refactor exercise word-search

* rewrite tests so that users have more freedom of implementation
* update example-implementation to fit test-interface
* reduce skeleton to minimal as discussed in exercism#272

exercises/word-search/example.py

@@ -1,57 +1,22 @@
-import copy
-
-
-class Point(object):
-    def __init__(self, x, y):
-        self.x = x
-        self.y = y
-
-    def __repr__(self):
-        return 'Point({}:{})'.format(self.x, self.y)
-
-    def __add__(self, other):
-        return Point(self.x + other.x, self.y + other.y)
-
-    def __sub__(self, other):
-        return Point(self.x - other.x, self.y - other.y)
-
-    def __eq__(self, other):
-        return self.x == other.x and self.y == other.y
-
-    def __ne__(self, other):
-        return not(self == other)
-
-
-DIRECTIONS = (Point(1, 0), Point(1, -1), Point(1, 1), Point(-1, -1),
-              Point(0, -1), Point(0, 1), Point(-1, 1), Point(-1, 0))
-
-
-class WordSearch(object):
-    def __init__(self, puzzle):
-        self.rows = puzzle.split()
-        self.width = len(self.rows[0])
-        self.height = len(self.rows)
-
-    def find_char(self, coordinate):
-        if coordinate.x < 0 or coordinate.x >= self.width:
-            return
-        if coordinate.y < 0 or coordinate.y >= self.height:
-            return
-        return self.rows[coordinate.y][coordinate.x]
-
-    def find(self, word, position, direction):
-            current = copy.copy(position)
-            for letter in word:
-                if self.find_char(current) != letter:
-                    return
-                current += direction
-            return position, current - direction
-
-    def search(self, word):
-        positions = (Point(x, y) for x in range(self.width) for y in range(self.height))
-        for pos in positions:
-            for d in DIRECTIONS:
-                result = self.find(word, pos, d)
-                if result:
-                    return result
-        return None
+def find_stop(row, column, word, puzzle):
+    directions = [(0, 1), (0, -1), (1, 0), (1, 1), (1, -1), (-1, 0), (-1, 1), (-1, -1)]
+    for d in directions:
+        row_nr, column_nr = row, column
+        for char_nr, char in enumerate(word):
+            try:
+                if puzzle[row_nr][column_nr] != char:
+                    break
+            except IndexError:
+                break
+            if char_nr == len(word) - 1:
+                return row_nr, column_nr
+            row_nr += d[0]
+            column_nr += d[1]
+
+
+def search(puzzle, word):
+    for row_nr, row in enumerate(puzzle):
+        for column_nr, char in enumerate(row):
+            stop = find_stop(row_nr, column_nr, word, puzzle)
+            if stop:
+                return (row_nr, column_nr), stop

exercises/word-search/word_search.py

@@ -1,27 +1,2 @@
-class Point(object):
-    def __init__(self, x, y):
-        self.x = x
-        self.y = y
-
-    def __repr__(self):
-        return 'Point({}:{})'.format(self.x, self.y)
-
-    def __add__(self, other):
-        return Point(self.x + other.x, self.y + other.y)
-
-    def __sub__(self, other):
-        return Point(self.x - other.x, self.y - other.y)
-
-    def __eq__(self, other):
-        return self.x == other.x and self.y == other.y
-
-    def __ne__(self, other):
-        return not(self == other)
-
-
-class WordSearch(object):
-    def __init__(self, puzzle):
-        pass
-
-    def search(self, word):
-        return None
+def search():
+    pass

exercises/word-search/word_search_test.py

@@ -1,83 +1,53 @@
 import unittest
 
-from word_search import WordSearch, Point
+from word_search import search
 
 
 class WordSearchTests(unittest.TestCase):
 
-    @classmethod
-    def setUpClass(self):
-        puzzle = ('jefblpepre\n'
-                  'camdcimgtc\n'
-                  'oivokprjsm\n'
-                  'pbwasqroua\n'
-                  'rixilelhrs\n'
-                  'wolcqlirpc\n'
-                  'screeaumgr\n'
-                  'alxhpburyi\n'
-                  'jalaycalmp\n'
-                  'clojurermt')
-        self.example = WordSearch(puzzle)
+    puzzle = ['jefblpepre',
+              'camdcimgtc',
+              'oivokprjsm',
+              'pbwasqroua',
+              'rixilelhrs',
+              'wolcqlirpc',
+              'screeaumgr',
+              'alxhpburyi',
+              'jalaycalmp',
+              'clojurermt']
 
     def test_horizontal_words_left_to_right(self):
-        self.assertEqual(
-            self.example.search('clojure'),
-            (Point(0, 9), Point(6, 9))
-        )
+        self.assertEqual(search(WordSearchTests.puzzle, 'clojure'), ((9, 0), (9, 6)))
 
     def test_horizontal_words_right_to_left(self):
-        self.assertEqual(
-            self.example.search('elixir'),
-            (Point(5, 4), Point(0, 4))
-        )
+        self.assertEqual(search(WordSearchTests.puzzle, 'elixir'), ((4, 5), (4, 0)))
 
     def test_vertical_words_top_to_bottom(self):
-        self.assertEqual(
-            self.example.search('ecmascript'),
-            (Point(9, 0), Point(9, 9))
-        )
+        self.assertEqual(search(WordSearchTests.puzzle, 'ecmascript'), ((0, 9), (9, 9)))
 
     def test_vertical_words_bottom_to_top(self):
-        self.assertEqual(
-            self.example.search('rust'),
-            (Point(8, 4), Point(8, 1))
-        )
-
-    def test_diagonal_words_top_left_to_bottom_right(self):
-        self.assertEqual(
-            self.example.search('java'),
-            (Point(0, 0), Point(3, 3))
-        )
-
-    def test_diagonal_upper_bottom_right_to_top_left(self):
-        self.assertEqual(
-            self.example.search('lua'),
-            (Point(7, 8), Point(5, 6))
-        )
-
-    def test_diagonal_upper_bottom_left_to_top_right(self):
-        self.assertEqual(
-            self.example.search('lisp'),
-            (Point(2, 5), Point(5, 2))
-        )
-
-    def test_diagonal_upper_top_right_to_bottom_left(self):
-        self.assertEqual(
-            self.example.search('ruby'),
-            (Point(7, 5), Point(4, 8))
-        )
+        self.assertEqual(search(WordSearchTests.puzzle, 'rust'), ((4, 8), (1, 8)))
+
+    def test_diagonal_top_left_to_bottom_right(self):
+        self.assertEqual(search(WordSearchTests.puzzle, 'java'), ((0, 0), (3, 3)))
+
+    def test_diagonal_bottom_right_to_top_left(self):
+        self.assertEqual(search(WordSearchTests.puzzle, 'lua'), ((8, 7), (6, 5)))
+
+    def test_diagonal_bottom_left_to_top_right(self):
+        self.assertEqual(search(WordSearchTests.puzzle, 'lisp'), ((5, 2), (2, 5)))
+
+    def test_diagonal_top_right_to_bottom_left(self):
+        self.assertEqual(search(WordSearchTests.puzzle, 'ruby'), ((5, 7), (8, 4)))
 
     def test_words_that_are_not_in_the_puzzle(self):
-        self.assertIsNone(self.example.search('haskell'))
+        self.assertIsNone(search(WordSearchTests.puzzle, 'haskell'))
 
     def test_search_differently_sized_puzzles(self):
-        puzzle = ('qwertyuiopz\n'
-                  'luamsicrexe\n'
-                  'abcdefghijk')
-        self.assertEqual(
-            WordSearch(puzzle).search('exercism'),
-            (Point(10, 1), Point(3, 1))
-        )
+        puzzle = ['qwertyuiopz',
+                  'luamsicrexe',
+                  'abcdefghijk']
+        self.assertEqual(search(puzzle, 'exercism'), ((1, 10), (1, 3)))
 
 
 if __name__ == '__main__':