diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 20e1cc1..749fa8f 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -25,10 +25,16 @@ add_executable(UnitTests
     MyClassTests.cpp
     SpdlogTest.cpp
     EnetTest.cpp
+    ServiceHostTest.cpp
+    ${PROJECT_SOURCE_DIR}/apps/client/src/ConnectionToServer.cpp
     EE_boot_stubs.cpp
     ${PROJECT_SOURCE_DIR}/libs/game/src/stdafx.cpp
 )
 
+target_include_directories(UnitTests PRIVATE
+    ${PROJECT_SOURCE_DIR}/apps/client/src
+)
+
 target_compile_definitions(UnitTests PRIVATE FMT_USE_FCNTL=0 SPDLOG_FORCE_COLOR=1)
 
 # Suppress spdlog warnings triggered by -ffast-math when using clang
diff --git a/tests/ServiceHostTest.cpp b/tests/ServiceHostTest.cpp
new file mode 100644
index 0000000..18339b7
--- /dev/null
+++ b/tests/ServiceHostTest.cpp
@@ -0,0 +1,109 @@
+// clang-format off
+#include "gtest/gtest.h"
+#include <unordered_map>
+#include <cfloat>
+#include "enet.h"
+#if defined(__linux__)
+#pragma push_macro("LOCK_READ")
+#pragma push_macro("LOCK_WRITE")
+#undef LOCK_READ
+#undef LOCK_WRITE
+#endif
+#include "stdafx.h"
+#include "@@headers.h"
+#if defined(__linux__)
+#pragma pop_macro("LOCK_WRITE")
+#pragma pop_macro("LOCK_READ")
+#endif
+// clang-format on
+
+extern ENetHost *gClient;
+extern ENetPeer *gClientPeer;
+extern bool gEnetReady;
+extern int gMyId;
+extern std::unordered_map<int, Vec2> gOtherDots;
+
+struct DotPacket {
+  int id;
+  Flt x;
+  Flt y;
+};
+
+void ServiceHost(ENetHost *host);
+
+TEST(ServiceHost, UpdatesDotMap) {
+  ASSERT_EQ(enet_initialize(), 0);
+
+  ENetAddress addr{};
+  addr.host = ENET_HOST_ANY;
+  addr.port = 0; // let OS choose
+  ENetHost *server = enet_host_create(&addr, 1, 1, 0, 0);
+  ASSERT_NE(server, nullptr);
+
+  gClient = enet_host_create(nullptr, 1, 1, 0, 0);
+  ASSERT_NE(gClient, nullptr);
+
+  ENetAddress connectAddr = addr;
+  enet_address_set_host(&connectAddr, "127.0.0.1");
+  connectAddr.port = server->address.port;
+
+  gClientPeer = enet_host_connect(gClient, &connectAddr, 1, 0);
+  ASSERT_NE(gClientPeer, nullptr);
+
+  ENetEvent event;
+  gEnetReady = false;
+  gMyId = -1;
+  gOtherDots.clear();
+
+  for (int i = 0; i < 100 && !gEnetReady; i++) {
+    ServiceHost(gClient);
+    while (enet_host_service(server, &event, 0) > 0) {
+    }
+  }
+  ASSERT_TRUE(gEnetReady);
+
+  DotPacket pkt{42, 1.0f, 2.0f};
+  ENetPacket *p =
+      enet_packet_create(&pkt, sizeof(pkt), ENET_PACKET_FLAG_RELIABLE);
+  enet_host_broadcast(server, 0, p);
+  enet_host_flush(server);
+
+  bool received = false;
+  for (int i = 0; i < 100 && !received; i++) {
+    ServiceHost(gClient);
+    while (enet_host_service(server, &event, 0) > 0) {
+    }
+    if (gOtherDots.find(42) != gOtherDots.end())
+      received = true;
+  }
+  ASSERT_TRUE(received);
+  auto it = gOtherDots.find(42);
+  ASSERT_NE(it, gOtherDots.end());
+  EXPECT_FLOAT_EQ(it->second.x, 1.0f);
+  EXPECT_FLOAT_EQ(it->second.y, 2.0f);
+  EXPECT_EQ(gMyId, 42);
+
+  DotPacket rem{42, FLT_MAX, FLT_MAX};
+  ENetPacket *p2 =
+      enet_packet_create(&rem, sizeof(rem), ENET_PACKET_FLAG_RELIABLE);
+  enet_host_broadcast(server, 0, p2);
+  enet_host_flush(server);
+
+  for (int i = 0; i < 100 && gOtherDots.find(42) != gOtherDots.end(); i++) {
+    ServiceHost(gClient);
+    while (enet_host_service(server, &event, 0) > 0) {
+    }
+  }
+  EXPECT_EQ(gOtherDots.count(42), 0u);
+
+  enet_peer_disconnect(gClientPeer, 0);
+  for (int i = 0; i < 10; i++) {
+    ServiceHost(gClient);
+    while (enet_host_service(server, &event, 0) > 0) {
+    }
+  }
+
+  enet_host_destroy(gClient);
+  enet_host_destroy(server);
+  enet_deinitialize();
+}