Added find function

Author: dosart

binary_search_tree/binary_serch_tree.py

@@ -42,13 +42,28 @@ def add(self, key, value):
         else:
             self._add(key, value)
 
+    def find(self, key):
+        """Return value by key.
+
+        Args:
+            key: key for find value
+
+        Returns:
+            value: value if key exist else None
+        """
+        if self.is_empty():
+            return None
+        else:
+            return self._find(key)
+
     def _add(self, key, value):
         """Add the given key and object to tree(iterative version).
 
         Args:
             key:  key for value
             value: value by key
         """
+        parent = self._root
         cur = self._root
         while cur:
             parent = cur
@@ -64,3 +79,22 @@ def _add(self, key, value):
         else:
             parent.right = new_node
         self._count += 1
+
+    def _find(self, key):
+        """Return value by key.
+
+        Args:
+            key: key for find value
+
+        Returns:
+            value: value if key exist else None
+        """
+        cur = self._root
+        while cur:
+            if key > cur.key:
+                cur = cur.right
+            elif key < cur.key:
+                cur = cur.left
+            else:
+                return cur.value
+        return None

tests/test_binary_search_tree.py

@@ -31,9 +31,81 @@ def test_add_node1():
 def test_add_node2():
     bst = BinaryTree()
 
-    bst.add(29, 'Denis')
-    bst.add(35, 'Dima')
-    bst.add(28, 'Egor')
+    bst.add(29, "Denis")
+    bst.add(35, "Dima")
+    bst.add(28, "Egor")
 
     assert bst.is_empty() is False
     assert len(bst) == 3
+
+
+def test_add_node3():
+    bst = BinaryTree()
+
+    bst.add(29, "Denis")
+    bst.add(35, "Dima")
+    bst.add(28, "Egor")
+    bst.add(28, "E")
+
+    assert bst.is_empty() is False
+    assert len(bst) == 3
+
+
+def test_find_value1():
+    bst = BinaryTree()
+
+    result = bst.find("Key")
+    assert result is None
+
+
+def test_find_value2():
+    bst = BinaryTree()
+
+    bst.add(10, "Denis")
+
+    result = bst.find(10)
+    assert result == "Denis"
+
+
+def test_find_value3():
+    bst = BinaryTree()
+
+    bst.add(10, "Denis")
+    bst.add(11, "Dima")
+    bst.add(9, "Egor")
+
+    result = bst.find(11)
+    assert result == "Dima"
+
+
+def test_find_value4():
+    bst = BinaryTree()
+
+    bst.add(10, "Denis")
+    bst.add(11, "Dima")
+    bst.add(9, "Egor")
+
+    result = bst.find(9)
+    assert result == "Egor"
+
+
+def test_find_value5():
+    bst = BinaryTree()
+
+    bst.add(10, "Denis")
+    bst.add(11, "Dima")
+    bst.add(9, "Egor")
+
+    result = bst.find(11)
+    assert result == "Dima"
+
+
+def test_find_value6():
+    bst = BinaryTree()
+
+    bst.add(10, "Denis")
+    bst.add(11, "Dima")
+    bst.add(9, "Egor")
+
+    result = bst.find(13)
+    assert result is None