diff -r 3f324ea53152 -r 21840975d541 tests/test_tree.c
--- a/tests/test_tree.c	Wed Feb 14 22:32:13 2024 +0100
+++ b/tests/test_tree.c	Thu Feb 15 21:54:43 2024 +0100
@@ -42,6 +42,8 @@
     offsetof(tree_node, parent), offsetof(tree_node, children), \
     offsetof(tree_node, prev), offsetof(tree_node, next)
 
+#define tree_child_list offsetof(tree_node, children),offsetof(tree_node, next)
+
 CX_TEST(test_tree_link_new_child) {
     tree_node parent = {0};
     tree_node child = {0};
@@ -160,6 +162,94 @@
     }
 }
 
+static int test_tree_search_function(void const *n, void const *d) {
+    tree_node const *node = n;
+    int data = *((int const*)d);
+
+    if (data < node->data) return -1;
+    else if (data == node->data) return 0;
+    else return data - node->data;
+}
+
+CX_TEST(test_tree_search) {
+    tree_node root = {0};
+    tree_node a = {0};
+    tree_node b = {0};
+    tree_node c = {0};
+    tree_node aa = {0};
+    tree_node ab = {0};
+    tree_node ba = {0};
+    tree_node ca = {0};
+    tree_node cb = {0};
+    tree_node cc = {0};
+    tree_node cba = {0};
+
+    int testdata[] = {0, 10, 14, 18, 20, 25, 30, 32, 34, 36, 40};
+    tree_node* testnodes[] = {&root, &a, &aa, &ab, &b, &ba, &c, &ca, &cb, &cba, &cc};
+
+    for (unsigned i = 0 ; i <= 10 ; i++) {
+        testnodes[i]->data = testdata[i];
+    }
+
+    cx_tree_link(&root, &a, tree_node_layout);
+    cx_tree_link(&root, &b, tree_node_layout);
+    cx_tree_link(&root, &c, tree_node_layout);
+
+    cx_tree_link(&a, &aa, tree_node_layout);
+    cx_tree_link(&a, &ab, tree_node_layout);
+
+    cx_tree_link(&b, &ba, tree_node_layout);
+
+    cx_tree_link(&c, &ca, tree_node_layout);
+    cx_tree_link(&c, &cb, tree_node_layout);
+    cx_tree_link(&c, &cc, tree_node_layout);
+
+    cx_tree_link(&cb, &cba, tree_node_layout);
+
+    int s;
+    int r;
+    tree_node *n;
+    CX_TEST_DO {
+        for (unsigned i = 0 ; i <= 10 ; i++) {
+            s = testdata[i];
+            r = cx_tree_search(&root, &s, test_tree_search_function,
+                               (void **) &n, tree_child_list);
+            CX_TEST_ASSERT(r == 0);
+            CX_TEST_ASSERT(n == testnodes[i]);
+        }
+
+        s = -5;
+        r = cx_tree_search(&root, &s, test_tree_search_function,
+                           (void **) &n, tree_child_list);
+        CX_TEST_ASSERT(r < 0);
+        CX_TEST_ASSERT(n == NULL);
+
+        s = 26;
+        r = cx_tree_search(&root, &s, test_tree_search_function,
+                           (void **) &n, tree_child_list);
+        CX_TEST_ASSERT(r > 0);
+        CX_TEST_ASSERT(n == &ba);
+
+        s = 35;
+        r = cx_tree_search(&root, &s, test_tree_search_function,
+                           (void **) &n, tree_child_list);
+        CX_TEST_ASSERT(r > 0);
+        CX_TEST_ASSERT(n == &cb);
+
+        s = 38;
+        r = cx_tree_search(&root, &s, test_tree_search_function,
+                           (void **) &n, tree_child_list);
+        CX_TEST_ASSERT(r > 0);
+        CX_TEST_ASSERT(n == &cba);
+
+        s = 42;
+        r = cx_tree_search(&root, &s, test_tree_search_function,
+                           (void **) &n, tree_child_list);
+        CX_TEST_ASSERT(r > 0);
+        CX_TEST_ASSERT(n == &cc);
+    }
+}
+
 CxTestSuite *cx_test_suite_tree_low_level(void) {
     CxTestSuite *suite = cx_test_suite_new("tree (low level)");
 
@@ -167,6 +257,7 @@
     cx_test_register(suite, test_tree_link_add_child);
     cx_test_register(suite, test_tree_link_move_to_other_parent);
     cx_test_register(suite, test_tree_unlink);
+    cx_test_register(suite, test_tree_search);
 
     return suite;
 }