Write more redbean unit tests

- Fix DescribeSigset()
- Introduce new unix.rmrf() API
- Fix redbean sigaction() doc example code
- Fix unix.sigaction() w/ more than two args
- Improve redbean re module API (non-breaking)
- Enhance Lua with Python string multiplication
- Make third parameter of unix.socket() default to 0

test/libc/intrin/describesigset_test.c

@@ -0,0 +1,38 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2022 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ Permission to use, copy, modify, and/or distribute this software for         │
+│ any purpose with or without fee is hereby granted, provided that the         │
+│ above copyright notice and this permission notice appear in all copies.      │
+│                                                                              │
+│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
+│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
+│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
+│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
+│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
+│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
+│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
+│ PERFORMANCE OF THIS SOFTWARE.                                                │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/calls/struct/sigset.h"
+#include "libc/intrin/describeflags.internal.h"
+#include "libc/sysv/consts/sig.h"
+#include "libc/testlib/testlib.h"
+
+TEST(DescribeSigset, present) {
+  sigset_t ss;
+  sigemptyset(&ss);
+  sigaddset(&ss, SIGINT);
+  sigaddset(&ss, SIGUSR1);
+  EXPECT_STREQ("{INT,USR1}", DescribeSigset(0, &ss));
+}
+
+TEST(DescribeSigset, absent) {
+  sigset_t ss;
+  sigfillset(&ss);
+  sigdelset(&ss, SIGINT);
+  sigdelset(&ss, SIGUSR1);
+  EXPECT_STREQ("~{INT,USR1}", DescribeSigset(0, &ss));
+}