Index: uspace/lib/c/test/fibril/exit_hook.c
===================================================================
--- uspace/lib/c/test/fibril/exit_hook.c	(revision 25ee7ec5603baddad57692682d7109d5a7f9c0c8)
+++ uspace/lib/c/test/fibril/exit_hook.c	(revision af28af66b2f75b653b814d95c7e3b93389a559e6)
@@ -58,26 +58,45 @@
 }
 
-/*
- * 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);
- * }
- */
+static errno_t fibril_explicit_exit(void *_arg)
+{
+	fibril_add_exit_hook(exit_hook);
+	fibril_exit(ETIMEOUT);
+}
+
+PCUT_TEST(exit_hook_explicit_exit)
+{
+	value = 0;
+	fid_t other = fibril_create(fibril_explicit_exit, NULL);
+	fibril_start(other);
+
+	fibril_yield();
+
+	PCUT_ASSERT_INT_EQUALS(5, value);
+}
+
+#ifdef FIBRIL_KILL_HAS_BEEN_IMPLEMENTED
+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);
+}
+#endif // FIBRIL_KILL_HAS_BEEN_IMPLEMENTED
 
 PCUT_EXPORT(fibril_exit_hook);
Index: uspace/lib/posix/meson.build
===================================================================
--- uspace/lib/posix/meson.build	(revision 25ee7ec5603baddad57692682d7109d5a7f9c0c8)
+++ uspace/lib/posix/meson.build	(revision af28af66b2f75b653b814d95c7e3b93389a559e6)
@@ -61,4 +61,5 @@
 	'test/stdlib.c',
 	'test/unistd.c',
+	'test/pthread/keys.c',
 )
 
Index: uspace/lib/posix/test/main.c
===================================================================
--- uspace/lib/posix/test/main.c	(revision 25ee7ec5603baddad57692682d7109d5a7f9c0c8)
+++ uspace/lib/posix/test/main.c	(revision af28af66b2f75b653b814d95c7e3b93389a559e6)
@@ -34,4 +34,5 @@
 PCUT_IMPORT(stdlib);
 PCUT_IMPORT(unistd);
+PCUT_IMPORT(pthread_keys);
 
 PCUT_MAIN();
Index: uspace/lib/posix/test/pthread/keys.c
===================================================================
--- uspace/lib/posix/test/pthread/keys.c	(revision af28af66b2f75b653b814d95c7e3b93389a559e6)
+++ uspace/lib/posix/test/pthread/keys.c	(revision af28af66b2f75b653b814d95c7e3b93389a559e6)
@@ -0,0 +1,84 @@
+/*
+ * 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 <posix/pthread.h>
+#include <pcut/pcut.h>
+
+PCUT_INIT;
+
+PCUT_TEST_SUITE(pthread_keys);
+
+pthread_key_t key;
+int destructors_executed;
+
+static void destructor(void *_data)
+{
+	destructors_executed++;
+}
+
+static errno_t simple_fibril(void *_arg)
+{
+	PCUT_ASSERT_INT_EQUALS(0, pthread_setspecific(key, (void *) 0x0d9e));
+	PCUT_ASSERT_PTR_EQUALS((void *) 0x0d9e, pthread_getspecific(key));
+
+	for (int i = 0; i < 10; i++) {
+		fibril_yield();
+	}
+
+	return EOK;
+}
+
+PCUT_TEST(pthread_keys_basic)
+{
+	destructors_executed = 0;
+	PCUT_ASSERT_INT_EQUALS(0, pthread_key_create(&key, destructor));
+	PCUT_ASSERT_PTR_EQUALS(NULL, pthread_getspecific(key));
+
+	PCUT_ASSERT_INT_EQUALS(0, pthread_setspecific(key, (void *) 0x42));
+	PCUT_ASSERT_PTR_EQUALS((void *) 0x42, pthread_getspecific(key));
+
+	fid_t other = fibril_create(simple_fibril, NULL);
+	fibril_start(other);
+
+	for (int i = 0; i < 5; i++) {
+		fibril_yield();
+	}
+
+	PCUT_ASSERT_INT_EQUALS(0, destructors_executed);
+	PCUT_ASSERT_PTR_EQUALS((void *) 0x42, pthread_getspecific(key));
+
+	for (int i = 0; i < 10; i++) {
+		fibril_yield();
+	}
+
+	PCUT_ASSERT_INT_EQUALS(1, destructors_executed);
+	PCUT_ASSERT_PTR_EQUALS((void *) 0x42, pthread_getspecific(key));
+}
+
+PCUT_EXPORT(pthread_keys);