add .formatter.exs + format

test/test_helper.exs

@@ -23,10 +23,10 @@ defmodule TestHarness do
   end
 
   defp check_results(results) do
-    Enum.each(results, &(assert &1 == :passed))
+    Enum.each(results, &assert(&1 == :passed))
   end
 
   def run_all(pairs, module) do
-    Enum.map(pairs, fn ({koan, answer}) -> Execute.run_koan(module, koan, [answer]) end)
+    Enum.map(pairs, fn {koan, answer} -> Execute.run_koan(module, koan, [answer]) end)
   end
 end