Target - Targeted Property-Based Testing

Target adds a search-based strategy component to PropEr's input generation process, which helps in finding counterexamples faster in properties that aim to maximize (or minimize) the value of some variable of the property.

Simple Example

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

prop_example_target() ->
  ?TARGET_STRATEGY(target_sa,
      ?FORALL(X, ?TARGET(target_sa:float(0.0, 10000.0)),
              begin
                ?MAXIMIZE(X),
                X < 9990.0
	      end)).

%% prop_example() ->
%%  ?FORALL(X, float(0.0, 10000.0), X < 9990.0).

Target will be able to falsify properties like these much faster than vanilla PropEr.

put(target_sa_steps, 10000).
proper:quickcheck(prop_example_target(), 10000).