IDE are good choices for testing the UI, but you would not ask it to test APIs.
The Python programming language is much more general and has built-in extensions to allow for testing at the user interface level, in conjunction with Selenium, or at the API level with a package called requests.
The tradeoff with these tools is the complexity and learning curve. It won't take much time to learn how to use Selenium IDE and Postman, because there is less functionality to understand. With prior knowledge of a programming language, Python is easy to understand; it will take much longer to learn without any programming language experience. Choose a tool that matches your experience level and is best suited for the type of testing you want to do.
Automate effectively
When writing automation test scripts, consider some basic test design concepts that will help keep your tests simple and reusable.
Try to write small tests that can be independently executed. Smaller tests make it easier to debug an application, since there are fewer possibilities for failure. Coupling one test to another makes for a brittle test suite that can be doomed by the smallest interruption.
Automated test scripts are your ticket to quicker, more accurate tests.
Small tests can be extended or reused as modules by larger tests, which reduces the amount of maintenance needed to update tests for application changes. Make sure to take advantage of your automated testing tool's features. For example, Selenium IDE allows one test script to run another, which makes your test scripts more modular and maintainable.
When writing test scripts with programming languages, ensure that your test failures are useful. Clear, actionable test results mean testers can file more descriptive bugs and developers can quickly remediate those bugs. Many tools offer this, but if you're writing your own automated test scripts with a programming language, make sure your error messages are descriptive enough.
Automated test scripts are your ticket to quicker, more accurate tests. But automating too much can lead to more work than reward. Features that have frequently changing requirements are poor candidates for automation, as the test will need to be adjusted every time the feature is updated.
Always keep in mind the use case for your automated test script and the planned frequency. A test that's executed only rarely may be more efficient with manual methods, which require less initial work or time-consuming, tedious test maintenance.
To create an automated test script, find a manual test case that is often executed for a feature that is unlikely to change. Then, look for tools that can support the steps executed in the test case. Tool choice depends heavily on the type of application you're testing
Explore different options and develop your chosen manual test case as a proof of concept using various tools.
Test automation scripts can be powerful. They offer a greater level of efficiency than manual testing. If not used carefully, though, they can create more trouble than they are worth. Follow best practices to keep your tests clean, quick and maintainable.
