diff --git a/foxglove_bridge_base/include/foxglove_bridge/test/test_client.hpp b/foxglove_bridge_base/include/foxglove_bridge/test/test_client.hpp
index 586328d..62742de 100644
--- a/foxglove_bridge_base/include/foxglove_bridge/test/test_client.hpp
+++ b/foxglove_bridge_base/include/foxglove_bridge/test/test_client.hpp
@@ -11,8 +11,8 @@
 
 namespace foxglove {
 
-std::vector<uint8_t> connectClientAndReceiveMsg(const std::string& uri,
-                                                const std::string& topic_name);
+std::future<std::vector<uint8_t>> waitForChannelMsg(ClientInterface* client,
+                                                    SubscriptionId subscriptionId);
 
 std::future<std::vector<Parameter>> waitForParameters(std::shared_ptr<ClientInterface> client,
                                                       const std::string& requestId = std::string());
diff --git a/foxglove_bridge_base/include/foxglove_bridge/websocket_server.hpp b/foxglove_bridge_base/include/foxglove_bridge/websocket_server.hpp
index d18d55a..5f6ee6e 100644
--- a/foxglove_bridge_base/include/foxglove_bridge/websocket_server.hpp
+++ b/foxglove_bridge_base/include/foxglove_bridge/websocket_server.hpp
@@ -1244,7 +1244,7 @@ void Server<ServerConfiguration>::handleUnsubscribe(const nlohmann::json& payloa
     ChannelId chanId = sub->first;
     _handlers.unsubscribeHandler(chanId, hdl);
     std::unique_lock<std::shared_mutex> clientsLock(_clientsMutex);
-    _clients.at(hdl).subscriptionsByChannel.erase(sub);
+    _clients.at(hdl).subscriptionsByChannel.erase(chanId);
   }
 }
 
diff --git a/foxglove_bridge_base/src/test/test_client.cpp b/foxglove_bridge_base/src/test/test_client.cpp
index 25457e8..5e5f612 100644
--- a/foxglove_bridge_base/src/test/test_client.cpp
+++ b/foxglove_bridge_base/src/test/test_client.cpp
@@ -8,46 +8,24 @@
 
 namespace foxglove {
 
-constexpr auto DEFAULT_TIMEOUT = std::chrono::seconds(5);
-
-std::vector<uint8_t> connectClientAndReceiveMsg(const std::string& uri,
-                                                const std::string& topicName) {
-  // Set up text message handler to resolve the promise when the topic is advertised
-  auto wsClient = std::make_shared<foxglove::Client<websocketpp::config::asio_client>>();
-  std::promise<nlohmann::json> channelPromise;
-  auto channelFuture = waitForChannel(wsClient, topicName);
-
-  // Connect the client and wait for the channel future
-  if (std::future_status::ready != wsClient->connect(uri).wait_for(DEFAULT_TIMEOUT)) {
-    throw std::runtime_error("Client failed to connect");
-  } else if (std::future_status::ready != channelFuture.wait_for(DEFAULT_TIMEOUT)) {
-    throw std::runtime_error("Client failed to receive channel");
-  }
+std::future<std::vector<uint8_t>> waitForChannelMsg(ClientInterface* client,
+                                                    SubscriptionId subscriptionId) {
+  // Set up binary message handler to resolve when a binary message has been received
+  auto promise = std::make_shared<std::promise<std::vector<uint8_t>>>();
+  auto future = promise->get_future();
 
-  const auto channel = channelFuture.get();
-  const SubscriptionId subscriptionId = 1;
+  client->setBinaryMessageHandler(
+    [promise = std::move(promise), subscriptionId](const uint8_t* data, size_t dataLength) {
+      if (ReadUint32LE(data + 1) != subscriptionId) {
+        return;
+      }
+      const size_t offset = 1 + 4 + 8;
+      std::vector<uint8_t> dataCopy(dataLength - offset);
+      std::memcpy(dataCopy.data(), data + offset, dataLength - offset);
+      promise->set_value(std::move(dataCopy));
+    });
 
-  // Set up binary message handler to resolve when a binary message has been received
-  std::promise<std::vector<uint8_t>> msgPromise;
-  auto msgFuture = msgPromise.get_future();
-  wsClient->setBinaryMessageHandler([&msgPromise](const uint8_t* data, size_t dataLength) {
-    if (ReadUint32LE(data + 1) != subscriptionId) {
-      return;
-    }
-    const size_t offset = 1 + 4 + 8;
-    std::vector<uint8_t> dataCopy(dataLength - offset);
-    std::memcpy(dataCopy.data(), data + offset, dataLength - offset);
-    msgPromise.set_value(std::move(dataCopy));
-  });
-
-  // Subscribe to the channel that corresponds to the topic
-  wsClient->subscribe({{subscriptionId, channel.id}});
-
-  // Wait until we have received a binary message
-  if (std::future_status::ready != msgFuture.wait_for(DEFAULT_TIMEOUT)) {
-    throw std::runtime_error("Client failed to receive message");
-  }
-  return msgFuture.get();
+  return future;
 }
 
 std::future<std::vector<Parameter>> waitForParameters(std::shared_ptr<ClientInterface> client,
diff --git a/ros1_foxglove_bridge/tests/smoke_test.cpp b/ros1_foxglove_bridge/tests/smoke_test.cpp
index 60aada0..72afd91 100644
--- a/ros1_foxglove_bridge/tests/smoke_test.cpp
+++ b/ros1_foxglove_bridge/tests/smoke_test.cpp
@@ -80,10 +80,24 @@ TEST(SmokeTest, testSubscription) {
   // Connect a few clients and make sure that they receive the correct message
   const auto clientCount = 3;
   for (auto i = 0; i < clientCount; ++i) {
-    std::vector<uint8_t> msgData;
-    ASSERT_NO_THROW(msgData = foxglove::connectClientAndReceiveMsg(URI, topic_name));
+    // Set up a client and subscribe to the channel.
+    auto client = std::make_shared<foxglove::Client<websocketpp::config::asio_client>>();
+    auto channelFuture = foxglove::waitForChannel(client, topic_name);
+    ASSERT_EQ(std::future_status::ready, client->connect(URI).wait_for(ONE_SECOND));
+    ASSERT_EQ(std::future_status::ready, channelFuture.wait_for(ONE_SECOND));
+    const foxglove::Channel channel = channelFuture.get();
+    const foxglove::SubscriptionId subscriptionId = 1;
+
+    // Subscribe to the channel and confirm that the promise resolves
+    auto msgFuture = waitForChannelMsg(client.get(), subscriptionId);
+    client->subscribe({{subscriptionId, channel.id}});
+    ASSERT_EQ(std::future_status::ready, msgFuture.wait_for(ONE_SECOND));
+    const auto msgData = msgFuture.get();
     ASSERT_EQ(sizeof(HELLO_WORLD_BINARY), msgData.size());
     EXPECT_EQ(0, std::memcmp(HELLO_WORLD_BINARY, msgData.data(), msgData.size()));
+
+    // Unsubscribe from the channel again.
+    client->unsubscribe({subscriptionId});
   }
 }
 
@@ -95,11 +109,24 @@ TEST(SmokeTest, testSubscriptionParallel) {
   pub.publish(std::string("hello world"));
 
   // Connect a few clients (in parallel) and make sure that they receive the correct message
+  const foxglove::SubscriptionId subscriptionId = 1;
+  auto clients = {
+    std::make_shared<foxglove::Client<websocketpp::config::asio_client>>(),
+    std::make_shared<foxglove::Client<websocketpp::config::asio_client>>(),
+    std::make_shared<foxglove::Client<websocketpp::config::asio_client>>(),
+  };
+
   std::vector<std::future<std::vector<uint8_t>>> futures;
-  const auto clientCount = 3;
-  for (auto i = 0; i < clientCount; ++i) {
-    futures.push_back(
-      std::async(std::launch::async, foxglove::connectClientAndReceiveMsg, URI, topic_name));
+  for (auto client : clients) {
+    futures.push_back(waitForChannelMsg(client.get(), subscriptionId));
+  }
+
+  for (auto client : clients) {
+    auto channelFuture = foxglove::waitForChannel(client, topic_name);
+    ASSERT_EQ(std::future_status::ready, client->connect(URI).wait_for(ONE_SECOND));
+    ASSERT_EQ(std::future_status::ready, channelFuture.wait_for(ONE_SECOND));
+    const foxglove::Channel channel = channelFuture.get();
+    client->subscribe({{subscriptionId, channel.id}});
   }
 
   for (auto& future : futures) {
@@ -108,6 +135,10 @@ TEST(SmokeTest, testSubscriptionParallel) {
     ASSERT_EQ(sizeof(HELLO_WORLD_BINARY), msgData.size());
     EXPECT_EQ(0, std::memcmp(HELLO_WORLD_BINARY, msgData.data(), msgData.size()));
   }
+
+  for (auto client : clients) {
+    client->unsubscribe({subscriptionId});
+  }
 }
 
 TEST(SmokeTest, testPublishing) {
diff --git a/ros2_foxglove_bridge/tests/smoke_test.cpp b/ros2_foxglove_bridge/tests/smoke_test.cpp
index d9699e1..17f639e 100644
--- a/ros2_foxglove_bridge/tests/smoke_test.cpp
+++ b/ros2_foxglove_bridge/tests/smoke_test.cpp
@@ -173,10 +173,24 @@ TEST(SmokeTest, testSubscription) {
   // Connect a few clients and make sure that they receive the correct message
   const auto clientCount = 3;
   for (auto i = 0; i < clientCount; ++i) {
-    std::vector<uint8_t> msgData;
-    ASSERT_NO_THROW(msgData = foxglove::connectClientAndReceiveMsg(URI, topic_name));
+    // Set up a client and subscribe to the channel.
+    auto client = std::make_shared<foxglove::Client<websocketpp::config::asio_client>>();
+    auto channelFuture = foxglove::waitForChannel(client, topic_name);
+    ASSERT_EQ(std::future_status::ready, client->connect(URI).wait_for(ONE_SECOND));
+    ASSERT_EQ(std::future_status::ready, channelFuture.wait_for(ONE_SECOND));
+    const foxglove::Channel channel = channelFuture.get();
+    const foxglove::SubscriptionId subscriptionId = 1;
+
+    // Subscribe to the channel and confirm that the promise resolves
+    auto msgFuture = waitForChannelMsg(client.get(), subscriptionId);
+    client->subscribe({{subscriptionId, channel.id}});
+    ASSERT_EQ(std::future_status::ready, msgFuture.wait_for(ONE_SECOND));
+    const auto msgData = msgFuture.get();
     ASSERT_EQ(sizeof(HELLO_WORLD_BINARY), msgData.size());
     EXPECT_EQ(0, std::memcmp(HELLO_WORLD_BINARY, msgData.data(), msgData.size()));
+
+    // Unsubscribe from the channel again.
+    client->unsubscribe({subscriptionId});
   }
 }
 
@@ -193,11 +207,24 @@ TEST(SmokeTest, testSubscriptionParallel) {
   pub->publish(rosMsg);
 
   // Connect a few clients (in parallel) and make sure that they receive the correct message
+  const foxglove::SubscriptionId subscriptionId = 1;
+  auto clients = {
+    std::make_shared<foxglove::Client<websocketpp::config::asio_client>>(),
+    std::make_shared<foxglove::Client<websocketpp::config::asio_client>>(),
+    std::make_shared<foxglove::Client<websocketpp::config::asio_client>>(),
+  };
+
   std::vector<std::future<std::vector<uint8_t>>> futures;
-  const auto clientCount = 3;
-  for (auto i = 0; i < clientCount; ++i) {
-    futures.push_back(
-      std::async(std::launch::async, foxglove::connectClientAndReceiveMsg, URI, topic_name));
+  for (auto client : clients) {
+    futures.push_back(waitForChannelMsg(client.get(), subscriptionId));
+  }
+
+  for (auto client : clients) {
+    auto channelFuture = foxglove::waitForChannel(client, topic_name);
+    ASSERT_EQ(std::future_status::ready, client->connect(URI).wait_for(ONE_SECOND));
+    ASSERT_EQ(std::future_status::ready, channelFuture.wait_for(ONE_SECOND));
+    const foxglove::Channel channel = channelFuture.get();
+    client->subscribe({{subscriptionId, channel.id}});
   }
 
   for (auto& future : futures) {
@@ -206,6 +233,10 @@ TEST(SmokeTest, testSubscriptionParallel) {
     ASSERT_EQ(sizeof(HELLO_WORLD_BINARY), msgData.size());
     EXPECT_EQ(0, std::memcmp(HELLO_WORLD_BINARY, msgData.data(), msgData.size()));
   }
+
+  for (auto client : clients) {
+    client->unsubscribe({subscriptionId});
+  }
 }
 
 TEST(SmokeTest, testPublishing) {