[QA] Inconsistent Selenium behavior on different client OSes

[Jeff Hall]

The VisualEditor browser tests recently started failing because of an 
inability to locate page elements from the "toolGroup" menu, which 
includes formatting options for sub-headings, paragraph, page title, etc.

I updated the relevant page-object to a value that works fine when the 
test is executed on my MacBook targeting betalabs, and the same test 
runs fine when executed via Sauce Labs with Mac OS as the selected 
client platform.

The odd part is that if I run the same test targeting betalabs, but 
switch the client OS to either Ubuntu or Windows (WinXP, Win7, or Win8) 
using Sauce Labs, the test fails.  The problem is not with VisualEditor, 
which is working fine, but rather with something in the test framework.  
The page-object elements themselves are using CSS selectors, which I 
figured would be fairly bullet-proof.  They look like this:


   a(:subheading1, css: "a[class='oo-ui-tool-link'][title='^3']")
   a(:subheading2, css: "a[class='oo-ui-tool-link'][title='^4']")
   a(:subheading3, css: "a[class='oo-ui-tool-link'][title='^5']")
   a(:subheading4, css: "a[class='oo-ui-tool-link'][title='^6']")


Has anyone else run into a scenario like this, where an automated 
browser test only succeeds on select client platforms?  If so, did you 
discover any handy tips for altering the test to be more client-OS-agnostic?

Thanks,

Jeff