Stateful property tests for the server

src/opuntia_srv.erl

@@ -11,12 +11,12 @@
 -export([start_link/2, wait/4, reset_shapers/1]).
 
 %% gen_server Function Exports
--export([init/1, handle_call/3, handle_cast/2, handle_info/2, terminate/2, code_change/3]).
+-export([init/1, handle_call/3, handle_cast/2, handle_info/2]).
 
 %% Record definitions
 -record(opuntia_state, {
  name :: name(),
- max_delay :: opuntia:rate(), %% Maximum amount of time units to wait
+ max_delay :: opuntia:delay(), %% Maximum amount of time units to wait
  gc_ttl :: non_neg_integer(), %% How many seconds to store each shaper
  gc_time :: non_neg_integer(), %% How often to run the gc
  gc_ref :: undefined | reference(),
@@ -26,7 +26,7 @@
 -type name() :: atom().
 -type key() :: term().
 -type seconds() :: non_neg_integer().
--type args() :: #{max_delay => opuntia:rate(),
+-type args() :: #{max_delay => opuntia:delay(),
  gc_interval => seconds(),
  ttl => seconds()}.
 -type maybe_rate() :: fun(() -> opuntia:rate() | opuntia:rate()).
@@ -40,11 +40,11 @@ start_link(Name, Args) ->
 -spec wait(gen_server:server_ref(), key(), opuntia:tokens(), maybe_rate()) ->
  continue | {error, max_delay_reached}.
 wait(Shaper, Key, Tokens, Config) ->
- gen_server:call(Shaper, {wait, Key, Tokens, Config}).
+ gen_server:call(Shaper, {wait, Key, Tokens, Config}, infinity).
 
 %% @doc Ask server to forget its shapers
 reset_shapers(ProcName) ->
- gen_server:call(ProcName, reset_shapers).
+ gen_server:call(ProcName, reset_shapers, infinity).
 
 %% gen_server Function Definitions
 -spec init({name(), args()}) -> {ok, opuntia_state()}.
@@ -95,12 +95,6 @@ handle_info(Info, #opuntia_state{name = Name} = State) ->
  telemetry:execute([opuntia, unknown_request, Name], #{value => 1}, #{msg => Info, type => info}),
  {noreply, State}.
 
-terminate(_Reason, _State) ->
- ok.
-
-code_change(_OldVsn, State, _Extra) ->
- {ok, State}.
-
 %% ------------------------------------------------------------------
 %% Internal Function Definitions
 %% ------------------------------------------------------------------
@@ -122,10 +116,9 @@ save_shaper(#opuntia_state{shapers = Shapers} = State, Key, Shaper) ->
 cleanup(State = #opuntia_state{name = Name, shapers = Shapers, gc_ttl = TTL}) ->
  telemetry:execute([opuntia, cleanup, Name], #{}, #{}),
  TimestampThreshold = erlang:system_time(second) - TTL,
- F = fun(_, #token_bucket{last_update = ATime}) ->
- Min = erlang:convert_time_unit(TimestampThreshold, second, millisecond),
- ATime > Min
- end,
+ Min = erlang:convert_time_unit(TimestampThreshold, second, millisecond),
+ F = fun(_, #token_bucket{last_update = ATime}) -> ATime > Min;
+ (_, none) -> false end,
  RemainingShapers = maps:filter(F, Shapers),
  State#opuntia_state{shapers = RemainingShapers}.
 

test/opuntia_SUITE.erl

@@ -12,8 +12,8 @@
  init_per_testcase/2,
  end_per_testcase/2]).
 
--include_lib("stdlib/include/assert.hrl").
 -include_lib("proper/include/proper.hrl").
+-include_lib("common_test/include/ct.hrl").
 
 all() ->
  [
@@ -25,13 +25,15 @@ groups() ->
  {throughput_throttle, [parallel],
  [
  run_shaper_with_zero_does_not_shape,
- run_basic_shaper_property
+ run_basic_shaper_property,
+ run_stateful_server
  ]}
  ].
 
 %%%===================================================================
 %%% Overall setup/teardown
 %%%===================================================================
+
 init_per_suite(Config) ->
  ct:pal("Online schedulers ~p~n", [erlang:system_info(schedulers_online)]),
  application:ensure_all_started(telemetry),
@@ -46,20 +48,30 @@ init_per_group(_, Config) ->
 end_per_group(_Groupname, _Config) ->
  ok.
 
+init_per_testcase(run_stateful_server, Config) ->
+ [{{pid, run_stateful_server}, spawn(fun keep_table/0)} | Config];
 init_per_testcase(_TestCase, Config) ->
  Config.
 
+end_per_testcase(run_stateful_server, Config) ->
+ Pid = ?config({pid, run_stateful_server}, Config),
+ Pid ! clean_table;
 end_per_testcase(_TestCase, _Config) ->
  ok.
 
+keep_table() ->
+ ets:new(?MODULE, [named_table, set, public,
+ {write_concurrency, true}, {read_concurrency, true}]),
+ receive Msg -> Msg end.
+
 %%%===================================================================
 %%% Individual Test Cases (from groups() definition)
 %%%===================================================================
 
 run_shaper_with_zero_does_not_shape(_) ->
  Prop = ?FORALL(
  TokensToSpend,
- integer(1, 9999),
+ tokens(),
  begin
  Shaper = opuntia:new(0),
  {TimeUs, _LastShaper} = timer:tc(fun run_shaper/2, [Shaper, TokensToSpend]),
@@ -71,7 +83,7 @@ run_shaper_with_zero_does_not_shape(_) ->
 run_basic_shaper_property(_) ->
  Prop = ?FORALL(
  {TokensToSpend, RatePerMs},
- {integer(1, 9999), integer(1, 9999)},
+ {tokens(), rate()},
  begin
  Shaper = opuntia:new(RatePerMs),
  {TimeUs, _LastShaper} = timer:tc(fun run_shaper/2, [Shaper, TokensToSpend]),
@@ -82,8 +94,94 @@ run_basic_shaper_property(_) ->
  [TokensToSpend, RatePerMs, TimeMs, MinimumExpected, Val]),
  Val
  end),
- run_prop(?FUNCTION_NAME, Prop).
+ run_prop(?FUNCTION_NAME, Prop, 100_000, 256).
+
+%%%===================================================================
+%% Server stateful property
+%%%===================================================================
+
+run_stateful_server(_) ->
+ Prop =
+ ?FORALL(Cmds, commands(?MODULE),
+ begin
+ Config = #{max_delay => 99999, gc_interval => 1},
+ {ok, Pid} = opuntia_srv:start_link(?MODULE, Config),
+ {History, State, Res} = run_commands(?MODULE, Cmds, [{server, Pid}]),
+ ?WHENFAIL(io:format("H: ~p~nS: ~p~n Res: ~p~n", [History, State, Res]), Res == ok)
+ end),
+ run_prop(?FUNCTION_NAME, Prop, 10_000, 256).
+
+command(_State) ->
+ oneof([
+ {call, ?MODULE, wait, [{var, server}, key(), tokens(), config()]},
+ {call, ?MODULE, reset_shapers, [{var, server}]}
+ ]).
+
+
+initial_state() ->
+ #{}.
+
+precondition(_State, {call, ?MODULE, reset_shapers, [_Server]}) ->
+ true;
+precondition(State, {call, ?MODULE, wait, [Server, Key, _Tokens, Config]}) ->
+ case maps:is_key(Key, State) of
+ true -> %% We already know when this one started
+ true;
+ false -> %% Track start for this key
+ Now = erlang:monotonic_time(millisecond),
+ Rate = get_rate_from_config(Config),
+ ets:insert(?MODULE, {{Server, Key}, Rate, Now}),
+ true
+ end.
+
+postcondition(_State, {call, ?MODULE, reset_shapers, [_Server]}, Res) ->
+ ok =:= Res;
+postcondition(State, {call, ?MODULE, wait, [Server, Key, Tokens, _Config]}, Res) ->
+ Now = erlang:monotonic_time(millisecond),
+ [{_, Rate, Start}] = ets:lookup(?MODULE, {Server, Key}),
+ TokensNowConsumed = tokens_now_consumed(State, Key, Tokens),
+ MinimumExpected = calculate_accepted_range(TokensNowConsumed, Rate),
+ Duration = Now - Start,
+ continue =:= Res andalso MinimumExpected =< Duration.
+
+next_state(_State, _Result, {call, ?MODULE, reset_shapers, [_Server]}) ->
+ #{};
+next_state(State, _Result, {call, ?MODULE, wait, [_Server, Key, Tokens, _Config]}) ->
+ TokensNowConsumed = tokens_now_consumed(State, Key, Tokens),
+ State#{Key => TokensNowConsumed}.
+
+tokens_now_consumed(State, Key, NewTokens) ->
+ TokensConsumedSoFar = maps:get(Key, State, 0),
+ TokensConsumedSoFar + NewTokens.
+
+wait(Shaper, Key, Tokens, Config) ->
+ opuntia_srv:wait(Shaper, Key, Tokens, Config).
+
+reset_shapers(Shaper) ->
+ opuntia_srv:reset_shapers(Shaper).
+
+get_rate_from_config(N) when is_integer(N), N >= 0 ->
+ N;
+get_rate_from_config(Config) when is_function(Config, 0) ->
+ Config().
 
+key() ->
+ binary().
+
+tokens() ->
+ integer(1, 9999).
+
+config() ->
+ union([0, rate(), function(0, rate())]).
+
+rate() ->
+ integer(1, 9999).
+
+%%%===================================================================
+%% Helpers
+%%%===================================================================
+calculate_accepted_range(_, 0) ->
+ 0;
 calculate_accepted_range(TokensToSpend, RatePerMs) when TokensToSpend =< RatePerMs ->
  0;
 calculate_accepted_range(TokensToSpend, RatePerMs) ->
@@ -98,15 +196,6 @@ run_shaper(Shaper, TokensLeft) ->
  timer:sleep(DelayMs),
  run_shaper(NewShaper, TokensLeft - TokensConsumed).
 
-
-
-
-run_prop(PropName, Property) ->
- run_prop(PropName, Property, 100_000).
-
-run_prop(PropName, Property, NumTests) ->
- run_prop(PropName, Property, NumTests, 256).
-
 run_prop(PropName, Property, NumTests, WorkersPerScheduler) ->
  Opts = [quiet, noshrink, long_result, {start_size, 2}, {numtests, NumTests},
  {numworkers, WorkersPerScheduler * erlang:system_info(schedulers_online)}],