Skip to content

Instantly share code, notes, and snippets.

@acthp
Created October 16, 2017 00:06
Show Gist options
  • Save acthp/d7ec06acfb341e295705bc2433057852 to your computer and use it in GitHub Desktop.
Save acthp/d7ec06acfb341e295705bc2433057852 to your computer and use it in GitHub Desktop.
test.check shrinking of 2d matrix
(ns matrix-test.core-test
(:require [clojure.test :refer :all]
[clojure.test.check :as tc]
[clojure.test.check.generators :as gen]
[clojure.test.check.properties :as prop]
[matrix-test.core :refer :all]))
(def element gen/int)
(defn matrix-size [[w h]]
(apply gen/tuple (repeat h (apply gen/tuple (repeat w element)))))
; generate a matrix by binding the size
(def matrix
(gen/bind (gen/tuple gen/s-pos-int gen/s-pos-int) matrix-size))
;
;
(defn new-row [m]
(apply gen/tuple (repeat (count (first m)) element)))
(defn new-col [m]
(apply gen/tuple (repeat (count m) element)))
(defn add-row [m]
(gen/fmap #(conj m %) (new-row m)))
(defn add-col [m]
(gen/fmap #(mapv conj m %) (new-col m)))
(defn matrix-inc [m]
(gen/bind (gen/frequency [[10 (gen/return :ret)] [45 (gen/return :row)] [45 (gen/return :col)]])
(fn [op]
(case op
:ret (gen/return m)
:row (gen/bind (add-row m) matrix-inc)
:col (gen/bind (add-col m) matrix-inc)))))
; generate a matrix by incrementally adding rows and columns
(def matrix2
(gen/bind (gen/fmap #(-> [[%]]) element) matrix-inc))
;
;
; coerce failure on an unusual condition
(defn matrix-ok [m]
(< (count (filter #(= % 4) (map last m))) 3))
;(gen/sample (matrix-size [2 3]))
;(gen/sample matrix)
;(gen/sample matrix2)
;(tc/quick-check 1000 (prop/for-all [m matrix] (matrix-ok m)))
;(tc/quick-check 1000 (prop/for-all [m matrix2] (matrix-ok m)))
@gfredericks
Copy link

(tc/quick-check 1000 (prop/for-all [m matrix] (not-any? #{97} (apply concat m)))) shrinks to

[[0 0 0 0 0 0 0]                                                                                                                                  
 [0 0 0 0 0 0 0]                                                                                                                                  
 [0 0 0 0 0 0 0]                                                                                                                                  
 [0 0 0 0 0 0 0]                                                                                                                                  
 [0 0 0 0 0 0 0]                                                                                                                                  
 [0 0 0 0 0 0 0]                                                                                                                                  
 [0 0 0 0 0 0 0]                                                                                                                                  
 [0 0 0 0 0 0 0]                                                                                                                                  
 [0 0 0 0 0 0 0]                                                                                                                                  
 [0 0 0 0 0 0 0]                                                                                                                                  
 [0 0 0 0 0 0 0]                                                                                                                                  
 [0 0 0 0 0 0 0]                                                                                                                                  
 [0 0 0 0 0 0 0]                                                                                                                                  
 [0 0 0 0 0 0 0]                                                                                                                                  
 [0 0 0 0 0 0 0]                                                                                                                                  
 [0 0 0 0 0 0 0]                                                                                                                                  
 [0 0 0 0 0 0 0]                                                                                                                                  
 [0 0 0 0 0 0 0]                                                                                                                                  
 [0 0 0 0 0 0 0]                                                                                                                                  
 [0 0 0 0 0 0 0]                                                                                                                                  
 [0 0 0 0 0 97 0]                                                                                                                                 
 [0 0 0 0 0 0 0]]     

and (tc/quick-check 1000 (prop/for-all [m matrix2] (not-any? #{97} (apply concat m)))) shrinks to

[[0 0]                                                                                                                                            
 [0 0]                                                                                                                                            
 [0 0]                                                                                                                                            
 [0 0]                                                                                                                                            
 [0 0]                                                                                                                                            
 [0 0]                                                                                                                                            
 [0 0]                                                                                                                                            
 [0 0]                                                                                                                                            
 [0 0]                                                                                                                                            
 [0 0]                                                                                                                                            
 [0 0]                                                                                                                                            
 [0 0]                                                                                                                                            
 [0 0]                                                                                                                                            
 [0 0]                                                                                                                                            
 [0 0]                                                                                                                                            
 [0 0]                                                                                                                                            
 [0 0]                                                                                                                                            
 [0 0]                                                                                                                                            
 [97 0]                                                                                                                                           
 [0 0]                                                                                                                                            
 [0 0]                                                                                                                                            
 [0 0]                                                                                                                                            
 [0 0]                                                                                                                                            
 [0 0]]

whereas ideally it would shrink to [[97]].

@acthp
Copy link
Author

acthp commented Oct 16, 2017

yeah, it's not ideal, just better, at least for the conditions I've tested.

@gfredericks
Copy link

oh okay. I don't know what your goal was then.

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment