diff --git a/tools/cpp-define-generator/make_header_test.py b/tools/cpp-define-generator/make_header_test.py
new file mode 100755
index 0000000..eec1c68
--- /dev/null
+++ b/tools/cpp-define-generator/make_header_test.py
@@ -0,0 +1,53 @@
+#!/usr/bin/env python
+#
+# Copyright (C) 2018 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import unittest
+import make_header
+
+test_input = r'''
+// Check that the various other assembly lines are ignored.
+.globl  _Z49AsmDefineHelperFor_MIRROR_OBJECT_LOCK_WORD_OFFSETv
+.type   _Z49AsmDefineHelperFor_MIRROR_OBJECT_LOCK_WORD_OFFSETv,%function
+.ascii  ">>MIRROR_OBJECT_LOCK_WORD_OFFSET #4 #0<<"
+bx      lr
+
+// Check large positive 32-bit constant.
+.ascii  ">>OBJECT_ALIGNMENT_MASK_TOGGLED #4294967288 #0<<"
+
+// Check large positive 64-bit constant (it overflows into negative value).
+.ascii  ">>OBJECT_ALIGNMENT_MASK_TOGGLED64 #-8 #0<<"
+
+// Check negative constant.
+.ascii  ">>JIT_CHECK_OSR #-1 #1<<"
+'''
+
+test_output = r'''
+#define JIT_CHECK_OSR -0x1
+#define JIT_CHECK_OSR -0x1
+#define MIRROR_OBJECT_LOCK_WORD_OFFSET 0x4
+#define MIRROR_OBJECT_LOCK_WORD_OFFSET 0x4
+#define OBJECT_ALIGNMENT_MASK_TOGGLED 0xfffffff8
+#define OBJECT_ALIGNMENT_MASK_TOGGLED 0xfffffff8
+#define OBJECT_ALIGNMENT_MASK_TOGGLED64 0xfffffffffffffff8
+#define OBJECT_ALIGNMENT_MASK_TOGGLED64 0xfffffffffffffff8
+'''
+
+class CppDefineGeneratorTest(unittest.TestCase):
+  def test_convert(self):
+    self.assertEqual(test_output.strip(), make_header.convert(test_input))
+
+if __name__ == '__main__':
+  unittest.main()