Improvements to File.ls implementation

Author: José Valim

lib/elixir/lib/file.ex

@@ -897,44 +897,30 @@ defmodule File do
     end
   end
 
+  @doc """
+  Returns list of files in the given directory.
 
-@doc """
-  Returns list of files in the current working directory. In rare circumstances, this function can
-  fail on Unix. It may happen if read permission does not exist for the parent
-  directories of the current directory. For this reason, returns `{ :ok, [files] }`
-  in case of success, `{ :error, reason }` otherwise.
-  """
-  def ls() do
-    ls(".")
-  end
-
-@doc """
-  Returns list of files in the given directory. In rare circumstances, this function can
-  fail on Unix. It may happen if read permission does not exist for the parent
-  directories of the current directory. For this reason, returns `{ :ok, [files] }`
-  in case of success, `{ :error, reason }` otherwise.
+  It returns `{ :ok, [files] }` in case of success,
+  `{ :error, reason }` otherwise.
   """
-  def ls(path) do
+  def ls(path // ".") do
     case F.list_dir(path) do
       { :ok, file_list } -> { :ok, Enum.map file_list, :unicode.characters_to_binary(&1) }
       { :error, _ } = error -> error
     end
   end
 
-
   @doc """
-  Get list of files in directories in `dir`.
- 
-  Raises File.Error in case of an error.
+  The same as `ls/1` but raises `File.Error`
+  in case of an error.
   """
-  def ls!(dir) do
-    case F.list_dir(dir) do
-      { :ok, file_list } -> Enum.map file_list, :unicode.characters_to_binary(&1)
+  def ls!(dir // ".") do
+    case ls(dir) do
+      { :ok, value } -> value
       { :error, reason } ->
         raise File.Error, reason: reason, action: "list directory", path: :unicode.characters_to_binary(dir)
     end
   end
-  
 
   @doc """
   Closes the file referenced by `io_device`. It mostly returns `:ok`, except

lib/elixir/test/elixir/file_test.exs

@@ -398,32 +398,23 @@ defmodule FileTest do
   end
 
   test :ls do
-    {code, value} = File.ls(fixture_path)
-    assert code == :ok
-    refute code == :error
-    assert is_list value
-    assert 0 < Enum.count(value) 
+    { :ok, value } = File.ls(fixture_path)
     assert List.member?(value, "code_sample.exs")
     assert List.member?(value, "file.txt")
-    {code2, reason} = File.ls(fixture_path("non-existent-subdirectory"))
-    refute code2 == :ok
-    assert code2 == :error
-    assert reason != nil
+
+    { :error, :enoent } = File.ls(fixture_path("non-existent-subdirectory"))
   end
 
-  test :ls2 do
+  test :ls! do
     value = File.ls!(fixture_path)
-    assert is_list value
-    assert 0 < Enum.count(value) 
     assert List.member?(value, "code_sample.exs")
     assert List.member?(value, "file.txt")
+
     assert_raise File.Error, fn ->
-        File.ls!(fixture_path("non-existent-subdirectory"))
+      File.ls!(fixture_path("non-existent-subdirectory"))
     end
   end
 
-
-
   defmodule OpenReadWrite do
     use ExUnit.Case