diff --git a/quic/test_tools/mock_random.h b/quic/test_tools/mock_random.h
new file mode 100644
index 0000000..e8229c0
--- /dev/null
+++ b/quic/test_tools/mock_random.h
@@ -0,0 +1,40 @@
+// Copyright (c) 2012 The Chromium 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 QUICHE_QUIC_TEST_TOOLS_MOCK_RANDOM_H_
+#define QUICHE_QUIC_TEST_TOOLS_MOCK_RANDOM_H_
+
+#include "base/macros.h"
+#include "net/third_party/quiche/src/quic/core/crypto/quic_random.h"
+
+namespace quic {
+namespace test {
+
+class MockRandom : public QuicRandom {
+ public:
+  // Initializes base_ to 0xDEADBEEF.
+  MockRandom();
+  explicit MockRandom(uint32_t base);
+  MockRandom(const MockRandom&) = delete;
+  MockRandom& operator=(const MockRandom&) = delete;
+
+  // QuicRandom:
+  // Fills the |data| buffer with a repeating byte, initially 'r'.
+  void RandBytes(void* data, size_t len) override;
+  // Returns base + the current increment.
+  uint64_t RandUint64() override;
+
+  // ChangeValue increments |increment_|. This causes the value returned by
+  // |RandUint64| and the byte that |RandBytes| fills with, to change.
+  void ChangeValue();
+
+ private:
+  uint32_t base_;
+  uint8_t increment_;
+};
+
+}  // namespace test
+}  // namespace quic
+
+#endif  // QUICHE_QUIC_TEST_TOOLS_MOCK_RANDOM_H_