Function test_specific_problematic_case

python/tests/test_proper_deletion.py:52–78

Test the specific case that was creating single-child parents

()

def test_specific_problematic_case():
    """Test the specific case that was creating single-child parents"""
    tree = BPlusTreeMap(capacity=4)  # Minimum viable capacity

    # Build a larger case to stress test the deletion logic
    for i in range(16):
        tree[i] = f"value_{i}"

    print("Built tree with items 0-15")
    assert check_invariants(tree), "Initial tree should be valid"

    # Delete in a problematic order that stresses merge/redistribute logic
    problematic_deletes = [1, 3, 5, 7, 9, 11, 13, 15, 0, 2, 4, 6, 8, 10, 12, 14]

    for key in problematic_deletes:
        print(f"\nDeleting {key}...")
        del tree[key]

        invariants_ok = check_invariants(tree)
        print(f"Invariants OK: {invariants_ok}")

        if not invariants_ok:
            print("Structure after violation:")
            _print_structure(tree.root, 0)
            assert False, f"Invariants violated after deleting {key}"

    print("✅ Problematic case now maintains invariants!")


def test_merge_vs_redistribute():