 
     %{module: mod, function: {name, arity}, file: file, line: line} = __ENV__
 
-    log = capture_log(fn ->
-      Logger.debug("hello")
-    end)
+    log =
+      capture_log(fn ->
+        Logger.debug("hello")
+      end)
 
     assert log =~ "file=#{file}"
     assert log =~ "line=#{line + 3}"

  import ExUnit.CaptureIO

  setup do
    on_exit fn ->
      :ok = Logger.configure_backend(:console,
              [format: nil, device: :user, level: nil, metadata: [], colors: [enabled: false]])
    end
  end

  test "does not start when there is no user" do

    Logger.configure_backend(:console, device: :standard_error)

    assert capture_io(:standard_error, fn ->
             Logger.debug("hello")
             Logger.flush()
           end) =~ "hello"
  end

  test "can configure format" do
    Logger.configure_backend(:console, format: "$message [$level]")

    assert capture_log(fn ->
             Logger.debug("hello")
           end) =~ "hello [debug]"
  end

  test "can configure metadata" do
    Logger.configure_backend(:console, format: "$metadata$message", metadata: [:user_id])

    assert capture_log(fn ->
             Logger.debug("hello")
           end) =~ "hello"

    Logger.metadata(user_id: 11)
    Logger.metadata(user_id: 13)

    assert capture_log(fn ->
             Logger.debug("hello")
           end) =~ "user_id=13 hello"
  end

  test "can configure formatter to {module, function} tuple" do
    Logger.configure_backend(:console, format: {__MODULE__, :format})

    assert capture_log(fn ->
             Logger.debug("hello")
           end) =~ "my_format: hello"
  end

  def format(_level, message, _ts, _metadata) do
