diff --git a/test/test-error.c b/test/test-error.c
new file mode 100644
index 0000000..9096516
--- /dev/null
+++ b/test/test-error.c
@@ -0,0 +1,67 @@
+#include <errno.h>
+#include <stdbool.h>
+#include <stdlib.h>
+
+#include "test-util.h"
+#include "util.h"
+#include "wepoll.h"
+#include "win.h"
+
+static void check_error(bool did_fail,
+                        errno_t errno_value,
+                        DWORD last_error_value) {
+  check(did_fail);
+  check(errno == errno_value);
+  check(GetLastError() == last_error_value);
+}
+
+int main(void) {
+  const HANDLE bad_value = (HANDLE) 0xbadbad;
+  const HANDLE bad_type = CreateEventW(NULL, FALSE, FALSE, NULL);
+  check(bad_type != NULL && bad_type != INVALID_HANDLE_VALUE);
+
+  {
+    /* Test epoll_create() errors. */
+    HANDLE h;
+    h = epoll_create(-1);
+    check_error(h == NULL, EINVAL, ERROR_INVALID_PARAMETER);
+    h = epoll_create(0);
+    check_error(h == NULL, EINVAL, ERROR_INVALID_PARAMETER);
+  }
+
+  {
+    /* Test epoll_create1() errors. */
+    HANDLE h;
+    h = epoll_create1(-1);
+    check_error(h == NULL, EINVAL, ERROR_INVALID_PARAMETER);
+    h = epoll_create1(19);
+    check_error(h == NULL, EINVAL, ERROR_INVALID_PARAMETER);
+  }
+
+  {
+    /* Test epoll_close() errors. */
+    int r;
+    r = epoll_close(NULL);
+    check_error(r == -1, EBADF, ERROR_INVALID_HANDLE);
+    r = epoll_close(INVALID_HANDLE_VALUE);
+    check_error(r == -1, EBADF, ERROR_INVALID_HANDLE);
+    r = epoll_close(bad_value);
+    check_error(r == -1, EBADF, ERROR_INVALID_HANDLE);
+    r = epoll_close(bad_type);
+    check_error(r == -1, EINVAL, ERROR_INVALID_PARAMETER);
+  }
+
+  {
+      /* Test epoll_ctl() errors. */
+      /* TODO. */
+  }
+
+  {
+    /* Test epoll_wait() errors. */
+    /* TODO. */
+  }
+
+  CloseHandle(bad_type);
+
+  return 0;
+}