added test for gray

test/cmyk-test.coffee

@@ -3,12 +3,17 @@ vows = require 'vows'
 assert = require 'assert'
 chroma = require '../chroma'
 
+round = (digits) ->
+    d = Math.pow 10,digits
+    return (v) ->
+        Math.round(v*d) / d
+
 vows
     .describe('Testing CMYK color conversions')
     .addBatch
 
         'export simple colors to CMYK':
-            topic: ['black','white','red','#0f0','blue','yellow','cyan','magenta']
+            topic: ['black','white','red','#0f0','blue','yellow','cyan','magenta','gray']
             'black':   (t) -> assert.deepEqual chroma(t[0]).cmyk(), [0,0,0,1]
             'white':   (t) -> assert.deepEqual chroma(t[1]).cmyk(), [0,0,0,0]
             'red':     (t) -> assert.deepEqual chroma(t[2]).cmyk(), [0,1,1,0]
@@ -17,6 +22,7 @@ vows
             'yellow':  (t) -> assert.deepEqual chroma(t[5]).cmyk(), [0,0,1,0]
             'cyan':    (t) -> assert.deepEqual chroma(t[6]).cmyk(), [1,0,0,0]
             'magenta': (t) -> assert.deepEqual chroma(t[7]).cmyk(), [0,1,0,0]
+            'gray': (t) -> assert.deepEqual chroma(t[8]).cmyk().map(round(4)), [0,0,0,0.498]
 
         'parse simple CMYK colors':
             topic: [[0,0,0,1],[0,0,0,0],[0,1,1,0],[1,0,1,0],[1,1,0,0],[0,0,1,0],[1,0,0,0],[0,1,0,0]]