maybe wrong behaviour on params' request parameter

[marianoguerra]

here http://weavejester.github.io/ring-mock/ring.mock.request.html#var-request it says

Create a minimal valid request map from a HTTP method keyword, a string
containing a URI, and an optional map of parameters that will be added to
the query string of the URI. The URI can be relative or absolute. Relative
URIs are assumed to go to http://localhost.

but

user=> (:query-string (req/request :delete "/foo" {:id 4}))
nil

user=> (slurp (:body (req/request :delete "/foo" {:id 4})))
"id=4"

with this it works

user=> (:query-string (req/query-string (req/request :delete "/foo" {:id 4}) {:id 4}))
"id=4"

is the doc wrong, the code wrong or am I wrong? :)