Expand docs and examples

lib/phoenix/test/conn_test.ex

@@ -639,7 +639,7 @@ defmodule Phoenix.ConnTest do
 
   Useful for testing actions that you expect raise an error and have
   the response wrapped in an HTTP status, with content usually rendered
-  by your MyApp.ErrorView.
+  by your MyAppWeb.ErrorHTML view.
 
   The function accepts a status either as an integer HTTP status or
   atom, such as `500` or `:internal_server_error`. The list of allowed atoms is available
@@ -658,6 +658,19 @@ defmodule Phoenix.ConnTest do
         get(build_conn(), "/broken/route")
       end
       assert {500, [_h | _t], "Internal Server Error"} = response
+
+  This can also be used to test a route resulted in an error that was translated to a
+  specific response by the `Plug.Status` protocol, such as `Ecto.NoResultsError`:
+
+      assert_error_sent :not_found, fn ->
+        get(build_conn(), "/something-that-raises-no-results-error")
+      end
+
+  *Note*: for routes that don't raise an error, but instead return a status, you should test the
+  response directly:
+
+      conn = get(build_conn(), "/users/not-found")
+      assert response(conn, 404)
   """
   @spec assert_error_sent(integer | atom, function) :: {integer, list, term}
   def assert_error_sent(status_int_or_atom, func) do