diff --git a/exercises/luhn/luhn.spec.coffee b/exercises/luhn/luhn.spec.coffee
index 0870388..9c78d32 100644
--- a/exercises/luhn/luhn.spec.coffee
+++ b/exercises/luhn/luhn.spec.coffee
@@ -2,46 +2,70 @@ Luhn = require './luhn'
 
 describe 'Luhn', ->
 
-  it "check digit", ->
-    luhn = new Luhn(34567)
-    expect(luhn.checkDigit).toEqual(7)
+  it 'single digit strings can not be valid', ->
+    luhn = new Luhn('1')
+    expect(luhn.valid).toEqual(false)
 
-  xit "check digit again", ->
-    luhn = new Luhn(91370)
-    expect(luhn.checkDigit).toEqual(0)
+  xit 'a single zero is invalid', ->
+    luhn = new Luhn('0')
+    expect(luhn.valid).toEqual(false)
 
-  xit "addends", ->
-    luhn = new Luhn(12121)
-    expect(luhn.addends).toEqual([1, 4, 1, 4, 1])
+  xit 'a simple valid SIN that remains valid if reversed', ->
+    luhn = new Luhn('059')
+    expect(luhn.valid).toEqual(true)
 
-  xit "too large added", ->
-    luhn = new Luhn(8631)
-    expect(luhn.addends).toEqual([7, 6, 6, 1])
+  xit 'a simple valid SIN that becomes invalid if reversed', ->
+    luhn = new Luhn('59')
+    expect(luhn.valid).toEqual(true)
 
-  xit "checksum", ->
-    luhn = new Luhn(4913)
-    expect(luhn.checksum).toEqual(22)
+  xit 'a valid Canadian SIN', ->
+    luhn = new Luhn('055 444 286')
+    expect(luhn.valid).toEqual(true)
 
-  xit "checksum again", ->
-    luhn = new Luhn(201773)
-    expect(luhn.checksum).toEqual(21)
+  xit 'invalid credit card', ->
+    luhn = new Luhn('8273 1232 7352 0569')
+    expect(luhn.valid).toEqual(false)
 
-  xit "invalid number", ->
-    luhn = new Luhn(738)
+  xit 'invalid credit card', ->
+    luhn = new Luhn('8273 1232 7352 0569')
     expect(luhn.valid).toEqual(false)
 
-  xit "valid number", ->
-    luhn = new Luhn(8739567)
+  xit 'valid number with an even number of digits', ->
+    luhn = new Luhn('095 245 88')
     expect(luhn.valid).toEqual(true)
 
-  xit "create valid number", ->
-    number = Luhn.create(123)
-    expect(number).toEqual(1230)
+  xit 'valid number with an odd number of spaces', ->
+    luhn = new Luhn('234 567 891 234')
+    expect(luhn.valid).toEqual(true)
 
-  xit "create other valid number", ->
-    number = Luhn.create(873956)
-    expect(number).toEqual(8739567)
+  xit 'valid strings with a non-digit added at the end become invalid', ->
+    luhn = new Luhn('059a')
+    expect(luhn.valid).toEqual(false)
 
-  xit "create yet another valid number", ->
-    number = Luhn.create(837263756)
-    expect(number).toEqual(8372637564)
+  xit 'valid strings with punctuation included become invalid', ->
+    luhn = new Luhn('055-444-285')
+    expect(luhn.valid).toEqual(false)
+
+  xit 'valid strings with symbols included become invalid', ->
+    luhn = new Luhn('055# 444$ 285')
+    expect(luhn.valid).toEqual(false)
+
+  xit 'single zero with space is invalid', ->
+    luhn = new Luhn(' 0')
+    expect(luhn.valid).toEqual(false)
+
+  xit 'more than a single zero is valid', ->
+    luhn = new Luhn('0000 0')
+    expect(luhn.valid).toEqual(true)
+
+  xit 'input digit 9 is correctly converted to output digit 9', ->
+    luhn = new Luhn('091')
+    expect(luhn.valid).toEqual(true)
+
+  xit 'using ascii value for non-doubled non-digit isn\'t allowed', ->
+    luhn = new Luhn('055b 444 285')
+    expect(luhn.valid).toEqual(false)
+
+  xit 'using ascii value for non-doubled non-digit isn\'t allowed', ->
+    luhn = new Luhn(':9')
+    expect(luhn.valid).toEqual(false)