tests/tree.c: Add test for tree_contains()

After writing the test, a failing case made me notice that the
comparison was reversed, and I then fixed the implementation :)

1 files changed, 1 insertions, 1 deletions

diff --git a/src/tree.c b/src/tree.c
index fccf209..f19eae2 100644
--- a/src/tree.c
+++ b/src/tree.c
@@ -191,7 +191,7 @@ tree_contains(const struct Tree *const t, const void *const value) {
 	const int cmp = memcmp(value, t->value, t->value_size);
 	if (cmp == 0) {
 		return true;
-	} else if (cmp > 0) {
+	} else if (cmp < 0) {
 		if (t->left == NULL) {
 			return false;
 		}