re-write unit test to get around strange test failure on circleci.

test/metabase/models/session_test.clj

@@ -2,23 +2,28 @@
   (:require [expectations :refer :all]
             [korma.core :as k]
             [metabase.models.session :refer :all]
+            [metabase.models.user :refer [User]]
+            [metabase.test.util :refer :all]
             [metabase.test.data.users :refer :all]))
 
 ;; first-session-for-user
 (expect
   "the-greatest-day-ever"
-  (do
+  (with-temp User [{:keys [id]} {:first_name (random-name)
+                                 :last_name  (random-name)
+                                 :email      (str (random-name) "@metabase.com")
+                                 :password   "nada"}]
     (k/insert Session
               (k/values [{:id         "the-greatest-day-ever"
-                          :user_id    (user->id :rasta)
+                          :user_id    id
                           :created_at (metabase.util/->Timestamp "1980-10-19")}
                          {:id         "the-world-of-bi-changes-forever"
-                          :user_id    (user->id :rasta)
+                          :user_id    id
                           :created_at (metabase.util/->Timestamp "2015-10-21")}
                          {:id         "something-could-have-happened"
-                          :user_id    (user->id :rasta)
+                          :user_id    id
                           :created_at (metabase.util/->Timestamp "1999-12-31")}
                          {:id         "now"
-                          :user_id    (user->id :rasta)
+                          :user_id    id
                           :created_at (metabase.util/new-sql-timestamp)}]))
-    (first-session-for-user (user->id :rasta))))
+    (first-session-for-user id)))