When you setup a test to multiple attempts, you might receive feedback from students that they cannot take another attempt because there is no option to do that. It is a flaw in the design for the Test tool and the solution to the problem can be better explained by watching this short video:
http://screencast.com/t/6rqF5lHDG
screenshot of the link to click to take the second attempt:
http://screencast.com/t/9cOrxa03
http://screencast.com/t/6rqF5lHDG
screenshot of the link to click to take the second attempt:
http://screencast.com/t/9cOrxa03