
Visual UI Regression Testing with WebAssembly and the Kantu Selenium IDE - stevechu
https://a9t9.com/kantu/docs/visual-ui-testing
======
no_gravity
A nice way to do a quick visual regression test on the command line:

    
    
        cmp -s <( cutycapt devserver.com/somepage  ) \
               <( cutycapt liveserver.com/somepage )
    

At Product Chart, we use this in a small bash script that reads a config file
with a list of pages and tests them all for regressions:

[https://www.productchart.com/blog/2015-07-19-urldiff](https://www.productchart.com/blog/2015-07-19-urldiff)

~~~
Ulrich1
Nice link, this is an interesting blog post. But note that Kantu does much
more than just binary screenshot comparisons:

Kantu allows you to select specific areas of the website to test, and -
especially important - the image comparison is error-tolerant. That means that
(smaller) changes in image and font rendering do _not_ break the test. So a
test case created on the Mac works on Linux and Windows as well. In this
respect it is similar to Sikuli
([http://www.sikuli.org/](http://www.sikuli.org/) ) - but all inside a Chrome
and Firefox browser extension, with no external installations required.

Edit: More info about the choice of WASM for image search here:
[https://news.ycombinator.com/item?id=17574862](https://news.ycombinator.com/item?id=17574862)

