How to include tests when creating a Dockerfile

I created a dockerfile a couple of months ago that creates a linux image with a couple of anaconda python virtual environments with different packages.

Due to some reason, one of the modules in python35 cannot be imported anymore (GDAL) which raised a bigger question: How to include tests when writing dockerfiles?

I want to test if the modules work as expected for the different python environments. Some modules do not throw errors during installation but have some broken dependencies, hence the testing.

A first import test would already be helpful:

in python27

import module1 
import module2
..
import moduleN

in python35

import module1  
import module2 
..
import moduleN

The workflow would be as follows: Compile image -> Run tests -> Dissemination using docker hub

How to include the testing step in this workflow?