diff --git a/lib/bandit/websocket/handshake.ex b/lib/bandit/websocket/handshake.ex
index ac6794a5..a736162a 100644
--- a/lib/bandit/websocket/handshake.ex
+++ b/lib/bandit/websocket/handshake.ex
@@ -75,7 +75,8 @@ defmodule Bandit.WebSocket.Handshake do
         {:connection, "Upgrade"},
         {:"sec-websocket-accept", server_key}
       ] ++
-        websocket_extension_header(extensions)
+        websocket_extension_header(extensions) ++
+        conn.resp_headers
 
     inform(conn, 101, headers)
   end
diff --git a/test/bandit/websocket/protocol_test.exs b/test/bandit/websocket/protocol_test.exs
index 774a3e75..939e2b47 100644
--- a/test/bandit/websocket/protocol_test.exs
+++ b/test/bandit/websocket/protocol_test.exs
@@ -153,6 +153,33 @@ defmodule WebSocketProtocolTest do
   end
 
   describe "compressed frames" do
+    test "negotiates compression if globally configured to", context do
+      client = SimpleWebSocketClient.tcp_client(context)
+
+      assert {:ok,
+              [
+                "sec-websocket-extensions: permessage-deflate",
+                "cache-control: max-age=0, private, must-revalidate"
+              ]} =
+               SimpleWebSocketClient.http1_handshake(client, EchoWebSock, [], true)
+
+      deflated_payload = <<74, 76, 28, 5, 163, 96, 20, 12, 119, 0, 0>>
+      SimpleWebSocketClient.send_text_frame(client, deflated_payload, 0xC)
+
+      assert SimpleWebSocketClient.recv_deflated_text_frame(client) == {:ok, deflated_payload}
+    end
+
+    test "does not negotiate compression if not globally configured to", context do
+      context = http_server(context, websocket_options: [compress: false])
+      client = SimpleWebSocketClient.tcp_client(context)
+
+      assert {:ok, ["cache-control: max-age=0, private, must-revalidate"]} =
+               SimpleWebSocketClient.http1_handshake(client, EchoWebSock, [], true)
+
+      SimpleWebSocketClient.send_text_frame(client, "OK")
+      assert SimpleWebSocketClient.recv_text_frame(client) == {:ok, "OK"}
+    end
+
     test "correctly decompresses text frames and sends compressed frames back", context do
       client = SimpleWebSocketClient.tcp_client(context)
       SimpleWebSocketClient.http1_handshake(client, EchoWebSock, [], true)
@@ -212,15 +239,6 @@ defmodule WebSocketProtocolTest do
       assert SimpleWebSocketClient.recv_pong_frame(client) == {:ok, "OK"}
       assert SimpleWebSocketClient.recv_ping_frame(client) == {:ok, "OK"}
     end
-
-    test "does not negotiate compression if not globally configured to", context do
-      context = http_server(context, websocket_options: [compress: false])
-      client = SimpleWebSocketClient.tcp_client(context)
-      assert {:ok, false} = SimpleWebSocketClient.http1_handshake(client, EchoWebSock, [], true)
-
-      SimpleWebSocketClient.send_text_frame(client, "OK")
-      assert SimpleWebSocketClient.recv_text_frame(client) == {:ok, "OK"}
-    end
   end
 
   describe "ping frames" do
diff --git a/test/bandit/websocket/upgrade_test.exs b/test/bandit/websocket/upgrade_test.exs
index b65f715b..898aa1c1 100644
--- a/test/bandit/websocket/upgrade_test.exs
+++ b/test/bandit/websocket/upgrade_test.exs
@@ -16,10 +16,17 @@ defmodule WebSocketUpgradeTest do
         timeout -> [timeout: String.to_integer(timeout)]
       end
 
-    Plug.Conn.upgrade_adapter(conn, :websocket, {websock, :upgrade, connection_opts})
+    conn
+    |> put_resp_header("x-plug-set-header", "itsaheader")
+    |> Plug.Conn.upgrade_adapter(:websocket, {websock, :upgrade, connection_opts})
   end
 
   defmodule UpgradeWebSock do
+    use NoopWebSock
+    def init(opts), do: {:ok, opts}
+  end
+
+  defmodule UpgradeSendOnTerminateWebSock do
     use NoopWebSock
     def init(opts), do: {:ok, [opts, :init]}
     def handle_in(_data, state), do: {:push, {:text, inspect(state)}, state}
@@ -36,7 +43,7 @@ defmodule WebSocketUpgradeTest do
   describe "upgrade support" do
     test "upgrades to a {websock, websock_opts, conn_opts} tuple, respecting options", context do
       client = SimpleWebSocketClient.tcp_client(context)
-      SimpleWebSocketClient.http1_handshake(client, UpgradeWebSock, timeout: "250")
+      SimpleWebSocketClient.http1_handshake(client, UpgradeSendOnTerminateWebSock, timeout: "250")
 
       SimpleWebSocketClient.send_text_frame(client, "")
       {:ok, result} = SimpleWebSocketClient.recv_text_frame(client)
@@ -49,19 +56,14 @@ defmodule WebSocketUpgradeTest do
       assert_in_delta now, then + 250, 50
     end
 
-    test "upgrade responses do not include content-encoding headers", context do
+    test "upgrade responses include headers set from the plug", context do
       client = SimpleWebSocketClient.tcp_client(context)
-      SimpleWebSocketClient.http1_handshake(client, UpgradeWebSock, timeout: "250")
-
-      SimpleWebSocketClient.send_text_frame(client, "")
-      {:ok, result} = SimpleWebSocketClient.recv_text_frame(client)
-      assert result == inspect([:upgrade, :init])
 
-      # Ensure that the passed timeout was recognized
-      then = System.monotonic_time(:millisecond)
-      assert_receive :timeout, 500
-      now = System.monotonic_time(:millisecond)
-      assert_in_delta now, then + 250, 50
+      assert {:ok,
+              [
+                "cache-control: max-age=0, private, must-revalidate",
+                "x-plug-set-header: itsaheader"
+              ]} = SimpleWebSocketClient.http1_handshake(client, UpgradeWebSock)
     end
 
     defmodule MyNoopWebSock do
diff --git a/test/support/simple_websocket_client.ex b/test/support/simple_websocket_client.ex
index 8b01a0a5..fb443772 100644
--- a/test/support/simple_websocket_client.ex
+++ b/test/support/simple_websocket_client.ex
@@ -23,25 +23,32 @@ defmodule SimpleWebSocketClient do
       ] ++ extension_header
     )
 
-    # Because we don't want to consume any more than our headers, we can't use SimpleHTTP1Client
-    {:ok, response} = Transport.recv(client, 164)
-
-    [
-      "HTTP/1.1 101 Switching Protocols",
-      "date: " <> _date,
-      "upgrade: websocket",
-      "connection: Upgrade",
-      "sec-websocket-accept: s3pPLMBiTxaQ9kYGzzhZRbK\+xOo=",
-      ""
-    ] = String.split(response, "\r\n")
-
-    case Transport.recv(client, 2) do
-      {:ok, "\r\n"} ->
-        {:ok, false}
-
-      {:ok, "se"} when deflate ->
-        {:ok, "c-websocket-extensions: permessage-deflate\r\n\r\n"} = Transport.recv(client, 46)
-        {:ok, true}
+    headers = read_headers(client, [])
+
+    ["HTTP/1.1 101 Switching Protocols" | headers] = headers
+    ["date: " <> _date | headers] = headers
+    ["upgrade: websocket" | headers] = headers
+    ["connection: Upgrade" | headers] = headers
+    ["sec-websocket-accept: s3pPLMBiTxaQ9kYGzzhZRbK\+xOo=" | headers] = headers
+    {:ok, headers}
+  end
+
+  # Read one line at a time so as to not consume any body
+  defp read_headers(socket, headers) do
+    case read_line(socket, <<>>) do
+      "" -> headers
+      header -> read_headers(socket, headers ++ [header])
+    end
+  end
+
+  defp read_line(socket, buffer) do
+    case Transport.recv(socket, 1) do
+      {:ok, "\r"} ->
+        {:ok, "\n"} = Transport.recv(socket, 1)
+        buffer
+
+      {:ok, byte} ->
+        read_line(socket, buffer <> byte)
     end
   end