stoichiograph

commit b6a00eb46d798a18ead99c4c8e47ccb6d8609bf4
parent 065583bed4d5b26ecd8ac594bb9d034fcab2959e
Author: Amin Mesbah <mesbah.amin@gmail.com>
Date:   Tue, 10 Jan 2017 16:24:05 -0800

Raise informative exception for unmappable words.

Diffstat:
M
elemental_speller.py
 | 
7
++++++-
M
tests.py
 | 
5
+++++

2 files changed, 11 insertions(+), 1 deletion(-)
diff --git a/elemental_speller.py b/elemental_speller.py
@@ -79,7 +79,6 @@ def generate_groupings(word_length, group_sizes=(1, 2)):
     return groupings
 
 
-# TODO(amin): Handle failure cases (grouping doesn't add up to word length)
 def map_word(word, grouping):
     """Return a word mapped to a grouping.
 
@@ -87,6 +86,12 @@ def map_word(word, grouping):
     >>> map_word('because', (1, 2, 1, 1, 2))
     ('b', 'ec', 'a', 'u', 'se')
     """
+    if len(word) != sum(grouping):
+        raise ValueError(
+            'Word length ({}) != sum of elements in grouping ({})'.format(
+                len(word), sum(grouping))
+        )
+
     chars = (c for c in word)
 
     mapped = []
diff --git a/tests.py b/tests.py
@@ -1,3 +1,4 @@
+import pytest
 import elemental_speller as es
 
 ELEMENTS = (
@@ -34,6 +35,10 @@ def test_map_word():
     assert es.map_word('because', (1, 2, 1, 1, 2)) == ('b', 'ec', 'a', 'u', 'se')
     assert es.map_word('osiris', (1, 3, 2)) == ('o', 'sir', 'is')
 
+    with pytest.raises(ValueError):
+        es.map_word('toolong', (2, 1))
+        es.map_word('short', (2, 2, 2))
+
 
 def test_elemental_spelling():
     assert es.spell('amputation') == [