If you see an error that looks like this:
It is because the root directory ( in the example above /Projects ) is not listed in Docker's File Sharing tab. To add your root directory, simply open up Dockers Preferences, select File Sharing and add the root folder to the list. Then you can rerun your Docker command without issue.
If you see this error, Docker is not running.
To run Code Coverage Reports you will need to have Xdebug installed. You can check if you have Xdebug installed via php -i | grep xdebug
If you are developing on OSX and you do not have Xdebug installed, you can install it via Homebrew brew install php70-xdebug.