Extracts modules for different sections of the UI

lib/display/failure.ex

@@ -0,0 +1,35 @@
+defmodule Display.Failure do
+  @no_value :ex_unit_no_meaningful_value
+
+  def format_failure(%{error: %ExUnit.AssertionError{expr: @no_value, message: message}, file: file, line: line}) do
+    """
+    #{Colours.cyan("Assertion failed in #{file}:#{line}")}
+    #{Colours.red(message)}
+    """
+  end
+  def format_failure(%{error: %ExUnit.AssertionError{expr: expr}, file: file, line: line}) do
+    format_assertion_error(expr, file, line)
+  end
+  def format_failure(%{error: error, file: file, line: line}) do
+    """
+    #{Colours.cyan("Error in #{file}:#{line}")}
+    #{format_error(error)}
+    """
+  end
+
+  defp format_assertion_error(error, file, line) do
+    """
+    #{Colours.cyan("Assertion failed in #{file}:#{line}")}
+    #{Colours.red(Macro.to_string(error))}
+    """
+  end
+
+  defp format_error(error) do
+    trace = System.stacktrace |> Enum.take(2)
+    Colours.red(Exception.format(:error, error, trace))
+  end
+
+  def show_compile_error(error) do
+    format_error(error)
+  end
+end