diff --git a/lib/local_cluster.ex b/lib/local_cluster.ex
index e9a92fa..36b028e 100644
--- a/lib/local_cluster.ex
+++ b/lib/local_cluster.ex
@@ -17,19 +17,21 @@ defmodule LocalCluster do
     start_boot_server = fn ->
       # voodoo flag to generate a "started" atom flag
       :global_flags.once("local_cluster:started", fn ->
-        { :ok, _ } = :erl_boot_server.start([
-          { 127, 0, 0, 1 }
-        ])
+        {:ok, _} =
+          :erl_boot_server.start([
+            {127, 0, 0, 1}
+          ])
       end)
+
       :ok
     end
 
     # only ever handle the :erl_boot_server on the initial startup
-    case :net_kernel.start([ :"manager@127.0.0.1" ]) do
+    case :net_kernel.start([:"manager@127.0.0.1"]) do
       # handle nodes that have already been started elsewhere
-      { :error, { :already_started, _ } } -> start_boot_server.()
+      {:error, {:already_started, _}} -> start_boot_server.()
       # handle the node being started
-      { :ok, _ } -> start_boot_server.()
+      {:ok, _} -> start_boot_server.()
       # pass anything else
       anything -> anything
     end
@@ -43,39 +45,51 @@ defmodule LocalCluster do
   nodes are linked to the current process, and so will terminate when the
   parent process does for automatic cleanup.
   """
-  @spec start_nodes(binary, integer, Keyword.t) :: [ atom ]
+  @spec start_nodes(binary, integer, Keyword.t()) :: [atom]
   def start_nodes(prefix, amount, options \\ [])
-  when (is_binary(prefix) or is_atom(prefix)) and is_integer(amount) do
-    nodes = Enum.map(1..amount, fn idx ->
-      { :ok, name } = :slave.start_link(
-        '127.0.0.1',
-        :"#{prefix}#{idx}",
-        '-loader inet -hosts 127.0.0.1 -setcookie "#{:erlang.get_cookie()}"'
-      )
-      name
-    end)
+      when (is_binary(prefix) or is_atom(prefix)) and is_integer(amount) do
+    root_app = Keyword.get(options, :root_app)
+
+    nodes =
+      Enum.map(1..amount, fn idx ->
+        {:ok, name} =
+          :slave.start_link(
+            '127.0.0.1',
+            :"#{prefix}#{idx}",
+            '-loader inet -hosts 127.0.0.1 -setcookie "#{:erlang.get_cookie()}"'
+          )
+
+        name
+      end)
 
-    rpc = &({ _, [] } = :rpc.multicall(nodes, &1, &2, &3))
+    rpc = &({_, []} = :rpc.multicall(nodes, &1, &2, &3))
 
-    rpc.(:code, :add_paths, [ :code.get_path() ])
+    rpc.(:code, :add_paths, [:code.get_path()])
 
-    rpc.(Application, :ensure_all_started, [ :mix ])
-    rpc.(Application, :ensure_all_started, [ :logger ])
+    rpc.(Application, :ensure_all_started, [:mix])
+    rpc.(Application, :ensure_all_started, [:logger])
 
-    rpc.(Logger, :configure, [ level: Logger.level() ])
-    rpc.(Mix, :env, [ Mix.env() ])
+    rpc.(Logger, :configure, level: Logger.level())
+    rpc.(Mix, :env, [Mix.env()])
 
-    for { app_name, _, _ } <- Application.loaded_applications() do
-      for { key, val } <- Application.get_all_env(app_name) do
-        rpc.(Application, :put_env, [ app_name, key, val ])
+    for {app_name, _, _} <- Application.loaded_applications() do
+      for {key, val} <- Application.get_all_env(app_name) do
+        rpc.(Application, :put_env, [app_name, key, val])
       end
-      rpc.(Application, :ensure_all_started, [ app_name ])
+
+      unless root_app do
+        rpc.(Application, :ensure_all_started, [app_name])
+      end
+    end
+
+    if root_app do
+      rpc.(Application, :ensure_all_started, [root_app])
     end
 
     for file <- Keyword.get(options, :files, []) do
-      { :ok, source } = File.read(file)
+      {:ok, source} = File.read(file)
 
-      for { module, binary } <- Code.compile_string(source, file) do
+      for {module, binary} <- Code.compile_string(source, file) do
         rpc.(:code, :load_binary, [
           module,
           :unicode.characters_to_list(file),
@@ -90,14 +104,14 @@ defmodule LocalCluster do
   @doc """
   Stops a set of child nodes.
   """
-  @spec stop_nodes([ atom ]) :: :ok
+  @spec stop_nodes([atom]) :: :ok
   def stop_nodes(nodes) when is_list(nodes),
     do: Enum.each(nodes, &:slave.stop/1)
 
   @doc """
   Stops the current distributed node and turns it back into a local node.
   """
-  @spec stop :: :ok | { :error, atom }
+  @spec stop :: :ok | {:error, atom}
   def stop,
     do: :net_kernel.stop()
 end