Document and test Logger functions return :ok

Author: José Valim

lib/logger/lib/logger.ex

@@ -235,6 +235,7 @@ defmodule Logger do
   def metadata(dict) do
     {enabled, metadata} = __metadata__()
     Process.put(@metadata, {enabled, Keyword.merge(metadata, dict)})
+    :ok
   end
 
   @doc """
@@ -251,6 +252,7 @@ defmodule Logger do
   """
   def enable(pid) when pid == self() do
     Process.put(@metadata, {true, metadata()})
+    :ok
   end
 
   @doc """
@@ -260,6 +262,7 @@ defmodule Logger do
   """
   def disable(pid) when pid == self() do
     Process.put(@metadata, {false, metadata()})
+    :ok
   end
 
   @doc """

lib/logger/test/logger_test.exs

@@ -65,25 +65,25 @@ defmodule LoggerTest do
   end
 
   test "enable/1 and disable/1" do
-    Logger.metadata([])
+    assert Logger.metadata([]) == :ok
 
     assert capture_log(fn ->
       assert Logger.debug("hello", []) == :ok
     end) =~ msg("[debug] hello")
 
-    Logger.disable(self())
+    assert Logger.disable(self()) == :ok
 
     assert capture_log(fn ->
       assert Logger.debug("hello", []) == :ok
     end) == ""
 
-    Logger.metadata([])
+    assert Logger.metadata([]) == :ok
 
     assert capture_log(fn ->
       assert Logger.debug("hello", []) == :ok
     end) == ""
 
-    Logger.enable(self())
+    assert Logger.enable(self()) == :ok
 
     assert capture_log(fn ->
       assert Logger.debug("hello", []) == :ok