Verifying CSS updates with Capybara detection

Question

Verifying CSS updates with Capybara detection

I'm in the process of developing a web application that dynamically changes its CSS styles based on user input. Everything is working smoothly, but I'm facing an issue with my automated tests not confirming whether the CSS updates are actually taking place.

Essentially, I just need to validate if the content within a <style> tag in the document's <head> has been modified to a specific value. For my testing, I am utilizing capybara (with the selenium driver) and have written the following code:

styles = page.all('style')
styles.length.should == 1
styles[0].text.should == style

Everything seems to be functioning correctly until the last line, where it fails because styles[0].text always returns an empty string. I've attempted using .value, which consistently returns nil. Despite this, I am fairly certain that the CSS changes are being applied, as I can visually see them in the Firefox window that the tests are executing in.

So, my question is - is there a method to access the contents of the <style> tag using capybara?

css ruby selenium capybara

Answer 1

Answer №1

It appears that Capybara, particularly with Selenium, may not display certain style content due to it being wrapped in an HTML comment and therefore ignored. For example:

<STYLE type="text/css">
    <!--
    .newfont { color:red; font-style:italic }
    -->
</STYLE>

However, you can access the page's source using page.source to retrieve the style content. Since the source is essentially a large string, one way to extract this information is by parsing it using Nokogiri (which is already included with Capybara):

page = Nokogiri::HTML.parse(page.source)
page.css('style').first.text

# => "\n&lt;!--\n.newfont { color:red; font-style:italic }\n--&gt;\n"

If you need to verify customizable styles and are utilizing Selenium, another approach could involve using Javascript to determine the calculated style of an element. There are plenty of resources available on how to do this using Javascript. You could utilize Capybara's page.evaluate_script method to execute Javascript code that reveals how a specific element is visually rendered, which might be more reliable than comparing CSS text, especially if it undergoes minification within the application.

Answer 2

It appears that Capybara, particularly with Selenium, may not display certain style content due to it being wrapped in an HTML comment and therefore ignored. For example:

<STYLE type="text/css">
    <!--
    .newfont { color:red; font-style:italic }
    -->
</STYLE>

However, you can access the page's source using page.source to retrieve the style content. Since the source is essentially a large string, one way to extract this information is by parsing it using Nokogiri (which is already included with Capybara):

page = Nokogiri::HTML.parse(page.source)
page.css('style').first.text

# => "\n&lt;!--\n.newfont { color:red; font-style:italic }\n--&gt;\n"

If you need to verify customizable styles and are utilizing Selenium, another approach could involve using Javascript to determine the calculated style of an element. There are plenty of resources available on how to do this using Javascript. You could utilize Capybara's page.evaluate_script method to execute Javascript code that reveals how a specific element is visually rendered, which might be more reliable than comparing CSS text, especially if it undergoes minification within the application.

Answer 3

Answer №2

Ensure that the page contains ".selector" with the text "Some Text"
Make sure that the element with ".selector" has a value of "Some Value"
Check if there is only one element with the class ".selector"

Alternatively,

Retrieve the value of the element with the class "selector"
Retrieve the value of the first child element with the class "selector"

There are multiple methods to achieve what you want. It would be beneficial to refer to the Capybara documentation for more information.

Additionally, please keep in mind that if you are attempting to access these changes post a javascript event, it is necessary to execute this using Selenium (or an equivalent tool). Alternatively, Jasmine.js can also be utilized for this purpose.

Answer 4

Ensure that the page contains ".selector" with the text "Some Text"
Make sure that the element with ".selector" has a value of "Some Value"
Check if there is only one element with the class ".selector"

Alternatively,

Retrieve the value of the element with the class "selector"
Retrieve the value of the first child element with the class "selector"

There are multiple methods to achieve what you want. It would be beneficial to refer to the Capybara documentation for more information.

Additionally, please keep in mind that if you are attempting to access these changes post a javascript event, it is necessary to execute this using Selenium (or an equivalent tool). Alternatively, Jasmine.js can also be utilized for this purpose.

Verifying CSS updates with Capybara detection

Answer №1

Answer №2

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