Add support for a binary serializer

lib/slipstream/connection/impl.ex

@@ -77,7 +77,13 @@ defmodule Slipstream.Connection.Impl do
   end
 
   def push_message(message, state) do
-    push_message({:text, encode(message, state)}, state)
+    message =
+      case encode(message, state) do
+        {:binary, message} -> {:binary, message}
+        message when is_binary(message) -> {:text, message}
+      end
+
+    push_message(message, state)
   end
 
   # coveralls-ignore-start

lib/slipstream/serializer.ex

@@ -5,8 +5,13 @@ defmodule Slipstream.Serializer do
 
   @doc """
   Encodes `Slipstream.Message` structs to binary.
+
+  Should return either a binary (string) when using a text based protocol
+  or `{:binary, binary}` for cases where a binary protocol is used over
+  the wire (such as MessagePack).
   """
-  @callback encode!(Slipstream.Message.t(), options :: Keyword.t()) :: binary()
+  @callback encode!(Slipstream.Message.t(), options :: Keyword.t()) ::
+              binary() | {:binary, binary()}
 
   @doc """
   Decodes binary into `Slipstream.Message` struct.

test/fixtures/good_example.ex

@@ -5,16 +5,17 @@ defmodule Slipstream.GoodExample do
 
   use Slipstream, restart: :transient
 
-  @config Application.compile_env!(:slipstream, __MODULE__)
-
   def start_link(opts) do
     Slipstream.start_link(__MODULE__, opts)
   end
 
   @impl Slipstream
-  def init(test_proc) do
+  def init(opts) do
+    {test_proc, opts} = Keyword.pop!(opts, :pid)
+    opts = Keyword.put_new(opts, :uri, "ws://localhost:4001/socket/websocket")
+
     socket =
-      @config
+      opts
       |> connect!()
       |> assign(:test_proc, test_proc)
 

test/slipstream/client_telemetry_test.exs

@@ -45,7 +45,7 @@ defmodule Slipstream.ClientTelemetryTest do
     end
 
     test "when we connect and disconnect, we get expected telemetry" do
-      start_supervised!({@client, self()})
+      start_supervised!({@client, pid: self()})
       assert_receive {@client, :connected}
 
       assert_receive {:telemetry, [:slipstream, :client, :connect, :start],
@@ -66,7 +66,7 @@ defmodule Slipstream.ClientTelemetryTest do
 
     test "when we join a channel, we get expected telemetry" do
       topic = "test:good"
-      pid = start_supervised!({@client, self()})
+      pid = start_supervised!({@client, pid: self()})
       assert_receive {@client, :connected}
       join(pid, topic)
       assert_receive {@client, :joined, ^topic, %{}}
@@ -88,7 +88,7 @@ defmodule Slipstream.ClientTelemetryTest do
 
     test "when we receive a message, we get expected telemetry" do
       topic = "test:good"
-      pid = start_supervised!({@client, self()})
+      pid = start_supervised!({@client, pid: self()})
       assert_receive {@client, :connected}
       join(pid, topic)
       assert_receive {@client, :joined, ^topic, %{}}

test/slipstream/connection_telemetry_test.exs

@@ -45,7 +45,7 @@ defmodule Slipstream.ConnectionTelemetryTest do
     end
 
     test "when we connect and disconnect, we get expected telemetry" do
-      start_supervised!({@client, self()})
+      start_supervised!({@client, [pid: self()]})
       assert_receive {@client, :connected}
 
       assert_receive {:telemetry, [:slipstream, :connection, :connect, :start],
@@ -68,7 +68,7 @@ defmodule Slipstream.ConnectionTelemetryTest do
     end
 
     test "when we successfully connect, we handle mint messages" do
-      start_supervised!({@client, self()})
+      start_supervised!({@client, pid: self()})
       assert_receive {@client, :connected}
 
       assert_receive {:telemetry, [:slipstream, :connection, :connect, :start],