Format string.ex and improve upcase coverage

Author: José Valim

lib/elixir/lib/string.ex

@@ -641,8 +641,8 @@ defmodule String do
 
   def upcase(string, :ascii) when is_binary(string) do
     for <<x <- string>>,
-        do: if(x >= ?a and x <= ?z, do: <<x - 32>>, else: <<x>>),
-        into: ""
+      do: if(x >= ?a and x <= ?z, do: <<x - 32>>, else: <<x>>),
+      into: ""
   end
 
   def upcase(string, mode) when mode in @conditional_mappings do
@@ -693,8 +693,8 @@ defmodule String do
 
   def downcase(string, :ascii) when is_binary(string) do
     for <<x <- string>>,
-        do: if(x >= ?A and x <= ?Z, do: <<x + 32>>, else: <<x>>),
-        into: ""
+      do: if(x >= ?A and x <= ?Z, do: <<x + 32>>, else: <<x>>),
+      into: ""
   end
 
   def downcase(string, mode) when mode in @conditional_mappings do

lib/elixir/test/elixir/string_test.exs

@@ -149,6 +149,10 @@ defmodule StringTest do
     assert String.upcase("áüÈß") == "ÁÜÈSS"
   end
 
+  test "upcase/1 with ascii" do
+    assert String.upcase("olá", :ascii) == "OLá"
+  end
+
   test "downcase/1" do
     assert String.downcase("123 ABcD 456 EfG HIJ ( %$#) KL MNOP @ QRST = -_ UVWXYZ") ==
              "123 abcd 456 efg hij ( %$#) kl mnop @ qrst = -_ uvwxyz"