test(kernel): cover errno return contracts

kernel/selftest/page_table.c

@@ -1,6 +1,7 @@
 #include <stdint.h>
 
 #include <tianole/early_log.h>
+#include <tianole/errno.h>
 #include <tianole/mm.h>
 
 #include "arch/x86/mm/page_table.h"
@@ -20,10 +21,26 @@ void page_table_selftest(void)
 
 	page_tables_init();
 
+	if (map_page(TEST_VIRTUAL_PAGE + 1, page, PAGE_WRITABLE) != -EINVAL) {
+		panic("page table selftest unaligned map errno failed");
+	}
+
+	if (virt_to_phys(TEST_VIRTUAL_PAGE, 0) != -EINVAL) {
+		panic("page table selftest null output errno failed");
+	}
+
+	if (virt_to_phys(TEST_VIRTUAL_PAGE, &resolved) != -ENOENT) {
+		panic("page table selftest missing resolve errno failed");
+	}
+
 	if (map_page(TEST_VIRTUAL_PAGE, page, PAGE_WRITABLE) != 0) {
 		panic("page table selftest map failed");
 	}
 
+	if (map_page(TEST_VIRTUAL_PAGE, page, PAGE_WRITABLE) != -EEXIST) {
+		panic("page table selftest duplicate map errno failed");
+	}
+
 	if (virt_to_phys(TEST_VIRTUAL_PAGE, &resolved) != 0 ||
 		resolved != page) {
 		panic("page table selftest resolve failed");
@@ -38,6 +55,10 @@ void page_table_selftest(void)
 		panic("page table selftest unmap failed");
 	}
 
+	if (unmap_page(TEST_VIRTUAL_PAGE) != -ENOENT) {
+		panic("page table selftest missing unmap errno failed");
+	}
+
 	free_page(page);
 	early_log_puts("page table selftest ok\n");
 }

kernel/selftest/sched.c

@@ -14,9 +14,16 @@ static void thread_selftest_entry(void *arg)
 	(void)arg;
 }
 
+static int selftest_condition_false(void *arg)
+{
+	(void)arg;
+	return 0;
+}
+
 void sched_selftest(void)
 {
 	struct spinlock test_lock;
+	struct wait_queue test_wait_queue;
 	struct thread *first =
 		kernel_thread_create("worker-a", thread_selftest_entry, 0);
 	struct thread *second =
@@ -47,6 +54,15 @@ void sched_selftest(void)
 	spin_lock_irqsave(&test_lock, &flags);
 	spin_unlock_irqrestore(&test_lock, flags);
 
+	wait_queue_init(&test_wait_queue);
+	if (wait_queue_wait(0, selftest_condition_false, 0) != -EINVAL) {
+		panic("wait queue selftest null queue errno failed");
+	}
+
+	if (wait_queue_wait(&test_wait_queue, 0, 0) != -EINVAL) {
+		panic("wait queue selftest null condition errno failed");
+	}
+
 	early_log_puts("kernel thread selftest ok\n");
 }
 
@@ -127,6 +143,12 @@ static void timeout_wait_demo_waiter(void *arg)
 	(void)arg;
 
 	early_log_puts("timeout waiter sleeping\n");
+	if (wait_queue_wait_timeout(
+		    &timeout_wait_queue, condition_is_ready, &never_ready, 0) !=
+		-ETIMEDOUT) {
+		panic("timeout wait zero tick errno failed");
+	}
+
 	if (wait_queue_wait_timeout(
 		    &timeout_wait_queue, condition_is_ready, &never_ready, 3) !=
 		-ETIMEDOUT) {