diff --git a/Gruntfile.coffee b/Gruntfile.coffee
index a57a1d5ea..f11582ef9 100755
--- a/Gruntfile.coffee
+++ b/Gruntfile.coffee
@@ -25,6 +25,10 @@ module.exports = (grunt) ->
     output = if parts2.length is 0 then '""' else parts2.join ' + '
     "(innerHTML: #{output})"
 
+  assert = (statement, objs...) ->
+    return '' unless grunt.config('pkg').tests_enabled
+    "throw new Error 'Assertion failed: ' + `#{JSON.stringify statement}` unless #{statement}"
+
   # Project configuration.
   grunt.initConfig
     pkg: grunt.file.readJSON 'package.json'
@@ -35,6 +39,7 @@ module.exports = (grunt) ->
           pkg = grunt.config 'pkg'
           pkg.importHTML = importHTML
           pkg.html = html
+          pkg.assert = assert
           pkg.tests_enabled or= false
           pkg
         enumerable: true
diff --git a/src/Linkification/Linkify.coffee b/src/Linkification/Linkify.coffee
index ebd12b44c..2e06952fe 100755
--- a/src/Linkification/Linkify.coffee
+++ b/src/Linkification/Linkify.coffee
@@ -52,16 +52,20 @@ Linkify =
 
             endNode  = saved
             {data}   = saved
-            word    += data
-            {length} = data
 
             if end = space.exec data
               # Set our snapshot and regex to start on this node at this position when the loop resumes
+              word += data[...end.index]
               test.lastIndex = length = end.index
               i--
               break
+            else
+              {length} = data
+              word    += data
 
-        links.push Linkify.makeRange node, endNode, index, length if Linkify.regString.exec word
+        if Linkify.regString.exec word
+          links.push Linkify.makeRange node, endNode, index, length
+          <%= assert('word is links[links.length-1].toString()') %>
 
         break unless test.lastIndex and node is endNode
 
@@ -105,7 +109,7 @@ Linkify =
     # Clean start of range
     i = text.search Linkify.regString
 
-    if i
+    if i > 0
       text = text.slice i
       i-- while range.startOffset + i >= range.startContainer.data.length