Do a better job at faking simple challenge signatures.

chromeos/dbus/fake_cryptohome_client_unittest.cc

+// Copyright 2016 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.
+
+#include "chromeos/dbus/fake_cryptohome_client.h"
+
+#include <string>
+
+#include "base/bind.h"
+#include "base/bind_helpers.h"
+#include "base/run_loop.h"
+#include "chromeos/cryptohome/attestation.pb.h"
+#include "chromeos/cryptohome/cryptohome_parameters.h"
+#include "testing/gmock/include/gmock/gmock.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+using ::testing::_;
+using ::testing::SaveArg;
+
+namespace chromeos {
+
+class FakeCryptohomeClientTest : public ::testing::Test {
+ public:
+  FakeCryptohomeClientTest() : weak_ptr_factory_(this) {
+    async_method_callback_ =
+        base::Bind(&FakeCryptohomeClientTest::MockHandleAsyncMethodCallback,
+                   weak_ptr_factory_.GetWeakPtr());
+    fake_cryptohome_client_.SetAsyncCallStatusHandlers(
+        base::Bind(
+            &FakeCryptohomeClientTest::MockHandleAsyncMethodResultResponse,
+            weak_ptr_factory_.GetWeakPtr()),
+        base::Bind(&FakeCryptohomeClientTest::MockHandleAsyncMethodDataResponse,
+                   weak_ptr_factory_.GetWeakPtr()));
+  }
+
+  void Run() {

[xiyuan, 2016/09/06 22:32:32]

nit: We probably can get rid of this method and just do
base::RunLoop().RunUntilIdle(); where this method is called,


e.g.
https://cs.chromium.org/chromium/src/dbus/bus_unittest.cc?rcl=0&l=341

[The one and only Dr. Crash, 2016/09/07 02:43:47]

Sure.

+    base::RunLoop run_loop;
+    run_loop.RunUntilIdle();
+  }
+
+  MOCK_METHOD1(MockHandleAsyncMethodCallback, void(int));
+  MOCK_METHOD3(MockHandleAsyncMethodResultResponse, void(int, bool, int));
+  MOCK_METHOD3(MockHandleAsyncMethodDataResponse,
+               void(int, bool, const std::string&));
+
+ protected:
+  base::MessageLoop message_loop_;
+
+  FakeCryptohomeClient fake_cryptohome_client_;
+  CryptohomeClient::AsyncMethodCallback async_method_callback_;
+
+  base::WeakPtrFactory<FakeCryptohomeClientTest> weak_ptr_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(FakeCryptohomeClientTest);
+};
+
+TEST_F(FakeCryptohomeClientTest, SignSimpleChallenge) {
+  const std::string challenge{"challenge"};
+
+  EXPECT_CALL(*this, MockHandleAsyncMethodCallback(_));
+
+  std::string return_data;
+  EXPECT_CALL(*this, MockHandleAsyncMethodDataResponse(_, true, _))
+      .WillOnce(SaveArg<2>(&return_data));
+
+  cryptohome::Identification cryptohome_id;
+  fake_cryptohome_client_.TpmAttestationSignSimpleChallenge(
+      attestation::AttestationKeyType::KEY_DEVICE, cryptohome_id, "key_name",
+      challenge, async_method_callback_);
+
+  Run();
+
+  cryptohome::SignedData signed_data;
+  ASSERT_TRUE(signed_data.ParseFromString(return_data));
+  ASSERT_EQ(static_cast<size_t>(20),
+            signed_data.data().size() - challenge.size());
+  ASSERT_EQ(challenge,
+            signed_data.data().substr(0, signed_data.data().size() - 20));
+}
+
+}  // namespace cryptohome