diff --git a/src/signalhandler_unittest.cc b/src/signalhandler_unittest.cc
new file mode 100644
index 0000000..36d957b
--- /dev/null
+++ b/src/signalhandler_unittest.cc
@@ -0,0 +1,112 @@
+// Copyright (c) 2008, Google Inc.
+// 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.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "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 COPYRIGHT
+// OWNER OR CONTRIBUTORS 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.
+//
+// Author: Satoru Takabayashi
+//
+// This is a helper binary for testing signalhandler.cc.  The actual test
+// is done in signalhandler_unittest.sh.
+
+#include "utilities.h"
+
+#if defined(HAVE_PTHREAD)
+# include <pthread.h>
+#endif
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string>
+#include "glog/logging.h"
+
+#ifdef HAVE_LIB_GFLAGS
+#include <gflags/gflags.h>
+using namespace GFLAGS_NAMESPACE;
+#endif
+
+using namespace GOOGLE_NAMESPACE;
+
+static void* DieInThread(void*) {
+  // We assume pthread_t is an integral number or a pointer, rather
+  // than a complex struct.  In some environments, pthread_self()
+  // returns an uint64 but in some other environments pthread_self()
+  // returns a pointer.  Hence we use C-style cast here, rather than
+  // reinterpret/static_cast, to support both types of environments.
+  fprintf(stderr, "0x%lx is dying\n", (long)pthread_self());
+  // Use volatile to prevent from these to be optimized away.
+  volatile int a = 0;
+  volatile int b = 1 / a;
+  fprintf(stderr, "We should have died: b=%d\n", b);
+  return NULL;
+}
+
+static void WriteToStdout(const char* data, int size) {
+  if (write(STDOUT_FILENO, data, size) < 0) {
+    // Ignore errors.
+  }
+}
+
+int main(int argc, char **argv) {
+#if defined(HAVE_STACKTRACE) && defined(HAVE_SYMBOLIZE)
+  InitGoogleLogging(argv[0]);
+#ifdef HAVE_LIB_GFLAGS
+  ParseCommandLineFlags(&argc, &argv, true);
+#endif
+  InstallFailureSignalHandler();
+  const std::string command = argc > 1 ? argv[1] : "none";
+  if (command == "segv") {
+    // We'll check if this is outputted.
+    LOG(INFO) << "create the log file";
+    LOG(INFO) << "a message before segv";
+    // We assume 0xDEAD is not writable.
+    int *a = (int*)0xDEAD;
+    *a = 0;
+  } else if (command == "loop") {
+    fprintf(stderr, "looping\n");
+    while (true);
+  } else if (command == "die_in_thread") {
+#if defined(HAVE_PTHREAD)
+    pthread_t thread;
+    pthread_create(&thread, NULL, &DieInThread, NULL);
+    pthread_join(thread, NULL);
+#else
+    fprintf(stderr, "no pthread\n");
+    return 1;
+#endif
+  } else if (command == "dump_to_stdout") {
+    InstallFailureWriter(WriteToStdout);
+    abort();
+  } else if (command == "installed") {
+    fprintf(stderr, "signal handler installed: %s\n",
+        IsFailureSignalHandlerInstalled() ? "true" : "false");
+  } else {
+    // Tell the shell script
+    puts("OK");
+  }
+#endif
+  return 0;
+}