midje provides does not work in let bindings

gistfile1.clj

(use 'midje.sweet)

(defn mocked [x] "ERROR: THIS SHOULDN'T HAVE BEEN CALLED")

(defn handler [r]
  (let [body (mocked (get-in r [:params :id]))]
    {:status (if (re-find #"ERROR" body) 500 200) 
     :body body
     :content-type "text/plain"
     }
))


;;. FAIL at (NO_SOURCE_FILE:1)
;;.     Expected: 200
;;.       Actual: 500
;;. 
;;. FAIL at (NO_SOURCE_FILE:1)
;;. You claimed the following was needed, but it was never used:
;;.     (mocked 3)
;;. 
;;. FAIL at (NO_SOURCE_FILE:1)
;;.     Expected: "OK"
;;.       Actual: "ERROR: THIS SHOULDN'T HAVE BEEN CALLED"
(fact "Fails: mocks do not work in let bindings"
  (let [request {:params {:id 3}}
        response (handler 1)]
    (:status response) => 200
    (:body response) => "OK")
  (provided
    (mocked 3) => "OK" :times 1
    ))

(comment
(do
 (midje.util.report/fact-begins)
 (midje.internal-ideas.wrapping/midje-wrapped
  (midje.internal-ideas.fakes/with-installed-fakes
   (midje.ideas.background/background-fakes)
   (do
    fact
    "Fails: mocks do not work in let bindings"
    (let
     [request {:params {:id 3}} response (handler 1)]
     (midje.internal-ideas.wrapping/midje-wrapped
      (midje.semi-sweet/expect
       (:status response)
       =>
       200
       :position
       (midje.internal-ideas.file-position/line-number-known 1)))
     (midje.internal-ideas.wrapping/midje-wrapped
      (midje.semi-sweet/expect
       (:body response)
       =>
       "OK"
       :position
       (midje.internal-ideas.file-position/line-number-known 1)
       (midje.semi-sweet/fake
        (mocked 3)
        =>
        "OK"
        :position
        (midje.internal-ideas.file-position/line-number-known 1)
        :times
        1)))))))
 (midje.util.report/fact-checks-out?))
)

;;. The journey is the reward. -- traditional
(fact "This works, but IMHO is more difficult to read when validating multiple properties"
  (let [request {:params {:id 3}}]   
    (handler request)) => (contains {:status 200 :body "OK" :content-type "text/plain"})
  (provided
    (mocked 3) => "OK" :times 1
    ))

;;. Work joyfully and peacefully, knowing that right thoughts and right
;;. efforts will inevitably bring about right results. -- Allen
(fact "Can also use predicates, but not as obvious as => syntax"
  (let [request {:params {:id 3}}]   
    (handler request)  => (contains {:status pos? :body (complement nil?)}))
  (provided
    (mocked 3) => "OK" :times 1
    ))