Added find and some tests

Author: sbauer

linked_lists/linked_list.py

@@ -14,7 +14,7 @@ def insert(self, data):
     def append(self, data):
         new_node = Node(data)
 
-        if self.head is None:
+        if self.is_empty():
             self.head = new_node
             return
 
@@ -25,5 +25,20 @@ def append(self, data):
 
         current_node.next = new_node
 
+    def find(self, data):
+
+        if self.is_empty():
+            return None
+
+        current_node = self.head
+
+        while current_node is not None:
+            if current_node.data == data:
+                return current_node
+            
+            current_node = current_node.next
+            
+        return None
+
     def is_empty(self):
         return self.head == None

linked_lists/linked_list_tests.py

@@ -36,6 +36,22 @@ def test_appending_second_value_should_set_head_next(self):
         list.append("Second")
         self.assertEqual(list.head.next.data, "Second")
 
+    def test_find_on_empty_list_should_return_none(self):
+        list = LinkedList()
+        
+        self.assertIsNone(list.find("First"))
+
+    def test_find_should_match_valid_node_in_one_value_list(self):
+        list = LinkedList()
+        list.append("First")
+        self.assertIsNotNone(list.find("First"))
+
+    def test_find_should_match_valid_node_in_multi_value_list(self):
+        list = LinkedList()
+        list.append("First")
+        list.append("Second")
+        self.assertIsNotNone(list.find("Second"))
+
     def test_is_empty_should_be_true_if_no_head(self):
         list = LinkedList()
         self.assertTrue(list.is_empty())