Testing with docker containers instead of virtual machines

I have a question regarding using docker for testing.

Our main solution is a client/server solution. However, the same server is also being used by our web applications. We know that our web applications, server and SQL Database can run in docker container, as it is today.

All our customers are currently running our web applications and server on either physical servers, or virtual machines.

From my knowledge that is obtained from the docker website, docker courses and the following stackoverflow post, there is a difference between a Virtual Machine and a Docker container.

But could there be such a big difference that our automated testing would have a different output or unable to catch errors in a docker container compared to a virtual machine?

From my understanding the main difference is that containers runs on host os, and VM's runs on its own instance of a OS. So, from my view the difference is not big enough to change the output of our testing in anyway?

Setup

Our container setup would be the exact same as it is in our VM testing environment

• MS-SQL Server container
• Server container (Windows container)
• IIS Container