test-avl-tree.c

/*

Copyright (c) 2005-2008, Simon Howard

Permission to use, copy, modify, and/or distribute this software
for any purpose with or without fee is hereby granted, provided
that the above copyright notice and this permission notice appear
in all copies.

THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL
WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE
AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR
CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

 */

#include <assert.h>
#include <stdio.h>
#include <stdlib.h>

#include "alloc-testing.h"
#include "framework.h"

#include "avl-tree.h"
#include "compare-int.h"

#define NUM_TEST_VALUES 1000

int test_array[NUM_TEST_VALUES];

#if 0
/* Tree print function - useful for debugging. */
static void print_tree(AVLTreeNode *node, int depth)
{
	int *value;
	int i;

	if (node == NULL) {
		return;
	}

	print_tree(avl_tree_node_child(node, AVL_TREE_NODE_LEFT), depth + 1);

	for (i=0; i<depth*6; ++i) {
		printf(" ");
	}

	value = avl_tree_node_key(node);
	printf("%i\n", *value);

	print_tree(avl_tree_node_child(node, AVL_TREE_NODE_RIGHT), depth + 1);
}
#endif

int find_subtree_height(AVLTreeNode *node)
{
	AVLTreeNode *left_subtree;
	AVLTreeNode *right_subtree;
	int left_height, right_height;

	if (node == NULL) {
		return 0;
	}

	left_subtree = avl_tree_node_child(node, AVL_TREE_NODE_LEFT);
	right_subtree = avl_tree_node_child(node, AVL_TREE_NODE_RIGHT);
	left_height = find_subtree_height(left_subtree);
	right_height = find_subtree_height(right_subtree);

	if (left_height > right_height) {
		return left_height + 1;
	} else {
		return right_height + 1;
	}
}

/* Validates a subtree, returning its height */
int counter;

int validate_subtree(AVLTreeNode *node)
{
	AVLTreeNode *left_node, *right_node;
	int left_height, right_height;
	int *key;

	if (node == NULL) {
		return 0;
	}

	left_node = avl_tree_node_child(node, AVL_TREE_NODE_LEFT);
	right_node = avl_tree_node_child(node, AVL_TREE_NODE_RIGHT);

	/* Check the parent references of the children */
	if (left_node != NULL) {
		assert(avl_tree_node_parent(left_node) == node);
	}
	if (right_node != NULL) {
		assert(avl_tree_node_parent(right_node) == node);
	}

	/* Recursively validate the left and right subtrees,
	 * obtaining the height at the same time. */
	left_height = validate_subtree(left_node);

	/* Check that the keys are in the correct order */
	key = (int *) avl_tree_node_key(node);

	assert(*key > counter);
	counter = *key;

	right_height = validate_subtree(right_node);

	/* Check that the returned height value matches the
	 * result of avl_tree_subtree_height(). */
	assert(avl_tree_subtree_height(left_node) == left_height);
	assert(avl_tree_subtree_height(right_node) == right_height);

	/* Check this node is balanced */
	assert(left_height - right_height < 2 &&
	       right_height - left_height < 2);

	/* Calculate the height of this node */
	if (left_height > right_height) {
		return left_height + 1;
	} else {
		return right_height + 1;
	}
}

void validate_tree(AVLTree *tree)
{
	AVLTreeNode *root_node;
	int height;

	root_node = avl_tree_root_node(tree);

	if (root_node != NULL) {
		height = find_subtree_height(root_node);
		assert(avl_tree_subtree_height(root_node) == height);
	}

	counter = -1;
	validate_subtree(root_node);
}

AVLTree *create_tree(void)
{
	AVLTree *tree;
	int i;

	/* Create a tree and fill with nodes */
	tree = avl_tree_new((AVLTreeCompareFunc) int_compare);

	for (i = 0; i < NUM_TEST_VALUES; ++i) {
		test_array[i] = i;
		avl_tree_insert(tree, &test_array[i], &test_array[i]);
	}

	return tree;
}

void test_avl_tree_new(void)
{
	AVLTree *tree;

	tree = avl_tree_new((AVLTreeCompareFunc) int_compare);

	assert(tree != NULL);
	assert(avl_tree_root_node(tree) == NULL);
	assert(avl_tree_num_entries(tree) == 0);

	avl_tree_free(tree);

	/* Test out of memory scenario */
	alloc_test_set_limit(0);

	tree = avl_tree_new((AVLTreeCompareFunc) int_compare);

	assert(tree == NULL);
}

void test_avl_tree_insert_lookup(void)
{
	AVLTree *tree;
	AVLTreeNode *node;
	unsigned int i;
	int *value;

	/* Create a tree containing some values. Validate the
	 * tree is consistent at all stages. */
	tree = avl_tree_new((AVLTreeCompareFunc) int_compare);

	for (i = 0; i < NUM_TEST_VALUES; ++i) {
		test_array[i] = (int) i;
		avl_tree_insert(tree, &test_array[i], &test_array[i]);

		assert(avl_tree_num_entries(tree) == i + 1);
		validate_tree(tree);
	}

	assert(avl_tree_root_node(tree) != NULL);

	/* Check that all values can be read back again */
	for (i = 0; i < NUM_TEST_VALUES; ++i) {
		node = avl_tree_lookup_node(tree, &i);
		assert(node != NULL);
		value = avl_tree_node_key(node);
		assert(*value == (int) i);
		value = avl_tree_node_value(node);
		assert(*value == (int) i);
	}

	/* Check that invalid nodes are not found */
	i = NUM_TEST_VALUES + 100;
	assert(avl_tree_lookup_node(tree, &i) == NULL);

	avl_tree_free(tree);
}

void test_avl_tree_child(void)
{
	AVLTree *tree;
	AVLTreeNode *root;
	AVLTreeNode *left;
	AVLTreeNode *right;
	int values[] = {1, 2, 3};
	int *p;
	int i;

	/* Create a tree containing some values. Validate the
	 * tree is consistent at all stages. */
	tree = avl_tree_new((AVLTreeCompareFunc) int_compare);

	for (i = 0; i < 3; ++i) {
		avl_tree_insert(tree, &values[i], &values[i]);
	}

	/* Check the tree */
	root = avl_tree_root_node(tree);
	p = avl_tree_node_value(root);
	assert(*p == 2);

	left = avl_tree_node_child(root, AVL_TREE_NODE_LEFT);
	p = avl_tree_node_value(left);
	assert(*p == 1);

	right = avl_tree_node_child(root, AVL_TREE_NODE_RIGHT);
	p = avl_tree_node_value(right);
	assert(*p == 3);

	/* Check invalid values */
	assert(avl_tree_node_child(root, 10000) == NULL);
	assert(avl_tree_node_child(root, 2) == NULL);

	avl_tree_free(tree);
}

void test_out_of_memory(void)
{
	AVLTree *tree;
	AVLTreeNode *node;
	int i;

	/* Create a tree */
	tree = create_tree();

	/* Set a limit to stop any more entries from being added. */
	alloc_test_set_limit(0);

	/* Try to add some more nodes and verify that this fails. */
	for (i = 10000; i < 20000; ++i) {
		node = avl_tree_insert(tree, &i, &i);
		assert(node == NULL);
		validate_tree(tree);
	}

	avl_tree_free(tree);
}

void test_avl_tree_free(void)
{
	AVLTree *tree;

	/* Try freeing an empty tree */
	tree = avl_tree_new((AVLTreeCompareFunc) int_compare);
	avl_tree_free(tree);

	/* Create a big tree and free it */
	tree = create_tree();
	avl_tree_free(tree);
}

void test_avl_tree_lookup(void)
{
	AVLTree *tree;
	int i;
	int *value;

	/* Create a tree and look up all values */
	tree = create_tree();

	for (i = 0; i < NUM_TEST_VALUES; ++i) {
		value = avl_tree_lookup(tree, &i);

		assert(value != NULL);
		assert(*value == i);
	}

	/* Test invalid values */
	i = -1;
	assert(avl_tree_lookup(tree, &i) == NULL);
	i = NUM_TEST_VALUES + 1;
	assert(avl_tree_lookup(tree, &i) == NULL);
	i = 8724897;
	assert(avl_tree_lookup(tree, &i) == NULL);

	avl_tree_free(tree);
}

void test_avl_tree_remove(void)
{
	AVLTree *tree;
	int i;
	int x, y, z;
	int value;
	unsigned int expected_entries;

	tree = create_tree();

	/* Try removing invalid entries */
	i = NUM_TEST_VALUES + 100;
	assert(avl_tree_remove(tree, &i) == 0);
	i = -1;
	assert(avl_tree_remove(tree, &i) == 0);

	/* Delete the nodes from the tree */
	expected_entries = NUM_TEST_VALUES;

	/* This looping arrangement causes nodes to be removed in a
	 * randomish fashion from all over the tree. */
	for (x = 0; x < 10; ++x) {
		for (y = 0; y < 10; ++y) {
			for (z = 0; z < 10; ++z) {
				value = z * 100 + (9 - y) * 10 + x;
				assert(avl_tree_remove(tree, &value) != 0);
				validate_tree(tree);
				expected_entries -= 1;
				assert(avl_tree_num_entries(tree) ==
				       expected_entries);
			}
		}
	}

	/* All entries removed, should be empty now */
	assert(avl_tree_root_node(tree) == NULL);

	avl_tree_free(tree);
}

void test_avl_tree_to_array(void)
{
	AVLTree *tree;
	int entries[] = {89, 23, 42, 4, 16, 15, 8, 99, 50, 30};
	int sorted[] = {4, 8, 15, 16, 23, 30, 42, 50, 89, 99};
	unsigned int num_entries = sizeof(entries) / sizeof(int);
	unsigned int i;
	int **array;

	/* Add all entries to the tree */
	tree = avl_tree_new((AVLTreeCompareFunc) int_compare);

	for (i = 0; i < num_entries; ++i) {
		avl_tree_insert(tree, &entries[i], NULL);
	}

	assert(avl_tree_num_entries(tree) == num_entries);

	/* Convert to an array and check the contents */
	array = (int **) avl_tree_to_array(tree);

	for (i = 0; i < num_entries; ++i) {
		assert(*array[i] == sorted[i]);
	}

	free(array);

	/* Test out of memory scenario */
	alloc_test_set_limit(0);

	array = (int **) avl_tree_to_array(tree);
	assert(array == NULL);
	validate_tree(tree);

	avl_tree_free(tree);
}

/* clang-format off */
static UnitTestFunction tests[] = {
	test_avl_tree_new,
	test_avl_tree_free,
	test_avl_tree_child,
	test_avl_tree_insert_lookup,
	test_avl_tree_lookup,
	test_avl_tree_remove,
	test_avl_tree_to_array,
	test_out_of_memory,
	NULL
};
/* clang-format on */

int main(int argc, char *argv[])
{
	run_tests(tests);
	return 0;
}