emqx4.3/apps/emqx_rule_engine/test/prop_rule_maps.erl

-module(prop_rule_maps).

-include_lib("proper/include/proper.hrl").

prop_get_put_single_key() ->
    ?FORALL({Key, Val}, {term(), term()},
            begin
                Val =:= emqx_rule_maps:nested_get({var, Key},
                            emqx_rule_maps:nested_put({var, Key}, Val, #{}))
            end).