[cast_bindings] Tests for MessagePort abstraction.

Test coverage for public MessagePort interface and its interactions with
MessagePort::Receiver. Includes conversion to and from the underlying
platform type of MessagePortCast or MessagePortFuchsia.

Bug: 1135377
Test: //components/cast/message_port:message_port_test added
Change-Id: I5e51aa5e08eb1e3e8957963b033497a94fe0bdac
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2515208
Commit-Queue: Shawn Quereshi <shawnq@google.com>
Reviewed-by: Kevin Marshall <kmarshall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#824126}

components/BUILD.gn

@@ -233,6 +233,7 @@ test("components_unittests") {
       "//components/blocked_content:unit_tests",
       "//components/browsing_data/content:unit_tests",
       "//components/captive_portal/content:unit_tests",
+      "//components/cast:unit_tests",
       "//components/cast_certificate:unit_tests",
       "//components/cast_channel:unit_tests",
       "//components/certificate_transparency:unit_tests",

components/cast/BUILD.gn

@@ -5,3 +5,8 @@
 source_set("export") {
   sources = [ "cast_component_export.h" ]
 }
+
+source_set("unit_tests") {
+  testonly = true
+  deps = [ "//components/cast/message_port:message_port_unittest" ]
+}

components/cast/message_port/BUILD.gn

@@ -3,6 +3,7 @@
 # found in the LICENSE file.
 
 import("//build/config/features.gni")
+import("//testing/test.gni")
 
 source_set("message_port") {
   if (is_fuchsia) {
@@ -58,6 +59,21 @@ source_set("message_port_cast") {
   ]
 }
 
+source_set("message_port_unittest") {
+  testonly = true
+  deps = [
+    ":message_port",
+    ":test_message_port_receiver",
+    "//base/test:test_support",
+    "//mojo/core/embedder",
+    "//testing/gtest",
+  ]
+
+  if (is_fuchsia || is_chromecast) {
+    sources = [ "message_port_unittest.cc" ]
+  }
+}
+
 source_set("test_message_port_receiver") {
   testonly = true
   sources = [
@@ -65,7 +81,7 @@ source_set("test_message_port_receiver") {
     "test_message_port_receiver.h",
   ]
   deps = [
-    ":message_port",
+    ":public",
     "//base",
   ]
 }

components/cast/message_port/DEPS

 include_rules = [
-  "+third_party/blink/public/common/messaging",
   "+fuchsia",
+  "+third_party/blink/public/common/messaging",
 ]

components/cast/message_port/message_port_cast.cc

@@ -63,7 +63,6 @@ blink::WebMessagePort MessagePortCast::TakePort() {
   return std::move(port_);
 }
 
-// cast_api_bindings::MessagePortCast implementation
 bool MessagePortCast::PostMessage(base::StringPiece message) {
   return PostMessageWithTransferables(message, {});
 }

components/cast/message_port/message_port_unittest.cc

+// Copyright 2020 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 "components/cast/message_port/message_port.h"
+#include "base/run_loop.h"
+#include "base/test/task_environment.h"
+#include "build/build_config.h"
+#include "components/cast/message_port/test_message_port_receiver.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+#if defined(OS_FUCHSIA)
+#include "components/cast/message_port/message_port_fuchsia.h"
+#include "fuchsia/fidl/chromium/cast/cpp/fidl.h"
+#else
+#include "components/cast/message_port/message_port_cast.h"  // nogncheck
+#include "third_party/blink/public/common/messaging/web_message_port.h"  // nogncheck
+#endif  // defined(OS_FUCHSIA)
+
+#ifdef PostMessage
+#undef PostMessage
+#endif
+
+namespace cast_api_bindings {
+
+class MessagePortTest : public ::testing::Test {
+ public:
+  MessagePortTest()
+      : task_environment_(base::test::TaskEnvironment::MainThreadType::IO) {
+    MessagePort::CreatePair(&client_, &server_);
+  }
+
+  ~MessagePortTest() override = default;
+
+  void SetDefaultReceivers() {
+    client_->SetReceiver(&client_receiver_);
+    server_->SetReceiver(&server_receiver_);
+  }
+
+  // Posts multiple |messages| from |sender| to |receiver| and validates their
+  // arrival order
+  void PostMessages(const std::vector<std::string>& messages,
+                    MessagePort* sender,
+                    TestMessagePortReceiver* receiver) {
+    for (const auto& message : messages) {
+      sender->PostMessage(message);
+    }
+
+    EXPECT_TRUE(receiver->RunUntilMessageCountEqual(messages.size()));
+    for (size_t i = 0; i < messages.size(); i++) {
+      EXPECT_EQ(receiver->buffer()[i].first, messages[i]);
+    }
+  }
+
+  // Posts a |port| from |sender| to |receiver| and validates its arrival.
+  // Returns the transferred |port|.
+  std::unique_ptr<MessagePort> PostMessageWithTransferables(
+      std::unique_ptr<MessagePort> port,
+      MessagePort* sender,
+      TestMessagePortReceiver* receiver) {
+    std::vector<std::unique_ptr<MessagePort>> ports;
+    ports.emplace_back(std::move(port));
+    sender->PostMessageWithTransferables("", std::move(ports));
+    EXPECT_TRUE(receiver->RunUntilMessageCountEqual(1));
+    EXPECT_EQ(receiver->buffer()[0].second.size(), (size_t)1);
+    return std::move(receiver->buffer()[0].second[0]);
+  }
+
+  void TestPostMessage() {
+    SetDefaultReceivers();
+    PostMessages({"from client"}, client_.get(), &server_receiver_);
+    PostMessages({"from server"}, server_.get(), &client_receiver_);
+  }
+
+ protected:
+  std::unique_ptr<MessagePort> client_;
+  std::unique_ptr<MessagePort> server_;
+  TestMessagePortReceiver client_receiver_;
+  TestMessagePortReceiver server_receiver_;
+
+ private:
+  const base::test::TaskEnvironment task_environment_;
+};
+
+TEST_F(MessagePortTest, Close) {
+  SetDefaultReceivers();
+  ASSERT_TRUE(client_->CanPostMessage());
+  ASSERT_TRUE(server_->CanPostMessage());
+
+  server_->Close();
+  client_receiver_.RunUntilDisconnected();
+  ASSERT_FALSE(client_->CanPostMessage());
+  ASSERT_FALSE(server_->CanPostMessage());
+}
+
+TEST_F(MessagePortTest, OnError) {
+  server_receiver_.SetOnMessageResult(false);
+  SetDefaultReceivers();
+  client_->PostMessage("");
+
+#if defined(OS_FUCHSIA)
+  // blink::WebMessagePort reports failure when PostMessage returns false, but
+  // fuchsia::web::MessagePort will not report the error until the port closes
+  server_receiver_.RunUntilMessageCountEqual(1);
+  server_.reset();
+#endif
+
+  client_receiver_.RunUntilDisconnected();
+}
+
+TEST_F(MessagePortTest, PostMessage) {
+  TestPostMessage();
+}
+
+TEST_F(MessagePortTest, PostMessageMultiple) {
+  SetDefaultReceivers();
+  PostMessages({"c1", "c2", "c3"}, client_.get(), &server_receiver_);
+  PostMessages({"s1", "s2", "s3"}, server_.get(), &client_receiver_);
+}
+
+TEST_F(MessagePortTest, PostMessageWithTransferables) {
+  std::unique_ptr<MessagePort> port0;
+  std::unique_ptr<MessagePort> port1;
+  TestMessagePortReceiver port0_receiver;
+  TestMessagePortReceiver port1_receiver;
+  MessagePort::CreatePair(&port0, &port1);
+
+  // If the ports are represented by multiple types as in the case of
+  // MessagePortFuchsia, make sure both are transferrable
+  SetDefaultReceivers();
+  port0 = PostMessageWithTransferables(std::move(port0), client_.get(),
+                                       &server_receiver_);
+  port1 = PostMessageWithTransferables(std::move(port1), server_.get(),
+                                       &client_receiver_);
+
+  // Make sure the ports are still usable
+  port0->SetReceiver(&port0_receiver);
+  port1->SetReceiver(&port1_receiver);
+  PostMessages({"from port0"}, port0.get(), &port1_receiver);
+  PostMessages({"from port1"}, port1.get(), &port0_receiver);
+}
+
+TEST_F(MessagePortTest, WrapPlatformPort) {
+  // Initialize ports from the platform type instead of agnostic CreatePair
+#if defined(OS_FUCHSIA)
+  fidl::InterfaceHandle<fuchsia::web::MessagePort> port0;
+  fidl::InterfaceRequest<fuchsia::web::MessagePort> port1 = port0.NewRequest();
+  client_ = MessagePortFuchsia::Create(std::move(port0));
+  server_ = MessagePortFuchsia::Create(std::move(port1));
+#else
+  auto pair = blink::WebMessagePort::CreatePair();
+  client_ = MessagePortCast::Create(std::move(pair.first));
+  server_ = MessagePortCast::Create(std::move(pair.second));
+#endif  // defined(OS_FUCHSIA)
+
+  TestPostMessage();
+}
+
+TEST_F(MessagePortTest, UnwrapPlatformPortCast) {
+  // Test unwrapping via TakePort (rewrapped for test methods)
+#if defined(OS_FUCHSIA)
+  client_ = MessagePortFuchsia::Create(
+      MessagePortFuchsia::FromMessagePort(client_.get())->TakeClientHandle());
+  server_ = MessagePortFuchsia::Create(
+      MessagePortFuchsia::FromMessagePort(server_.get())->TakeServiceRequest());
+#else
+  client_ = MessagePortCast::Create(
+      MessagePortCast::FromMessagePort(client_.get())->TakePort());
+  server_ = MessagePortCast::Create(
+      MessagePortCast::FromMessagePort(server_.get())->TakePort());
+#endif  // defined(OS_FUCHSIA)
+
+  TestPostMessage();
+}
+
+}  // namespace cast_api_bindings

components/cast/message_port/test_message_port_receiver.cc

@@ -12,6 +12,10 @@ TestMessagePortReceiver::TestMessagePortReceiver() = default;
 
 TestMessagePortReceiver::~TestMessagePortReceiver() = default;
 
+void TestMessagePortReceiver::SetOnMessageResult(bool result) {
+  on_message_result_ = result;
+}
+
 bool TestMessagePortReceiver::RunUntilMessageCountEqual(size_t message_count) {
   base::RunLoop run_loop;
   on_receive_satisfied_ = run_loop.QuitClosure();
@@ -34,7 +38,7 @@ bool TestMessagePortReceiver::OnMessage(
     DCHECK(on_receive_satisfied_);
     std::move(on_receive_satisfied_).Run();
   }
-  return true;
+  return on_message_result_;
 }
 
 void TestMessagePortReceiver::OnPipeError() {

components/cast/message_port/test_message_port_receiver.h

@@ -29,6 +29,9 @@ class TestMessagePortReceiver
   // Spins a RunLoop until the associated MessagePort is disconnected.
   void RunUntilDisconnected();
 
+  // Sets the return value of OnMessage
+  void SetOnMessageResult(bool result);
+
   std::vector<
       std::pair<std::string, std::vector<std::unique_ptr<MessagePort>>>>&
   buffer() {
@@ -46,6 +49,7 @@ class TestMessagePortReceiver
   size_t message_count_target_ = 0;
   base::OnceClosure on_receive_satisfied_;
   base::OnceClosure on_disconnect_;
+  bool on_message_result_ = true;
 };
 
 }  // namespace cast_api_bindings