Try the JobStreet ELA at http://www.jobstreet.com/english.
You can choose to take practice tests or take the real assessment. Note that you can only do the assessment once every three months. You can take the practice tests as many times as you like. So, make sure you practice until you get it right before you take the assessment.
I took the practice test twice, getting 40/40 and 39/40 respectively, which means that (ahem) one of the questions is wrong :P.