diff --git a/certificate_checker_mock.h b/certificate_checker_mock.h
new file mode 100644
index 0000000..55668a1
--- /dev/null
+++ b/certificate_checker_mock.h
@@ -0,0 +1,26 @@
+// Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROMEOS_UPDATE_ENGINE_CERTIFICATE_CHECKER_MOCK_H_
+#define CHROMEOS_UPDATE_ENGINE_CERTIFICATE_CHECKER_MOCK_H_
+
+#include <gmock/gmock.h>
+#include <openssl/ssl.h>
+
+#include "update_engine/certificate_checker.h"
+
+namespace chromeos_update_engine {
+
+class OpenSSLWrapperMock : public OpenSSLWrapper {
+ public:
+  MOCK_CONST_METHOD4(GetCertificateDigest,
+                     bool(X509_STORE_CTX* x509_ctx,
+                          int* out_depth,
+                          unsigned int* out_digest_length,
+                          unsigned char* out_digest));
+};
+
+}  // namespace chromeos_update_engine
+
+#endif  // CHROMEOS_UPDATE_ENGINE_CERTIFICATE_CHECKER_MOCK_H_