Extract display for formatting purposes

lib/display.ex

@@ -0,0 +1,40 @@
+defmodule Display do
+  alias IO.ANSI
+
+  def show_failure(%{expr: expr}, module, name) do
+    source = module.__info__(:compile)
+              |> Dict.get(:source)
+              |> Path.relative_to(File.cwd!)
+    IO.puts("")
+    IO.puts("Now meditate upon #{display_module(module)}")
+    IO.puts("---------------------------------------")
+    IO.puts("Assertion failed in #{source}:#{line_number(expr)}")
+    IO.puts(display_koan(name))
+    IO.puts(format_red(Macro.to_string(expr)))
+  end
+
+  def considering(module) do
+    IO.puts("Considering #{display_module(module)}...")
+  end
+
+  def before_run do
+    IO.puts("")
+    IO.puts("")
+  end
+
+  defp line_number({_, [line: line], _}) do
+    line
+  end
+
+  defp format_red(str) do
+    Enum.join([ANSI.red, str, ANSI.reset], "")
+  end
+
+  defp display_module(module) do
+    Module.split(module) |> List.last
+  end
+
+  defp display_koan(name) do
+    String.replace(to_string(name), "koan: ", "")
+  end
+end