@type last_result() :: result() | nil

@type observed() :: %{optional(String.t() | atom()) => term()}

@type operation() ::
  :visit
  | :click
  | :fill_in
  | :select
  | :choose
  | :check
  | :uncheck
  | :upload
  | :submit
  | :assert_has
  | :refute_has
  | :assert_path
  | :refute_path
  | :unwrap

@type result() :: %{
  op: operation(),
  observed: observed() | nil,
  transition: transition() | nil
}

@type scope_value() :: String.t() | observed() | nil

@type t() :: struct()

@type transition() :: observed()