diff --git a/src/demangle_unittest.sh b/src/demangle_unittest.sh
new file mode 100755
index 0000000..91deee2
--- /dev/null
+++ b/src/demangle_unittest.sh
@@ -0,0 +1,95 @@
+#! /bin/sh
+#
+# Copyright (c) 2006, 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
+#
+# Unit tests for demangle.c with a real binary.
+
+set -e
+
+die () {
+    echo $1
+    exit 1
+}
+
+BINDIR=".libs"
+LIBGLOG="$BINDIR/libglog.so"
+
+DEMANGLER="$BINDIR/demangle_unittest"
+
+if test -e "$DEMANGLER"; then
+  # We need shared object.
+  export LD_LIBRARY_PATH=$BINDIR
+  export DYLD_LIBRARY_PATH=$BINDIR
+else
+  # For windows
+  DEMANGLER="./demangle_unittest.exe"
+  if ! test -e "$DEMANGLER"; then
+    echo "We coundn't find demangle_unittest binary."
+    exit 1
+  fi
+fi
+
+# Extract C++ mangled symbols from libbase.so.
+NM_OUTPUT="demangle.nm"
+nm "$LIBGLOG" | perl -nle 'print $1 if /\s(_Z\S+$)/' > "$NM_OUTPUT"
+
+# Check if mangled symbols exist. If there are none, we quit.
+# The binary is more likely compiled with GCC 2.95 or something old.
+if ! grep --quiet '^_Z' "$NM_OUTPUT"; then
+    echo "PASS"
+    exit 0
+fi
+
+# Demangle the symbols using our demangler.
+DM_OUTPUT="demangle.dm"
+GLOG_demangle_filter=1 "$DEMANGLER" --demangle_filter < "$NM_OUTPUT" > "$DM_OUTPUT"
+
+# Calculate the numbers of lines.
+NM_LINES=`wc -l "$NM_OUTPUT" | awk '{ print $1 }'`
+DM_LINES=`wc -l "$DM_OUTPUT" | awk '{ print $1 }'`
+
+# Compare the numbers of lines.  They must be the same.
+if test "$NM_LINES" != "$DM_LINES"; then
+    die "$NM_OUTPUT and $DM_OUTPUT don't have the same numbers of lines"
+fi
+
+# Check if mangled symbols exist.  They must not exist.
+if grep --quiet '^_Z' "$DM_OUTPUT"; then
+    MANGLED=`grep '^_Z' "$DM_OUTPUT" | wc -l | awk '{ print \$1 }'`
+    echo "Mangled symbols ($MANGLED out of $NM_LINES) found in $DM_OUTPUT:"
+    grep '^_Z' "$DM_OUTPUT"
+    die "Mangled symbols ($MANGLED out of $NM_LINES) found in $DM_OUTPUT"
+fi
+
+# All C++ symbols are demangled successfully.
+echo "PASS"
+exit 0