addition of support for a distance of 1 (#17)

spellchecker/spellchecker.py

@@ -20,9 +20,12 @@ class SpellChecker(object):
             for no dictionary. Supported languages are `en`, `es`, `de`, and \
             `fr`. Defaults to `en`
             local_dictionary (str): The path to a locally stored word \
-            frequency dictionary '''
+            frequency dictionary
+            distance (int): The edit distance to use. Defaults to 2'''
 
-    def __init__(self, language='en', local_dictionary=None):
+
+    def __init__(self, language='en', local_dictionary=None, distance=2):
+        self._distance = distance
         self._word_frequency = WordFrequency()
         if local_dictionary:
             self._word_frequency.load_dictionary(local_dictionary)
@@ -95,8 +98,9 @@ def candidates(self, word):
                 word (str): The word for which to calculate candidate spellings
             Returns:
                 set: The set of words that are possible candidates '''
+
         return (self.known([word]) or self.known(self.edit_distance_1(word)) or
-                self.known(self.edit_distance_2(word)) or {word})
+                (self._distance == 2 and self.known(self.edit_distance_2(word))) or {word})
 
     def known(self, words):
         ''' The subset of `words` that appear in the dictionary of words

tests/resources/small_dictionary.json

@@ -1,5 +1,6 @@
 {
     "a": 1,
     "b": 2,
-    "apple": 45
+    "apple": 45,
+    "bike": 60
 }

tests/spellchecker_test.py

@@ -6,7 +6,6 @@
 
 from spellchecker import SpellChecker
 
-
 class TestSpellChecker(unittest.TestCase):
     ''' test the spell checker class '''
 
@@ -117,6 +116,13 @@ def test_load_external_dictionary(self):
         self.assertEqual(spell['a'], 1)
         self.assertTrue('apple' in spell)
 
+    def test_edit_distance_one(self):
+        ''' test a case where edit distance must be one '''
+        here = os.path.dirname(__file__)
+        filepath = '{}/resources/small_dictionary.json'.format(here)
+        spell = SpellChecker(language=None, local_dictionary=filepath, distance=1)
+        self.assertEqual(spell.candidates('hike'), {'bike'})
+
     def test_edit_distance_two(self):
         ''' test a case where edit distance must be two '''
         here = os.path.dirname(__file__)