Mojo C++ Bindings: Add helpers for bad message reporting

mojo/public/cpp/bindings/tests/report_bad_message_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 "base/bind.h"
+#include "base/callback.h"
+#include "base/macros.h"
+#include "base/message_loop/message_loop.h"
+#include "base/run_loop.h"
+#include "mojo/edk/embedder/embedder.h"
+#include "mojo/public/cpp/bindings/binding.h"
+#include "mojo/public/cpp/bindings/message.h"
+#include "mojo/public/interfaces/bindings/tests/test_bad_messages.mojom.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace mojo {
+namespace test {
+namespace {
+
+class TestBadMessagesImpl : public TestBadMessages {
+ public:
+  TestBadMessagesImpl() : binding_(this) {}
+  ~TestBadMessagesImpl() override {}
+
+  void BindImpl(TestBadMessagesRequest request) {
+    binding_.Bind(std::move(request));
+  }
+
+  const ReportBadMessageCallback& bad_message_callback() {
+    return bad_message_callback_;
+  }
+
+ private:
+  // TestBadMessages:
+  void RejectEventually(const RejectEventuallyCallback& callback) override {
+    bad_message_callback_ = GetBadMessageCallback();
+    callback.Run();
+  }
+
+  void RequestResponse(const RequestResponseCallback& callback) override {
+    callback.Run();
+  }
+
+  void RejectSync(const RejectSyncCallback& callback) override {
+    callback.Run();
+    ReportBadMessage("go away");
+  }
+
+  void RequestResponseSync(
+      const RequestResponseSyncCallback& callback) override {
+    callback.Run();
+  }
+
+  ReportBadMessageCallback bad_message_callback_;
+  mojo::Binding<TestBadMessages> binding_;
+
+  DISALLOW_COPY_AND_ASSIGN(TestBadMessagesImpl);
+};
+
+class ReportBadMessageTest : public testing::Test {
+ public:
+  ReportBadMessageTest() {}
+
+  void SetUp() override {
+    mojo::edk::SetDefaultProcessErrorCallback(
+        base::Bind(&ReportBadMessageTest::OnProcessError,
+                   base::Unretained(this)));
+
+    impl_.BindImpl(GetProxy(&proxy_));
+  }
+
+  TestBadMessages* proxy() { return proxy_.get(); }
+
+  TestBadMessagesImpl* impl() { return &impl_; }
+
+  void SetErrorHandler(const base::Closure& handler) {
+    error_handler_ = handler;
+  }
+
+ private:
+  void OnProcessError(const std::string& error) {
+    if (!error_handler_.is_null())
+      error_handler_.Run();
+  }
+
+  TestBadMessagesPtr proxy_;
+  TestBadMessagesImpl impl_;
+  base::Closure error_handler_;
+  base::MessageLoop message_loop;
+};
+
+TEST_F(ReportBadMessageTest, Request) {
+  // Verify that basic immediate error reporting works.
+  bool error = false;
+  SetErrorHandler(base::Bind([] (bool* flag) { *flag = true; }, &error));
+  EXPECT_TRUE(proxy()->RejectSync());
+  EXPECT_TRUE(error);
+}
+
+TEST_F(ReportBadMessageTest, RequestAsync) {
+  bool error = false;
+  SetErrorHandler(base::Bind([] (bool* flag) { *flag = true; }, &error));
+
+  // This should capture a bad message reporting callback in the impl.
+  base::RunLoop loop;
+  proxy()->RejectEventually(loop.QuitClosure());
+  loop.Run();
+
+  EXPECT_FALSE(error);
+
+  // Now we can run the callback and it should trigger a bad message report.
+  DCHECK(!impl()->bad_message_callback().is_null());
+  impl()->bad_message_callback().Run("bad!");
+  EXPECT_TRUE(error);
+}
+
+TEST_F(ReportBadMessageTest, Response) {
+  bool error = false;
+  SetErrorHandler(base::Bind([] (bool* flag) { *flag = true; }, &error));
+
+  base::RunLoop loop;
+  proxy()->RequestResponse(
+      base::Bind([] (const base::Closure& quit) {
+        // Report a bad message inside the response callback. This should
+        // trigger the error handler.
+        ReportBadMessage("no way!");
+        quit.Run();
+      },
+      loop.QuitClosure()));
+  loop.Run();
+
+  EXPECT_TRUE(error);
+}
+
+TEST_F(ReportBadMessageTest, ResponseAsync) {
+  bool error = false;
+  SetErrorHandler(base::Bind([] (bool* flag) { *flag = true; }, &error));
+
+  ReportBadMessageCallback bad_message_callback;
+  base::RunLoop loop;
+  proxy()->RequestResponse(
+      base::Bind([] (const base::Closure& quit,
+                     ReportBadMessageCallback* callback) {
+        // Capture the bad message callback inside the response callback.
+        *callback = GetBadMessageCallback();
+        quit.Run();
+      },
+      loop.QuitClosure(), &bad_message_callback));
+  loop.Run();
+
+  EXPECT_FALSE(error);
+
+  // Invoking this callback should report a bad message and trigger the error
+  // handler immediately.
+  bad_message_callback.Run("this message is bad and should feel bad");
+  EXPECT_TRUE(error);
+}
+
+TEST_F(ReportBadMessageTest, ResponseSync) {
+  bool error = false;
+  SetErrorHandler(base::Bind([] (bool* flag) { *flag = true; }, &error));
+
+  SyncMessageResponseContext context;
+  proxy()->RequestResponseSync();
+
+  EXPECT_FALSE(error);
+  context.ReportBadMessage("i don't like this response");
+  EXPECT_TRUE(error);
+}
+
+TEST_F(ReportBadMessageTest, ResponseSyncDeferred) {
+  bool error = false;
+  SetErrorHandler(base::Bind([] (bool* flag) { *flag = true; }, &error));
+
+  ReportBadMessageCallback bad_message_callback;
+  {
+    SyncMessageResponseContext context;
+    proxy()->RequestResponseSync();
+    bad_message_callback = context.GetBadMessageCallback();
+  }
+
+  EXPECT_FALSE(error);
+  bad_message_callback.Run("nope nope nope");
+  EXPECT_TRUE(error);
+}
+
+}  // namespace
+}  // namespace test
+}  // namespace mojo