We have a mobile version of website for our company and even Google mobile site test passes our main website as mobile friendly but Google guidelines says to use responsive layout which we are not using. So does that mean Google may penalize our website for not being mobile compatible? Right now we just redirect mobile users to our mini website which is built to fit on small screens. Is this acceptable?
Google supports a separate mobile site. From their mobile webmaster guidelines:
There are 3 ways to go mobile: responsive web design, dynamic serving, and separate URLs.
Separate URLs: Serves different code to each device, and on separate URLs. This configuration tries to detect the users’ device, then redirects to the appropriate page using HTTP redirects] along with the Vary HTTP header.
It goes on to say that when you use a separate mobile site, you have to be very careful about the redirects. Each page on the desktop site has to redirect to the corresponding page on the mobile site. You can't just redirect every page on the desktop site to the home page of the mobile site.
I suspect that this is your problem. If your site is redirecting to mobile correctly, you shouldn't get the warnings in Google Webmaster Tools.
If your site passing Mobile friendly test, Then you should don't worry about it. The mobile friendly test just checkout The user interface and how your web coding are displayed in mobile. Many of HTML and CSS codes working fine with mobile version and hence your site are passed through mobile friendly test.
If you are working on mobile site, then you should check the user agent first, If Users coming from mobile, then you should redirect to mobile version of site like m.example.com. In reality, If you want to know, How your site treat with Google? then open Google Webmaster Fetch tools, then simply enter your site name, There are 4 option available, one for desktop and other three for mobile. select second one, and enter your site, if your site redirect to mobile version then your site is working fine with mobile version site, otherwise you should fix that.
Note: Always mention URL, to get correct answer.
Google does not penalize anyone for not being mobile-friendly. You may gain a few "points" if you are but they do not penalize you.
Responsive layout is a technique to adapt pages to devices and not a search engine optimization. However, it is one of the ways to accomplish the goal of a mobile friendly site.
Since you redirect people to your mobile friendly page, you accomplish the same goal.
Also don't forget about Google Official Speed Check Tool. Here you can check all optimization recomendations for desktop and mobile devices. Usually there's enough to have 80 points of 100 for mobile device.
Of course everyone knows that on 21st of April there is a new update coming up but I believe that none of the non-mobile friendly sites will be penalised. There is too much non-mobile friendly sites with a very important content which they can't penalise. The only thing is that your site might be getting less SEO score and be listed in rankings below your competitors which are mobile-friendly. Check the link below and test your site. If it pass this test you will be all right during 21st ;-)