Begin incorporating Python unit tests into build

We now build a separate APE binary for each test so they can run in
parallel. We've got 148 tests running fast and stable so far.

third_party/python/harness.c

@@ -0,0 +1,164 @@
+/*-*- 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 2021 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/calls.h"
+#include "libc/calls/copyfile.h"
+#include "libc/calls/sigbits.h"
+#include "libc/dce.h"
+#include "libc/errno.h"
+#include "libc/mem/mem.h"
+#include "libc/runtime/runtime.h"
+#include "libc/stdio/append.internal.h"
+#include "libc/stdio/stdio.h"
+#include "libc/sysv/consts/o.h"
+#include "libc/sysv/consts/sig.h"
+#include "libc/x/x.h"
+#include "third_party/getopt/getopt.h"
+
+#define MANUAL \
+  "\
+SYNOPSIS\n\
+\n\
+  harness.com [FLAGS] COMMAND [ARGS...]\n\
+\n\
+OVERVIEW\n\
+\n\
+  Python Test Hardness\n\
+\n\
+FLAGS\n\
+\n\
+  -n           do nothing (used to prime the executable)\n\
+  -h           print help\n\
+\n"
+
+bool FileExistsAndIsNewerThan(const char *filepath, const char *thanpath) {
+  struct stat st1, st2;
+  if (stat(filepath, &st1) == -1) return false;
+  if (stat(thanpath, &st2) == -1) return false;
+  if (st1.st_mtim.tv_sec < st2.st_mtim.tv_sec) return false;
+  if (st1.st_mtim.tv_sec > st2.st_mtim.tv_sec) return true;
+  return st1.st_mtim.tv_nsec >= st2.st_mtim.tv_nsec;
+}
+
+int main(int argc, char *argv[]) {
+  size_t got;
+  ssize_t rc;
+  bool failed;
+  sigset_t mask, savemask;
+  int ws, opt, pid, exitcode, pipefds[2];
+  char *cmd, *output, *comdbg, *cachedcmd, *originalcmd, buf[512];
+  while ((opt = getopt(argc, argv, "hn")) != -1) {
+    switch (opt) {
+      case 'n':
+        exit(0);
+      case 'h':
+        fputs(MANUAL, stdout);
+        exit(0);
+      default:
+        fputs(MANUAL, stderr);
+        exit(1);
+    }
+  }
+  if (optind == argc) {
+    fputs("error: missing arguments\n", stderr);
+    exit(1);
+  }
+  cmd = argv[optind];
+  originalcmd = NULL;
+  cachedcmd = NULL;
+  if (!IsWindows() && endswith(cmd, ".com")) {
+    comdbg = xstrcat(cmd, ".dbg");
+    cachedcmd = xstrcat("o/", cmd);
+    if (fileexists(comdbg)) {
+      setenv("COMDBG", comdbg, 1);
+    }
+    if (FileExistsAndIsNewerThan(cachedcmd, cmd)) {
+      cmd = cachedcmd;
+    } else {
+      if (startswith(cmd, "o/")) {
+        cachedcmd = NULL;
+      }
+      originalcmd = cmd;
+      cmd = xasprintf("%s.tmp.%d", originalcmd, getpid());
+      copyfile(originalcmd, cmd, 0);
+    }
+  }
+  sigfillset(&mask);
+  if (pipe2(pipefds, O_CLOEXEC) == -1) exit(errno);
+  close(0);
+  sigprocmask(SIG_BLOCK, &mask, &savemask);
+  if ((pid = vfork()) == -1) exit(errno);
+  if (!pid) {
+    open("/dev/null", O_RDONLY);
+    dup2(pipefds[1], 1);
+    dup2(pipefds[1], 2);
+    sigprocmask(SIG_SETMASK, &savemask, 0);
+    execve(cmd, argv + 1, environ);
+    _exit(127);
+  }
+  close(pipefds[1]);
+  output = 0;
+  failed = false;
+  appends(&output, "");
+  for (;;) {
+    if ((rc = read(pipefds[0], buf, sizeof(buf))) != -1) {
+      if ((got = rc)) {
+        appendd(&output, buf, got);
+      } else {
+        break;
+      }
+    } else {
+      appendf(&output, "error: %s read() failed %m\n", cmd);
+      failed = true;
+      break;
+    }
+  }
+  close(pipefds[0]);
+  rc = wait4(pid, &ws, 0, 0);
+  if (originalcmd) {
+    if (cachedcmd && WIFEXITED(ws) && !WEXITSTATUS(ws)) {
+      makedirs(xdirname(cachedcmd), 0755);
+      rename(cmd, cachedcmd);
+    } else {
+      unlink(cmd);
+    }
+  }
+  if (rc != -1) {
+    if (WIFEXITED(ws)) {
+      if (!WEXITSTATUS(ws)) {
+        if (!failed) {
+          return 0;
+        } else {
+          exitcode = 77;
+        }
+      } else {
+        exitcode = WEXITSTATUS(ws);
+        appendf(&output, "error: %s exited with %d\n", cmd, exitcode);
+      }
+    } else {
+      appendf(&output, "error: %s terminated by %s\n", cmd,
+              strsignal(WTERMSIG(ws)));
+      exitcode = 128 + WTERMSIG(ws);
+    }
+  } else {
+    appendf(&output, "error: %s wait4() failed %m\n", cmd);
+    exitcode = 1;
+  }
+  xwrite(2, output, appendz(output).i);
+  return exitcode;
+}