WebDriver Logic

The WebDriver Logic library provides a "mirror" of the clj-webdriver API using relations (see the core.logic library), including a powerful, declarative syntax for authoring your functional web tests and letting webdriver-logic make inferences about the state of your application.

Usage

Note: This library is in the earliest stages of development. Feedback is welcome; use at your own risk.

Check out the ClojureConj talk : Web Testing with Logic Programming

Exploration

Here's a simple example where we find the first element with a class of footer_nav:

(use 'webdriver-logic.core)
(require '[clj-webdriver.core :as wd])
(set-driver! {:browser :chrome} "https://github.com")

(run 1 [q]
  (attributeo q :class "footer_nav"))
;=> ({:webelement #<Tag: <ul>, Text: GitHub  About  Blog  Features  Contact & Support  Training  ..., Class: footer_nav, Object: [[ChromeDriver: chrome on MAC (26459fb4e495c6bf086ea92acbaa7715)] -> xpath: //*]>})

Or how about all the footer navigation sections?

(run* [q]
  (attributeo q :class "footer_nav"))
;=>
;; ({:webelement
;;   #<Tag: <ul>, Text: GitHub  About  Blog  Features  Contact & Support  Training  ..., Class: footer_nav, Object: [[ChromeDriver: chrome on MAC (6140efaa871769f2b7baa8fa885ebabc)] -> xpath: //*]>}
;;  {:webelement
;;   #<Tag: <ul>, Text: Clients  GitHub for Mac  GitHub for Windows  GitHub for Ecli..., Class: footer_nav, Object: [[ChromeDriver: chrome on MAC (6140efaa871769f2b7baa8fa885ebabc)] -> xpath: //*]>}
;;  {:webelement
;;   #<Tag: <ul>, Text: Tools  Gauges: Web analytics  Speaker Deck: Presentations  G..., Class: footer_nav, Object: [[ChromeDriver: chrome on MAC (6140efaa871769f2b7baa8fa885ebabc)] -> xpath: //*]>}
;;  {:webelement
;;   #<Tag: <ul>, Text: Documentation  GitHub Help  Developer API  GitHub Flavored M..., Class: footer_nav, Object: [[ChromeDriver: chrome on MAC (6140efaa871769f2b7baa8fa885ebabc)] -> xpath: //*]>})

How about the first three elements on the page that have a legitimate id attribute?

(run 3 [q]
  (fresh [an-element a-value]
    (attributeo an-element :id a-value)
    (!= a-value nil)
    (!= a-value "")
    (== q [a-value an-element])))
;=>
;; (["gauges-tracker"
;;   {:webelement
;;    #<Tag: <script>, Id: gauges-tracker, Source: https://secure.gaug.es/track.js, Object: [[ChromeDriver: chrome on MAC (1fc632cc0ded7fc2c7fa1db418329876)] -> xpath: //*]>}]
;;  ["wrapper"
;;   {:webelement
;;    #<Tag: <div>, Text: Signup and Pricing  Explore GitHub  Features  Blog  Sign in ..., Id: wrapper, Object: [[ChromeDriver: chrome on MAC (1fc632cc0ded7fc2c7fa1db418329876)] -> xpath: //*]>}]
;;  ["header"
;;   {:webelement
;;    #<Tag: <div>, Text: Signup and Pricing  Explore GitHub  Features  Blog  Sign in, Id: header, Class: true clearfix, Object: [[ChromeDriver: chrome on MAC (1fc632cc0ded7fc2c7fa1db418329876)] -> xpath: //*]>}])

And if we limit the search domain to a sub-set of elements on the page (in this case, only div elements):

(binding [*search-domain* {:xpath "//div"}]
  (run 3 [q]
       (fresh [an-element a-value]
              (attributeo an-element :id a-value)
              (!= a-value nil)
              (!= a-value "")
              (== q [a-value an-element]))))
;=>
;; (["wrapper"
;;   {:webelement
;;    #<Tag: <div>, Text: Signup and Pricing  Explore GitHub  Features  Blog  Sign in ..., Id: wrapper, Object: [[ChromeDriver: chrome on MAC (1fc632cc0ded7fc2c7fa1db418329876)] -> xpath: //div]>}]
;;  ["header"
;;   {:webelement
;;    #<Tag: <div>, Text: Signup and Pricing  Explore GitHub  Features  Blog  Sign in, Id: header, Class: true clearfix, Object: [[ChromeDriver: chrome on MAC (1fc632cc0ded7fc2c7fa1db418329876)] -> xpath: //div]>}]
;;  ["footer-push"
;;   {:webelement
;;    #<Tag: <div>, Id: footer-push, Object: [[ChromeDriver: chrome on MAC (1fc632cc0ded7fc2c7fa1db418329876)] -> xpath: //div]>}])

Pretty simple - you could do that with regular CSS or XPath queries. One could argue, however, that even at this simple point the declarative nature of run* is easier to follow and reason about than a series of explicit find-element, filter or remove calls.

Let's make the inference work harder for us. Are there two links included in both the header and footer that have the same href value?

(binding [*search-domain* {:xpath "//a"}
          *child-search-domain* {:xpath ".//a"}]
  (run 2 [q]
     (fresh [header-el footer-el the-href-value]
            (attributeo header-el :href the-href-value)
            (attributeo footer-el :href the-href-value)
            (!= the-href-value nil)
            (!= the-href-value "")
            (childo header-el (wd/find-element driver {:id "header"}))
            (childo footer-el (wd/find-element driver {:id "footer"}))
            (== q [the-href-value header-el footer-el]))))
;=>
;; (["https://github.com/features"
;;   {:webelement
;;    #<Tag: <a>, Text: Features, Href: https://github.com/features, Object: [[ChromeDriver: chrome on MAC (1fc632cc0ded7fc2c7fa1db418329876)] -> xpath: //a]>}
;;   {:webelement
;;    #<Tag: <a>, Text: Features, Href: https://github.com/features, Object: [[ChromeDriver: chrome on MAC (1fc632cc0ded7fc2c7fa1db418329876)] -> xpath: //a]>}]
;;  ["https://github.com/blog"
;;   {:webelement
;;    #<Tag: <a>, Text: Blog, Href: https://github.com/blog, Object: [[ChromeDriver: chrome on MAC (1fc632cc0ded7fc2c7fa1db418329876)] -> xpath: //a]>}
;;   {:webelement
;;    #<Tag: <a>, Text: Blog, Href: https://github.com/blog, Object: [[ChromeDriver: chrome on MAC (1fc632cc0ded7fc2c7fa1db418329876)] -> xpath: //a]>}])

You'll notice again the binding of *search-domain* and *child-search-domain* to a subset of all anchor elements on the page. Though this is not necessary for the program to run, it drastically improves performance. Relations like attributeo have to traverse all the elements on the page to find an answer, which for Selenium-WebDriver means creating lots of objects.

You can flash these elements to convince yourself that the above works:

(require '[clj-webdriver.element :as el])

(doseq [[_ h f] (binding [*search-domain* {:xpath "//a"}
                          *child-search-domain* {:xpath ".//a"}]
                  (run 2 [q]
                    (fresh [header-el footer-el the-href-value]
                      (attributeo header-el :href the-href-value)
                      (attributeo footer-el :href the-href-value)
                      (!= the-href-value nil)
                      (!= the-href-value "")
                      (childo header-el (wd/find-element driver {:id "header"}))
                      (childo footer-el (wd/find-element driver {:id "footer"}))
                      (== q [the-href-value header-el footer-el]))))]
  (wd/flash h)
  (wd/flash f))

Larger and more meaningful examples forthcoming.

Writing Your Tests

Given that core.logic returns values that can be consumed by "regular" functions, it's not hard to imagine how to compose tests against those values. But in the spirit of Prolog unit tests, webdriver-logic provides a handful of macros that wrap clojure.test's is macro for common Logic Programming cases:

• s - Succeeds if a single value is returned from the relation (deterministic behavior)
• s+ - Succeeds if more than one value is returned from the relation (non-deterministic behavior)
• s-as - Succeeds if its first parameter = the value returned from the relation
• s-includes - Succeeds if its first parameter contains values that are included in the value returned from the relation
• s? - Succeeds if its first parameter, a predicate, returns true when passed the seq of values returned from the relation
• u - Succeeds if the relation fails

Remember that core.logic run* and friends always return a seq of zero or more values.

For examples of these in action, please see this library's test suite.

Contributing

This library is currently in the earliest stages of development. Pull requests against master are welcome, preferably authored in a feature branch.

Run the tests with Leiningen:

lein test

Note: If you just want to run the example app that webdriver-logic uses for its testing purposes, do the following:

• Open a terminal and run lein repl or at the root of this project
• Evaluate (use 'webdriver-logic.test.example-app.core 'ring.adapter.jetty)
• Evaluate (defonce my-server (run-jetty #'routes {:port 5744, :join? false})) (make sure your port selection doesn't conflict with actual test runs)

Logic Programming Materials

Clojure/Lisp

• The Reasoned Schemer (also available in Kindle format)
• README for core.logic
• Ambrose Bonnaire-Sergeant's Logic Starter tutorial

Prolog

• Learn Prolog Now
• Artifical Intelligence through Prolog
• The Art of Prolog, 2nd Edition
• Prolog Programming for Artificial Intelligence

License

Copyright (C) 2011 Daniel L. Gregoire (semperos)

Distributed under the Eclipse Public License, the same as Clojure.