Index: uspace/lib/c/test/fibril/exit_hook.c
===================================================================
--- uspace/lib/c/test/fibril/exit_hook.c	(revision 7064e71fb59500fe3cad795c283fcc654d8cec8b)
+++ uspace/lib/c/test/fibril/exit_hook.c	(revision 7064e71fb59500fe3cad795c283fcc654d8cec8b)
@@ -0,0 +1,81 @@
+/*
+ * Copyright (c) 2025 Matej Volf
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ * - Redistributions in binary form must reproduce the above copyright
+ *   notice, this list of conditions and the following disclaimer in the
+ *   documentation and/or other materials provided with the distribution.
+ * - The name of the author may not be used to endorse or promote products
+ *   derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <fibril.h>
+#include <pcut/pcut.h>
+
+PCUT_INIT;
+
+PCUT_TEST_SUITE(fibril_exit_hook);
+
+static int value;
+
+static void exit_hook(void) {
+    value = 5;
+}
+
+static errno_t fibril_basic(void* _arg) {
+    fibril_add_exit_hook(exit_hook);
+    return EOK;
+}
+
+PCUT_TEST(exit_hook_basic) {
+    value = 0;
+    fid_t other = fibril_create(fibril_basic, NULL);
+    fibril_start(other);
+
+    fibril_yield();
+
+    PCUT_ASSERT_INT_EQUALS(5, value);
+}
+
+/*
+static errno_t fibril_to_be_killed(void* _arg) {
+    fibril_add_exit_hook(exit_hook);
+
+    while (true)
+        firbil_yield();
+
+    assert(0 && "unreachable");
+}
+
+PCUT_TEST(exit_hook_kill) {
+    value = 0;
+    fid_t other = fibril_create(fibril_to_be_killed, NULL);
+    fibril_start(other);
+
+    fibril_yield();
+
+    fibril_kill(other); // anything like this doesn't exist yet
+
+    PCUT_ASSERT_INT_EQUALS(5, value);
+}
+*/
+
+
+PCUT_EXPORT(fibril_exit_hook);
Index: uspace/lib/c/test/main.c
===================================================================
--- uspace/lib/c/test/main.c	(revision 9c40b834b80ea3b3dd4beec40d348609791267f7)
+++ uspace/lib/c/test/main.c	(revision 7064e71fb59500fe3cad795c283fcc654d8cec8b)
@@ -38,4 +38,5 @@
 PCUT_IMPORT(double_to_str);
 PCUT_IMPORT(fibril_timer);
+PCUT_IMPORT(fibril_exit_hook);
 PCUT_IMPORT(getopt);
 PCUT_IMPORT(gsort);