Boa Constrictor is the .NET Screenplay Pattern. It helps you make better interactions for better test automation!
I originally created Boa Constrictor starting in 2018 as the cornerstone of PrecisionLender‘s end-to-end test automation project. In October 2020, my team and I released it as an open source project hosted on GitHub. Since then, the Boa Constrictor NuGet package has been downloaded over 44K times, and my team and I have shared the project through multiple conference talks and webinars. It’s awesome to see the project really take off!
Unfortunately, Boa Constrictor has had very little development over the past year. The latest release was version 2.0.0 in November 2021. What happened? Well, first, I left Q2 (the company that acquired PrecisionLender) to join Applitools, so I personally was not working on Boa Constrictor as part of my day job. Second, Boa Constrictor didn’t need much development. The core Screenplay Pattern was well-established, and the interactions for Selenium WebDriver and RestSharp were battle-hardened. Even though we made no new releases for a year, the project remained alive and well. The team at Q2 still uses Boa Constrictor as part of thousands of test iterations per day!
The time has now come for new development. Today, I’m excited to announce our plans for the next phase of Boa Constrictor! In this article, I’ll share the vision that the core contributors and I have for the project – tentatively casting it as “version 3.” We will also share a rough timeline for development.
Separate interaction packages
Currently, the Boa.Constrictor NuGet package has three main parts:
- The Screenplay Pattern’s core interfaces and classes
- Interactions for Selenium WebDriver
- Interactions for RestSharp
This structure is convenient for a test automation project that uses Selenium and RestSharp, but it forces projects that don’t use them to take on their dependencies. What if a project uses Playwright instead of Selenium, or RestAssured.NET instead of RestSharp? What if a project wants to make different kinds of interactions, like mobile interactions with Appium?
At its heart, the Screenplay Pattern is a generic pattern for any kind of interactions. In theory, the core pattern should not favor any particular tool or package. Anyone should be able to implement interaction libraries using the core pattern.
With that in mind, we intend to split the current Boa.Constrictor package into three separate packages, one for each of the existing parts. That way, a project can declare dependencies only on the parts of Boa Constrictor that it needs. It also enables us (and others) to develop new packages for different kinds of interactions.
One of the new interaction packages we intend to create is a library for Playwright interactions. Playwright is a fantastic new web testing framework from Microsoft. It provides several advantages over Selenium WebDriver, such as faster execution, automatic waiting, and trace logging.
We want to give people the ability to choose between Selenium WebDriver or Playwright for their web UI interactions. Since a test automation project would use only one, and since there could be overlap in the names and types of interactions, separating interaction packages as detailed in the previous section will be a prerequisite for developing Playwright support.
We may also try to develop an adapter for Playwright interactions that uses the same interfaces as Selenium interactions so that folks could switch from Selenium to Playwright without rewriting their interactions.
Another new interaction package we intend to create is a library for Applitools interactions. Applitools is the premier visual testing platform. Visual testing catches UI bugs that are difficult to catch with traditional assertions, such as missing elements, broken styling, and overlapping text. A Boa Constrictor package for Applitools interactions would make it easier to capture visual snapshots together with Selenium WebDriver interactions. It would also be an “optional” feature since it would be its own package.
Shadow DOM support
Shadow DOM is a technique for encapsulating parts of a web page. It enables a hidden DOM tree to be attached to an element in the “regular” DOM tree so that different parts between the two DOMs do not clash. Shadow DOM usage has become quite prevalent in web apps these days.
We intend to add support for Selenium interactions to pierce the shadow DOM. Selenium WebDriver requires extra calls to pierce the shadow DOM. Unfortunately, Boa Constrictor’s Selenium interactions currently do not support shadow DOM interactivity. Most likely, we will add new builder methods for Selenium-based Tasks and Questions that take in a locator for the shadow root element and then update the action methods to handle the shadow DOM if necessary.
.NET 7 targets
The main Boa Constrictor project, the unit tests project, and the example project all target .NET 5. Unfortunately, NET 5 is no longer supported by Microsoft. The latest release is .NET 7.
We intend to add .NET 7 targets. We will make the library packages target .NET 7, .NET 5 (for backwards compatibility), and .NET Standard 2.0 (again, for backwards compatibility). We will change the unit test and example projects to target .NET 7 exclusively. In fact, we have already made this change in version 2.0.2!
Many of Boa Constrictor’s dependencies have released new versions over the past year. GitHub’s Dependabot has also flagged some security vulnerabilities. It’s time to update dependency versions. This is standard periodic maintenance for any project. Already, we have updated our Selenium WebDriver dependencies to version 4.6.
Boa Constrictor has a doc site hosted using GitHub Pages. As we make the changes described above, we must also update the documentation for the project. Most notably, we will need to update our tutorial and example project, since the packages will be different, and we will have support for more kinds of interactions.
What’s the timeline?
The core contributors and I plan to implement these enhancements within the next three months:
- Today, we just released two new versions with incremental changes: 2.0.1 and 2.0.2.
- This week, we hope to split the existing package into three, which we intend to release as version 3.0.
- In December, we will refresh the GitHub Issues for the project.
- In January, the core contributors and I will host an in-person hackathon (a “Constrictathon”) in Cary, NC.
There is tons of work ahead, and we’d love for you to join us. Check out the GitHub repository, read our contributing guide, and join our Discord server!