Google is always testing, here is another one spotted this time by Andrea Cruz. In this one, Google is testing showing the URL, in black, but under the clickable title of the snippet. The current design should show the URL above the clickable title but in this test, it is below.

Here is the screen shot of the test shared by Andrea on Twitter (click to enlarge):

Here is what you would normally see today (click to enlarge):

Forum discussion at Twitter.