Complete preorder traversal of a binary tree

1 files changed, 103 insertions, 0 deletions

diff --git a/src/02/01/binary_tree_test.c b/src/02/01/binary_tree_test.c
new file mode 100644
index 0000000..bbd7166
--- /dev/null
+++ b/src/02/01/binary_tree_test.c
@@ -0,0 +1,103 @@
+#include "binary_tree.h"
+#include <cgreen/cgreen.h>
+#include <string.h>
+
+int visited[256];
+int visited_count;
+
+Describe(BinaryTree);
+BeforeEach(BinaryTree) {
+  memset(visited, 0, sizeof(visited));
+  visited_count = 0;
+}
+AfterEach(BinaryTree) {}
+
+void visitor(Node *node) {
+  visited[visited_count] = node->data;
+  visited_count++;
+}
+
+Ensure(BinaryTree, when_traversing_in_preorder_when_the_tree_is_empty) {
+  preorder_next(NULL, visitor);
+
+  assert_that(visited_count, is_equal_to(0));
+}
+
+Ensure(BinaryTree, when_traversing_in_preorder_when_the_tree_has_a_single_node) {
+  Node *node = initialize(100);
+
+  preorder_next(node, visitor);
+
+  assert_that(visited_count, is_equal_to(1));
+  assert_that(visited[0], is_equal_to(100));
+}
+
+Ensure(BinaryTree, when_traversing_in_preorder_when_the_tree_has_a_left_node) {
+  Node *node = initialize(100);
+  node->left = initialize(200);
+
+  preorder_next(node, visitor);
+
+  assert_that(visited_count, is_equal_to(2));
+  assert_that(visited[0], is_equal_to(100));
+  assert_that(visited[1], is_equal_to(200));
+}
+
+Ensure(BinaryTree, when_traversing_in_preorder_when_the_tree_has_a_right_node) {
+  Node *node = initialize(100);
+  node->right = initialize(300);
+
+  preorder_next(node, visitor);
+
+  assert_that(visited_count, is_equal_to(2));
+  assert_that(visited[0], is_equal_to(100));
+  assert_that(visited[1], is_equal_to(300));
+}
+
+Ensure(BinaryTree, when_traversing_in_preorder_when_the_tree_has_a_left_and_right_node) {
+  Node *node = initialize(100);
+  node->left = initialize(200);
+  node->right = initialize(300);
+
+  preorder_next(node, visitor);
+
+  assert_that(visited_count, is_equal_to(3));
+  assert_that(visited[0], is_equal_to(100));
+  assert_that(visited[1], is_equal_to(200));
+  assert_that(visited[2], is_equal_to(300));
+}
+
+Ensure(BinaryTree, when_traversing_in_preorder_when_the_tree_has_multiple_levels) {
+  Node *node = initialize(100);
+  node->left = initialize(200);
+  node->right = initialize(300);
+
+  node->left->left = initialize(400);
+  node->left->right = initialize(500);
+
+  preorder_next(node, visitor);
+
+  assert_that(visited_count, is_equal_to(5));
+  assert_that(visited[0], is_equal_to(100));
+  assert_that(visited[1], is_equal_to(200));
+  assert_that(visited[2], is_equal_to(400));
+  assert_that(visited[3], is_equal_to(500));
+  assert_that(visited[4], is_equal_to(300));
+}
+
+TestSuite *binary_tree_tests() {
+  TestSuite *suite = create_test_suite();
+
+  add_test_with_context(suite, BinaryTree, when_traversing_in_preorder_when_the_tree_is_empty);
+  add_test_with_context(suite, BinaryTree, when_traversing_in_preorder_when_the_tree_has_a_single_node);
+  add_test_with_context(suite, BinaryTree, when_traversing_in_preorder_when_the_tree_has_a_left_node);
+  add_test_with_context(suite, BinaryTree, when_traversing_in_preorder_when_the_tree_has_a_right_node);
+
+  return suite;
+}
+
+int main(int argc, char **argv) {
+  TestSuite *suite = create_test_suite();
+  add_suite(suite, binary_tree_tests());
+  return run_test_suite(suite, create_text_reporter());
+}