binary-search: clean up

exercises/binary-search/binary_search_test.py

@@ -1,27 +1,41 @@
 import unittest
 
-from example import binary_search
+from binary_search import binary_search
 
 
 class BinarySearchTests(unittest.TestCase):
 
-    def test_raises_error_if_list_is_not_sorted(self):
-        self.assertRaises(ValueError, binary_search, [44, 5, 2, 1, 4], 6)
+    def test_finds_value_in_array_with_one_element(self):
+        self.assertEqual(0, binary_search([6], 6))
 
-    def test_raises_error_if_list_is_empty(self):
-        self.assertRaises(ValueError, binary_search, [], 1)
+    def test_finds_value_in_middle_of_array(self):
+        self.assertEqual(3, binary_search([1, 3, 4, 6, 8, 9, 11], 6))
+
+    def test_finds_value_at_beginning_of_array(self):
+        self.assertEqual(0, binary_search([1, 3, 4, 6, 8, 9, 11], 1))
+
+    def test_finds_value_at_end_of_array(self):
+        self.assertEqual(6, binary_search([1, 3, 4, 6, 8, 9, 11], 11))
 
-    def test_list_item_not_found(self):
-        self.assertEqual("Item not found.",
-                         binary_search([1, 2, 3, 4, 5, 6], 23))
+    def test_finds_value_in_array_of_odd_length(self):
+        self.assertEqual(9, binary_search(
+            [1, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 634], 144))
 
-    def test_list_item_found(self):
-        self.assertEqual(3, binary_search([1, 2, 3, 4, 5, 6, 7, 8], 4))
+    def test_finds_value_in_array_of_even_length(self):
+        self.assertEqual(5, binary_search(
+            [1, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377], 21))
 
-    def test_list_item_found_larger_list(self):
-        self.assertEqual(7, binary_search(
-            [1, 5, 6, 7, 8, 9, 12, 14, 16, 22, 47, 100, 123], 14))
+    def test_identifies_value_missing(self):
+        self.assertRaises(ValueError, binary_search, [1, 3, 4, 6, 8, 9, 11], 7)
 
+    def test_value_smaller_than_arrays_minimum(self):
+        self.assertRaises(ValueError, binary_search, [1, 3, 4, 6, 8, 9, 11], 0)
+
+    def test_value_larger_than_arrays_maximum(self):
+        self.assertRaises(ValueError, binary_search, [1, 3, 4, 6, 8, 9, 11], 13)
+
+    def test_empty_array(self):
+        self.assertRaises(ValueError, binary_search, [], 1)
 
 if __name__ == '__main__':
     unittest.main()

exercises/binary-search/example.py

@@ -1,6 +1,4 @@
 def binary_search(search_list, value):
-    list_empty(search_list)
-    list_sorted(search_list)
     low = 0
     high = len(search_list) - 1
     while low <= high:
@@ -11,14 +9,4 @@ def binary_search(search_list, value):
             low = middle + 1
         else:
             return middle
-    return "Item not found."
-
-
-def list_sorted(search_list):
-    if not sorted(search_list) == search_list:
-        raise ValueError("This list must be sorted.")
-
-
-def list_empty(search_list):
-    if not search_list:
-        raise ValueError('This list has no items.')
+    raise ValueError("Value not found.")