in functional test, assert_redirected_to w prefix

I had to use sub-URI deployment (could not use subdomains..), and when running my functional tests, I the redirected_to assertion embed the prefix.. quite normal ;-))

is there a way to stipulate this prefix in the test setup to avoid hard-coding in all the tests ?

Expected response to be a redirect to <http://test.host/my/page&gt; but was a redirect to <http://test.host/intranet/my/page&gt;

/intranet being the prefix in this case ..

many thanks for your suggestions

erwin