Issues with Word Automation Services in SharePoint 2010

This week we had an issue with Word Automation Services, in one of our test servers, where our custom code (really boiler plate code, see below) would fail on the second line:

var context = SPServiceContext.GetContext(SPsite);
var wsaProxy = (WordServiceApplicationProxy)context.GetDefaultProxy(typeof(WordServiceApplicationProxy));

Since the same code was working fine in our development environment, it was clear that it was not the code that was at fault but our SharePoint configuration that was at fault.

The issue was that the Word Automation Services Application had not been configured to be added to the default proxy list, see screenshot below, and thus the code was failing to get the proxy.

Note that this adding Word Automation services is done from the Central Administration website:
Central Administration -> Manage Service Applications -> New Word Automation Service