Add tests for SUBSCRIBE

Author: farhadi

Dockerfile

@@ -9,7 +9,7 @@ RUN mix local.rebar --force &&\
 
 # Cache dependencies
 COPY mix.exs mix.lock ./
-RUN mix deps.get
+RUN mix deps.get --only prod
 COPY config ./config
 RUN mix deps.compile
 

config/test.exs

@@ -2,5 +2,6 @@ import Config
 
 config :injector, [
   {:mnesia, MnesiaMock},
+  {:pg2, Pg2Mock},
   {Redex.Protocol, ProtocolMock}
 ]

lib/redex/command/subscribe.ex

@@ -1,6 +1,10 @@
 defmodule Redex.Command.SUBSCRIBE do
   use Redex.Command
 
+  import Injector
+
+  inject :pg2, as: Pg2
+
   def exec(channels, state) when channels != [] do
     subscribe(channels, state)
   end
@@ -10,16 +14,16 @@ defmodule Redex.Command.SUBSCRIBE do
   defp subscribe([], state), do: state
 
   defp subscribe([ch | channels], state = %State{channels: subscribed}) do
-    subscribed =
+    state =
       if ch in subscribed do
-        subscribed
+        state
       else
-        :pg2.create(ch)
-        :pg2.join(ch, self())
-        [ch | subscribed]
+        Pg2.create(ch)
+        Pg2.join(ch, self())
+        %{state | channels: [ch | subscribed]}
       end
 
-    reply(["subscribe", ch, length(subscribed)], state)
+    reply(["subscribe", ch, length(state.channels)], state)
     subscribe(channels, state)
   end
 end

mix.exs

@@ -36,11 +36,11 @@ defmodule Redex.MixProject do
   defp deps do
     [
       {:injector, "~> 0.2"},
-      {:mox, "~> 0.5"},
       {:manifold, "~> 1.2"},
       {:ranch, "~> 1.7"},
       {:libcluster, "~> 3.1"},
       {:nimble_parsec, "~> 0.5.0"},
+      {:mox, "~> 0.5", only: :test},
       {:excoveralls, "~> 0.11.1", only: :test},
       {:dialyxir, "~> 1.0.0-rc.6", only: :dev, runtime: false},
       {:stream_data, "~> 0.4", only: [:dev, :test]}

test/redex/command/quit_test.exs

@@ -17,7 +17,7 @@ defmodule Redex.Command.QuitTest do
       TransportMock
       |> expect(:close, fn :socket -> :ok end)
 
-      exec(args, state)
+      assert state == exec(args, state)
     end
   end
 end

test/redex/command/subscribe_test.exs

@@ -0,0 +1,49 @@
+defmodule Redex.Command.SubscribeTest do
+  use ExUnit.Case, async: true
+  use ExUnitProperties
+
+  import Mox
+  import Redex.DataGenerators
+  import Redex.Command.SUBSCRIBE
+
+  setup :verify_on_exit!
+
+  property "SUBSCRIBE to some channels" do
+    check all state <- state(channels: true),
+              channels <- list_of(binary(), min_length: 1) do
+      new_state =
+        for ch <- channels, reduce: state do
+          state = %{channels: channels} ->
+            channels = if ch in channels do
+              channels
+            else
+              Pg2Mock
+              |> expect(:create, fn ^ch -> :ok end)
+              |> expect(:join, fn ^ch, pid when pid == self() -> :ok end)
+
+              [ch | channels]
+            end
+            state = %{state | channels: channels}
+            subscribed = length(channels)
+
+            ProtocolMock
+            |> expect(:reply, fn ["subscribe", ^ch, ^subscribed], ^state -> state end)
+
+            state
+        end
+
+      assert new_state == exec(channels, state)
+    end
+  end
+
+  test "SUBSCRIBE with wrong number of arguments" do
+    error = {:error, "ERR wrong number of arguments for 'SUBSCRIBE' command"}
+
+    state = state()
+
+    ProtocolMock
+    |> expect(:reply, fn ^error, ^state -> state end)
+
+    assert state == exec([], state)
+  end
+end

test/support/data_generators.ex

@@ -48,14 +48,17 @@ defmodule Redex.DataGenerators do
 
   def state(opts \\ []) do
     quorum = if opts[:quorum], do: constant(opts[:quorum]), else: positive_integer()
+    channels = if opts[:channels], do: uniq_list_of(binary(), min_length: 1), else: constant([])
 
     gen all db <- integer(0..100),
-            quorum <- quorum do
+            quorum <- quorum,
+            channels <- channels do
       %State{
         transport: TransportMock,
         socket: :socket,
         db: db,
-        quorum: quorum
+        quorum: quorum,
+        channels: channels
       }
     end
   end

test/support/mocks.ex

@@ -1,3 +1,4 @@
 Mox.defmock(TransportMock, for: Redex.TransportBehaviour)
 Mox.defmock(MnesiaMock, for: Redex.MnesiaBehaviour)
+Mox.defmock(Pg2Mock, for: Redex.Pg2Behaviour)
 Mox.defmock(ProtocolMock, for: Redex.Protocol)

test/support/pg2_behaviour.ex

@@ -0,0 +1,4 @@
+defmodule Redex.Pg2Behaviour do
+  @callback create(any) :: :ok
+  @callback join(any, pid) :: :ok
+end