Using 'get' in rspec controller test, doesn't work with array value for parameter

This may be the wrong forum for this, but I think I'll ask here anyway
because the method in question is one of Rails integration testing
methods and not actually implemented by rspec.

I'm trying to spec the retrieve action of my AssetsController, which
takes a wildcard route of the form "/assets/*path". I'm trying to test
it like so:

  it "should render the correct text asset with the correct MIME type
and encoding" do
    get "retrieve", { :path => ['stylesheets', 'bar.css'] }

This fails with the error "undefined method `each' for
"stylesheets":String". I have a feeling that this is a dumb mistake
somehow and I'm just not using the method correctly. Any insight on my
possible stupidity would be greatly appreciated.