From 555c3d95fcc53fa98fd15410ac215127472edfe4 Mon Sep 17 00:00:00 2001
From: sfc-gh-tclinkenbeard <trevor.clinkenbeard@snowflake.com>
Date: Wed, 23 Dec 2020 19:54:01 -0400
Subject: [PATCH] Added fdbrpc/SimExternalClient unit test

---
 fdbrpc/SimExternalConnection.actor.cpp  | 68 ++++++++++++++++++++++++-
 fdbserver/workloads/UnitTests.actor.cpp |  2 +
 2 files changed, 68 insertions(+), 2 deletions(-)

diff --git a/fdbrpc/SimExternalConnection.actor.cpp b/fdbrpc/SimExternalConnection.actor.cpp
index e1abab898b..40ceaed586 100644
--- a/fdbrpc/SimExternalConnection.actor.cpp
+++ b/fdbrpc/SimExternalConnection.actor.cpp
@@ -23,7 +23,10 @@
 #include <chrono>
 #include <thread>
 
+#include "fdbclient/FDBTypes.h"
 #include "fdbrpc/SimExternalConnection.h"
+#include "flow/Net2Packet.h"
+#include "flow/UnitTest.h"
 #include "flow/actorcompiler.h" // This must be the last #include.
 
 using namespace boost::asio;
@@ -47,6 +50,9 @@ Future<Void> SimExternalConnection::onWritable() {
 }
 
 Future<Void> SimExternalConnection::onReadable() {
+	if (!readBuffer.empty()) {
+		return Void();
+	}
 	return onReadableTrigger.onTrigger();
 }
 
@@ -126,9 +132,67 @@ Future<Reference<IConnection>> SimExternalConnection::connect(NetworkAddress toA
 	} else {
 		address = boost::asio::ip::address_v4(ip.toV4());
 	}
-	socket.connect(ip::tcp::endpoint(address, toAddr.port));
-	return Reference<IConnection>(new SimExternalConnection(std::move(socket)));
+	boost::system::error_code err;
+	socket.connect(ip::tcp::endpoint(address, toAddr.port), err);
+	if (err) {
+		return Reference<IConnection>();
+	} else {
+		return Reference<IConnection>(new SimExternalConnection(std::move(socket)));
+	}
 }
 
 SimExternalConnection::SimExternalConnection(ip::tcp::socket&& socket)
   : socket(std::move(socket)), dbgid(deterministicRandom()->randomUniqueID()) {}
+
+static constexpr auto testEchoServerPort = 8000;
+
+static void testEchoServer() {
+	io_service ios;
+	ip::tcp::acceptor acceptor(ios, ip::tcp::endpoint(ip::tcp::v4(), testEchoServerPort));
+
+	ip::tcp::socket socket(ios);
+	acceptor.accept(socket);
+	loop {
+		char data[10000];
+		boost::system::error_code err;
+		auto length = socket.read_some(buffer(data), err);
+		if (err == boost::asio::error::eof) {
+			return;
+		}
+		ASSERT(!err);
+		write(socket, buffer(data, length));
+	}
+}
+
+TEST_CASE("fdbrpc/SimExternalClient") {
+	state const size_t maxDataLength = 10000;
+	state std::thread serverThread([] { return testEchoServer(); });
+	state UnsentPacketQueue packetQueue;
+	state Reference<IConnection> externalConn;
+	state const IPAddress localhost = IPAddress::parse("127.0.0.1").get();
+	loop {
+		// Wait until server is ready
+		Reference<IConnection> _externalConn =
+		    wait(INetworkConnections::net()->connectExternal(NetworkAddress(localhost, testEchoServerPort)));
+		if (_externalConn.isValid()) {
+			externalConn = std::move(_externalConn);
+			break;
+		}
+		std::this_thread::sleep_for(std::chrono::seconds(1));
+	}
+	state Key data = deterministicRandom()->randomAlphaNumeric(deterministicRandom()->randomInt(0, maxDataLength + 1));
+	PacketWriter packetWriter(packetQueue.getWriteBuffer(data.size()), nullptr, Unversioned());
+	packetWriter.serializeBytes(data);
+	wait(externalConn->onWritable());
+	externalConn->write(packetQueue.getUnsent());
+	wait(externalConn->onReadable());
+	std::vector<uint8_t> vec(data.size());
+	externalConn->read(&vec[0], &vec[0] + vec.size());
+	externalConn->close();
+	StringRef echo(&vec[0], vec.size());
+	ASSERT(echo.toString() == data.toString());
+	serverThread.join();
+	return Void();
+}
+
+void forceLinkSimExternalConnectionTests() {}
diff --git a/fdbserver/workloads/UnitTests.actor.cpp b/fdbserver/workloads/UnitTests.actor.cpp
index 10fa028354..d81d85636d 100644
--- a/fdbserver/workloads/UnitTests.actor.cpp
+++ b/fdbserver/workloads/UnitTests.actor.cpp
@@ -28,6 +28,7 @@ void forceLinkFlowTests();
 void forceLinkVersionedMapTests();
 void forceLinkMemcpyTests();
 void forceLinkMemcpyPerfTests();
+void forceLinkSimExternalConnectionTests();
 
 struct UnitTestWorkload : TestWorkload {
 	bool enabled;
@@ -49,6 +50,7 @@ struct UnitTestWorkload : TestWorkload {
 		forceLinkVersionedMapTests();
 		forceLinkMemcpyTests();
 		forceLinkMemcpyPerfTests();
+		forceLinkSimExternalConnectionTests();
 	}
 
 	std::string description() const override { return "UnitTests"; }