test: improve proper test so it generates more cases

apps/emqx_rule_engine/test/emqx_rule_funcs_SUITE.erl

@@ -959,7 +959,7 @@ prop_format_date_fun() ->
     Args1 = [<<"second">>, <<"+07:00">>, <<"%m--%d--%y---%H:%M:%S%Z">>],
     ?FORALL(
         S,
-        erlang:system_time(second),
+        range(0, 4000000000),
         S ==
             apply_func(
                 date_to_unix_ts,
@@ -975,7 +975,7 @@ prop_format_date_fun() ->
     Args2 = [<<"millisecond">>, <<"+04:00">>, <<"--%m--%d--%y---%H:%M:%S%Z">>],
     ?FORALL(
         S,
-        erlang:system_time(millisecond),
+        range(0, 4000000000),
         S ==
             apply_func(
                 date_to_unix_ts,
@@ -991,7 +991,7 @@ prop_format_date_fun() ->
     Args = [<<"second">>, <<"+08:00">>, <<"%y-%m-%d-%H:%M:%S%Z">>],
     ?FORALL(
         S,
-        erlang:system_time(second),
+        range(0, 4000000000),
         S ==
             apply_func(
                 date_to_unix_ts,
@@ -1009,7 +1009,7 @@ prop_format_date_fun() ->
     ArgsOffset = [<<"second">>, <<"+08:00">>, <<"%y-%m-%d-%H:%M:%S%Z">>],
     ?FORALL(
         S,
-        erlang:system_time(second),
+        range(0, 4000000000),
         S ==
             apply_func(
                 date_to_unix_ts,