document the test api

lib/exq/mock.ex

@@ -6,11 +6,17 @@ defmodule Exq.Mock do
   @timeout 30000
 
   defmodule State do
+    @moduledoc false
     defstruct default_mode: :redis, jobs: %{}, modes: %{}
   end
 
   ### Public api
 
+  @doc """
+  Start Mock server
+
+  * `mode` - The default mode that's used for all tests. See `set_mode/1` for details.
+  """
   def start_link(options \\ []) do
     queue_adapter = Config.get(:queue_adapter)
 
@@ -25,10 +31,22 @@ defmodule Exq.Mock do
     GenServer.start_link(__MODULE__, options, name: __MODULE__)
   end
 
+  @doc """
+  Set the mode for current test
+
+  * `:redis` - jobs get enqueued and processed via redis.
+  * `:fake` - jobs get enqueued in a local queue
+  * `:inline` - jobs get executed in the same process
+  """
   def set_mode(mode) when mode in [:redis, :inline, :fake] do
     GenServer.call(__MODULE__, {:mode, self(), mode}, @timeout)
   end
 
+  @doc """
+  List of enqueued jobs
+
+  This only works if the mode is set to `:fake`
+  """
   def jobs do
     GenServer.call(__MODULE__, {:jobs, self()}, @timeout)
   end
@@ -40,6 +58,7 @@ defmodule Exq.Mock do
     {:ok, %State{default_mode: Keyword.get(options, :mode, :redis)}}
   end
 
+  @doc false
   def enqueue(pid, queue, worker, args, options) do
     {:ok, runnable} =
       GenServer.call(
@@ -51,6 +70,7 @@ defmodule Exq.Mock do
     runnable.()
   end
 
+  @doc false
   def enqueue_at(pid, queue, time, worker, args, options) do
     {:ok, runnable} =
       GenServer.call(
@@ -62,6 +82,7 @@ defmodule Exq.Mock do
     runnable.()
   end
 
+  @doc false
   def enqueue_in(pid, queue, offset, worker, args, options) do
     {:ok, runnable} =
       GenServer.call(