Watir grew out of Ruby code written by Chris Morris in 2001 to control Internet Explorer through its COM interface.(1) In 2003 Paul Rogers and Bret Pettichord began using this code to test websites and open sourced the project under the name WTR.(2) An Agile XP conference in August of 2004 prompted the team to rename the project to Watir and redesign the code base using TDD principles, re-using existing code where possible.(3) The first commit with the new name is from September 30, 2004.(4)
Original versions of Selenium were focused on being a test framework with its own HTML table based Domain Specific Language (DSL). It had some technological limitations and issues with flexibility, as well as offering multiple ways of doing similar things. Its big advantage was its support for all of the various browsers that were starting to steal market share from Microsoft. To keep up with Selenium, various groups created browser specific projects for Watir including FireWatir, OperaWatir, SafariWatir, and ChromeWatir).
As the WebDriver drivers matured, Selenium found the WebDriver solutions appealing enough to agree to merge the projects. While Selenium 2.0 effectively emulated Selenium 1.0 (RC) for backward compatibility, adopting WebDriver’s object oriented driver approach required significant code updates. Since Watir had always used the “driver” approach, Watir users ironically had much fewer adjustments to make in their code than Selenium users did in order to be able to leverage the full power of WebDriver.
When Jari Bakken, a Watir developer, was exposed to WebDriver in 2009, he began developing a Ruby implementation of it for both Selenium and Watir. Jari had already written Celerity, a JRuby project to implement a wrapper for HtmlUnit, to provide a headless testing option with the same API as Watir. With his work on watir-webdriver, he decided to take the Celerity specs and make them usable for both projects.(7). In doing so he created the WatirSpec repository which could be used by any of the Ruby-based projects that implemented the Watir API.
The functionality being provided by WebDriver caused the Watir team to add features and change its conventions when it made sense to do so. The big backward-incompatible change in the Watir 2.0 (released in August of 2011) was the move from one-indexing to zero-indexing. Indexing “like a person” makes sense until you have to constantly figure out if you are working with a Watir Collection or a Ruby Array (or with WebDriver). The challenge of bringing Watir into complete compliance with the WatirSpec was taken up by Jarmo Pertman and culminated in the release of Watir 3.0 in April 2012.
To encourage the use of watir-webdriver, Hugh McGowan renamed the Watir code base “watir-classic” and created a “meta” repository that would default to using the watir-classic implementation for Internet Explorer and using the watir-webdriver implementation for all other browsers. This code was implemented by Jarmo and released as Watir 4.0 in Sepetember 2012.
In January of 2015 Jari decided to step down as maintainer of the selenium-webdriver and watir-webdriver gems.(8). Alex Rodionov had been an active contributor for the previous three years and took over primary ownership of the project with assistance from Titus Fortner who was working with Bret at Blackbaud at that time and had just been officially added to the development team.
With Microsoft releasing the Edge browser and announcing that no new features would be added to Internet Explorer, the need for the watir-classic code to be actively maintained dramatically diminished. Also at this time there was significant confusion around what Watir was and what gems should be used; it was not uncommon for Watir users to say they were running with “Watir WebDriver, not Watir.” Since the tester-focused API has always been the key distinguishing feature for Watir, not the implementation, the project needed to refocus and disambiguate. In 2016 Titus spearheaded this move, deprecating both watir-classic and watir-webdriver gems and releasing Watir 6.0 with a new logo, a new website and an updated version of the Selenium-backed code. Based on numerous conversations with Bret about the original ideology behind Watir, Titus updated Watir to become less like an alternative implementation of Selenium, and to more fully leverage the Watir API to remove extra configurations and add default waiting behaviors that better adhered to the original spirit of Watir.
All of this is to say that instead of being a competitor to Selenium, the current version of Watir relies on the Selenium code for the browser automation capabilities of WebDriver. Think of Selenium as a Browser Automation Library and Watir as a Test Automation Library. Selenium provides the means for a user to interact with a browser with a “do what I say” approach, whereas Watir leverages Selenium to allow a user to accomplish a “do what I mean” approach to testing the UI.