a7fe11fd74
- Implemented Randomized Quicksort algorithm with performance analysis - Implemented Hash Table with Chaining for collision resolution - Added comprehensive test suite (30+ test cases) - Created test runner script with multiple test options - Added detailed README with architecture diagrams and documentation - Added MIT License - Includes examples and comprehensive documentation
219 lines
6.3 KiB
Python
219 lines
6.3 KiB
Python
"""
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Unit tests for Hash Table with Chaining implementation.
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"""
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import unittest
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from src.hash_table import HashTable, HashNode
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class TestHashTable(unittest.TestCase):
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"""Test cases for hash table with chaining."""
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def test_initialization(self):
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"""Test hash table initialization."""
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ht = HashTable(initial_size=16)
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self.assertEqual(ht.size, 16)
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self.assertEqual(len(ht), 0)
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self.assertEqual(ht.get_load_factor(), 0.0)
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def test_insert_and_get(self):
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"""Test basic insert and get operations."""
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ht = HashTable()
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ht.insert(1, "apple")
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ht.insert(2, "banana")
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self.assertEqual(ht.get(1), "apple")
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self.assertEqual(ht.get(2), "banana")
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self.assertEqual(len(ht), 2)
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def test_insert_update(self):
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"""Test that inserting same key updates value."""
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ht = HashTable()
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ht.insert(1, "apple")
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ht.insert(1, "banana")
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self.assertEqual(ht.get(1), "banana")
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self.assertEqual(len(ht), 1)
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def test_get_nonexistent_key(self):
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"""Test getting a key that doesn't exist."""
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ht = HashTable()
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ht.insert(1, "apple")
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self.assertIsNone(ht.get(2))
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def test_delete_existing_key(self):
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"""Test deleting an existing key."""
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ht = HashTable()
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ht.insert(1, "apple")
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ht.insert(2, "banana")
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deleted = ht.delete(1)
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self.assertTrue(deleted)
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self.assertIsNone(ht.get(1))
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self.assertEqual(ht.get(2), "banana")
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self.assertEqual(len(ht), 1)
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def test_delete_nonexistent_key(self):
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"""Test deleting a key that doesn't exist."""
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ht = HashTable()
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ht.insert(1, "apple")
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deleted = ht.delete(2)
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self.assertFalse(deleted)
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self.assertEqual(len(ht), 1)
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def test_contains(self):
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"""Test contains method."""
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ht = HashTable()
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ht.insert(1, "apple")
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self.assertTrue(ht.contains(1))
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self.assertFalse(ht.contains(2))
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def test_in_operator(self):
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"""Test using 'in' operator."""
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ht = HashTable()
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ht.insert(1, "apple")
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self.assertIn(1, ht)
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self.assertNotIn(2, ht)
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def test_load_factor(self):
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"""Test load factor calculation."""
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ht = HashTable(initial_size=4)
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# Initially empty
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self.assertEqual(ht.get_load_factor(), 0.0)
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# Add elements
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ht.insert(1, "a")
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self.assertEqual(ht.get_load_factor(), 0.25)
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ht.insert(2, "b")
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self.assertEqual(ht.get_load_factor(), 0.5)
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ht.insert(3, "c")
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self.assertEqual(ht.get_load_factor(), 0.75)
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def test_resize(self):
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"""Test automatic resizing when load factor threshold is reached."""
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ht = HashTable(initial_size=4, load_factor_threshold=0.75)
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# Insert elements to trigger resize
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ht.insert(1, "a")
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ht.insert(2, "b")
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ht.insert(3, "c")
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# This should trigger resize (3/4 = 0.75)
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ht.insert(4, "d")
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# Size should have doubled
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self.assertEqual(ht.size, 8)
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# All elements should still be accessible
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self.assertEqual(ht.get(1), "a")
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self.assertEqual(ht.get(2), "b")
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self.assertEqual(ht.get(3), "c")
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self.assertEqual(ht.get(4), "d")
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self.assertEqual(len(ht), 4)
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def test_get_all_items(self):
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"""Test getting all items from hash table."""
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ht = HashTable()
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ht.insert(1, "apple")
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ht.insert(2, "banana")
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ht.insert(3, "cherry")
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items = ht.get_all_items()
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self.assertEqual(len(items), 3)
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# Check that all items are present
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item_dict = dict(items)
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self.assertEqual(item_dict[1], "apple")
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self.assertEqual(item_dict[2], "banana")
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self.assertEqual(item_dict[3], "cherry")
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def test_collision_handling(self):
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"""Test that collisions are handled correctly."""
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ht = HashTable(initial_size=5)
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# Insert keys that might collide
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keys = [1, 6, 11, 16, 21]
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for key in keys:
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ht.insert(key, f"value_{key}")
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# All keys should be retrievable
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for key in keys:
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self.assertEqual(ht.get(key), f"value_{key}")
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self.assertEqual(len(ht), len(keys))
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def test_delete_from_chain(self):
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"""Test deleting an element from the middle of a chain."""
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ht = HashTable(initial_size=5)
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# Create a chain by inserting colliding keys
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keys = [1, 6, 11]
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for key in keys:
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ht.insert(key, f"value_{key}")
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# Delete middle element
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deleted = ht.delete(6)
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self.assertTrue(deleted)
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# Remaining elements should still be accessible
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self.assertEqual(ht.get(1), "value_1")
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self.assertIsNone(ht.get(6))
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self.assertEqual(ht.get(11), "value_11")
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self.assertEqual(len(ht), 2)
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def test_len(self):
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"""Test __len__ method."""
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ht = HashTable()
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self.assertEqual(len(ht), 0)
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ht.insert(1, "a")
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self.assertEqual(len(ht), 1)
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ht.insert(2, "b")
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self.assertEqual(len(ht), 2)
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ht.delete(1)
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self.assertEqual(len(ht), 1)
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def test_multiple_operations(self):
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"""Test a sequence of mixed operations."""
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ht = HashTable()
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# Insert
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ht.insert(1, "one")
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ht.insert(2, "two")
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ht.insert(3, "three")
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# Update
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ht.insert(2, "TWO")
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# Delete
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ht.delete(1)
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# Verify final state
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self.assertIsNone(ht.get(1))
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self.assertEqual(ht.get(2), "TWO")
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self.assertEqual(ht.get(3), "three")
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self.assertEqual(len(ht), 2)
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def test_empty_hash_table(self):
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"""Test operations on empty hash table."""
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ht = HashTable()
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self.assertIsNone(ht.get(1))
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self.assertFalse(ht.contains(1))
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self.assertFalse(ht.delete(1))
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self.assertEqual(ht.get_all_items(), [])
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self.assertEqual(len(ht), 0)
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if __name__ == '__main__':
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unittest.main()
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