[Issue #82] with-num-trials provides a nice syntax for multiple for…

…mulas to generate n trials each

src/midje/ideas/formulas.clj

@@ -80,6 +80,10 @@
        (finally
          ~conclusion-signal))))
 
+(defmacro with-num-trials [num-trials & formulas]
+  `(binding [midje.ideas.formulas/*num-trials* ~num-trials]
+     ~@formulas))
+
 (def future-formula-variant-names (map #(str % "formula") future-prefixes))
 
 (defn- check-part-of [form]

test/midje/ideas/t_formulas.clj

@@ -4,7 +4,7 @@
   (:use midje.test-util
         midje.sweet
         midje.util.ecosystem
-        [midje.ideas.formulas :only [*num-trials*]] ))
+        [midje.ideas.formulas :only [*num-trials* with-num-trials]] ))
 
 
 ;;;; Formulas
@@ -52,6 +52,14 @@
 (fact @my-str-count => 77)
 
 
+;; There is syntactic sugar for binding *num-trials*
+(defn-call-countable k-maker [] "k")
+(with-num-trials 1000 
+  (formula [a 1] (k-maker) => "k")
+  (formula [a 1] (k-maker) => "k")
+  (formula [a 1] (k-maker) => "k"))
+(fact @k-maker-count => 3000)
+
 ;; Can specify number of trials to run in options map - overrides *num-trials* var value
 (defn-call-countable foo-maker [] "foo")
 (defn-call-countable my-double-str [s] (str "double" s))