Adding unit tests for TSTNode

.gitignore

@@ -1,25 +1,26 @@
-# FILES 
+# Files
+
 ands/algorithms/greedy/huffman.py
 ands/ds/Graph.py
-WARNINGS
+/ands/ds/MinPriorityQueue.py
 
 *.egg
 *.py[cod]
 *$py.class
 .DS_Store
 
-# DIRECTORIES
-ands/ds/TST/
-ands/algorithms/graphs
-ands/algorithms/unclassified
-ands/algorithms/numerical
 
-venv/
+# Directories
+
+ands/algorithms/graphs/
+ands/algorithms/unclassified/
+ands/algorithms/numerical/
+/ands/algorithms/math/combinatorics/
+/ands/algorithms/math/
+
+.idea/
 _ignore/
+venv/
 env/
 *.egg-info/
 __pycache__/
-.idea/
-/ands/algorithms/math/combinatorics/
-/ands/algorithms/math/
-/ands/ds/MinPriorityQueue.py

tests/ds/test_TSTNode.py

@@ -0,0 +1,113 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+
+
+"""
+# Meta info
+
+Author: Nelson Brochado
+Created: 29/01/2017
+Updated: 29/01/2017
+
+# Description
+
+Testing the TSTNode class inside TST.py.
+
+"""
+
+import unittest
+
+from ands.ds.TST import TSTNode
+
+
+class TestTSTNode(unittest.TestCase):
+    def test_create_key_not_string(self):
+        self.assertRaises(TypeError, TSTNode, 13)
+
+    def test_create_key_empty_string(self):
+        self.assertRaises(ValueError, TSTNode, "")
+
+    def test_create_acceptable_key(self):
+        self.assertIsInstance(TSTNode("unit testing"), TSTNode)
+
+    def test_create_default(self):
+        u = TSTNode("default values")
+        self.assertEqual(u.key, "default values")
+        self.assertIsNone(u.value)
+        self.assertIsNone(u.parent)
+        self.assertIsNone(u.mid)
+        self.assertIsNone(u.left)
+        self.assertIsNone(u.right)
+
+    def test_create_custom(self):
+        p = TSTNode("parent")
+        left = TSTNode("left")
+        mid = TSTNode("mid")
+        right = TSTNode("right")
+        u = TSTNode("u", 11, p, left, mid, right)
+        self.assertEqual(u.value, 11)
+        self.assertIs(u.parent, p)
+        self.assertIs(u.left, left)
+        self.assertIs(u.mid, mid)
+        self.assertIs(u.right, right)
+
+    def test_is_left_child_no_parent(self):
+        u = TSTNode("u")
+        self.assertRaises(AttributeError, u.is_left_child)
+
+    def test_is_left_child_false(self):
+        p = TSTNode("p")
+        u = TSTNode("u", 3, p)
+        self.assertFalse(u.is_left_child())
+
+    def test_is_left_child_true(self):
+        p = TSTNode("p")
+        u = TSTNode("u", 3, p)
+        p.left = u
+        self.assertTrue(u.is_left_child())
+
+    def test_is_right_child_no_parent(self):
+        u = TSTNode("u")
+        self.assertRaises(AttributeError, u.is_right_child)
+
+    def test_is_right_child_false(self):
+        p = TSTNode("p")
+        u = TSTNode("u", 3, p)
+        self.assertFalse(u.is_right_child())
+
+    def test_is_right_child_true(self):
+        p = TSTNode("p")
+        u = TSTNode("u", 3, p)
+        p.right = u
+        self.assertTrue(u.is_right_child())
+
+    def test_is_mid_child_no_parent(self):
+        u = TSTNode("u")
+        self.assertRaises(AttributeError, u.is_mid_child)
+
+    def test_is_mid_child_false(self):
+        p = TSTNode("p")
+        u = TSTNode("u", 3, p)
+        self.assertFalse(u.is_mid_child())
+
+    def test_is_mid_child_true(self):
+        p = TSTNode("p")
+        u = TSTNode("u", 3, p)
+        p.mid = u
+        self.assertTrue(u.is_mid_child())
+
+    def test_has_children_0(self):
+        u = TSTNode("u")
+        self.assertFalse(u.has_children())
+
+    def test_has_children_1(self):
+        u = TSTNode("u", right=TSTNode("right"))
+        self.assertTrue(u.has_children())
+
+    def test_has_children_2(self):
+        u = TSTNode("u", mid=TSTNode("mid"), left=TSTNode("left"))
+        self.assertTrue(u.has_children())
+
+    def test_has_children_3(self):
+        u = TSTNode("u", mid=TSTNode("mid"), left=TSTNode("left"), right=TSTNode("right"))
+        self.assertTrue(u.has_children())