Incorrect response header with functional test?

I’m testing a controller by doing an ajax post to create an entry,
then a normal get to see that entry show up on a page. After the get
the @response.body is correct, but @response.headers still says the
content type is “text/javascript”, so assert_select doesn’t work. It
seems like the second request, the get, would set the content type to
“text/html” since it’s just a normal page. Am I off base here? Any
help is appreciated.