Improvements and tests

Co-authored-by: Jan Uhlig <juhlig@hnc-agency.org>

Author: Maria-12648430

include/proper.hrl

@@ -46,10 +46,10 @@
 %% Basic types
 %%------------------------------------------------------------------------------
 
--import(proper_types, [integer/2, float/2, atom/0, binary/0, binary/1,
-		       bitstring/0, bitstring/1, list/1, vector/2, union/1,
-		       weighted_union/1, tuple/1, loose_tuple/1, exactly/1,
-		       fixed_list/1, function/2, map/2, any/0]).
+-import(proper_types, [integer/2, float/2, atom/0, existing_atom/0, binary/0,
+		       binary/1,  bitstring/0, bitstring/1, list/1, vector/2,
+		       union/1, weighted_union/1, tuple/1, loose_tuple/1,
+		       exactly/1, fixed_list/1, function/2, map/2, any/0]).
 
 
 %%------------------------------------------------------------------------------

src/proper_gen.erl

@@ -46,7 +46,7 @@
 	 any_gen/1, native_type_gen/2, safe_weighted_union_gen/1,
 	 safe_union_gen/1]).
 
--export([existing_atom_gen/1]).
+-export([existing_atom_gen/0]).
 
 %% Public API types
 -export_type([instance/0, seed/0, size/0]).
@@ -421,10 +421,10 @@ atom_rev(Atom) ->
     {'$used', atom_to_list(Atom), Atom}.
 
 %% @private
--spec existing_atom_gen(size()) -> atom().
+-spec existing_atom_gen() -> atom().
 %% We make sure we never clash with internal atoms by ignoring atoms starting with
 %% the character '$'.
-existing_atom_gen(_Size) ->
+existing_atom_gen() ->
     case get('$existing_atoms') of
         undefined ->
             {NextIndex, Atoms} = get_existing_atoms(0, #{}),

src/proper_types.erl

@@ -683,7 +683,7 @@ atom() ->
 -spec existing_atom() -> proper_types:type().
 existing_atom() ->
     ?BASIC([
-        {generator, fun proper_gen:existing_atom_gen/1},
+        {generator, fun proper_gen:existing_atom_gen/0},
 	{reverse_gen, fun proper_gen:atom_rev/1},
 	{is_instance, fun atom_is_instance/1},
 	{noshrink, true}

src/proper_typeserver.erl

@@ -187,9 +187,9 @@
 
 %% CAUTION: all these must be sorted
 -define(STD_TYPES_0,
-	[any,arity,atom,binary,bitstring,bool,boolean,byte,char,float,integer,
-	 list,neg_integer,nil,non_neg_integer,number,pos_integer,string,term,
-	 timeout]).
+	[any,arity,atom,binary,bitstring,bool,boolean,byte,char,existing_atom,
+	 float,integer,list,neg_integer,nil,non_neg_integer,number,pos_integer,
+	 string,term,timeout]).
 -define(HARD_ADTS,
 	%% gb_trees:iterator and gb_sets:iterator are NOT hardcoded
 	[{{array,0},array},      {{array,1},proper_array},

test/proper_tests.erl

@@ -1398,6 +1398,16 @@ sampleshrink_test_() ->
         ?_shrinksTo([a], Gen)},
        ?_test(proper_gen:sampleshrink(Gen))]}].
 
+existing_atom_test() ->
+    N = erlang:system_info(atom_count),
+    {ok, Atom} = proper_gen:pick(proper_types:existing_atom()),
+    ?assert(erlang:is_atom(Atom)),
+    ?assertEqual(N, erlang:system_info(atom_count)).
+
+default_atom_test() ->
+    N = erlang:system_info(atom_count),
+    ?assert(proper:quickcheck(?FORALL(_, any(), true), [{default_atom_generator, existing_atom}])),
+    ?assertEqual(N, erlang:system_info(atom_count)).
 
 %%------------------------------------------------------------------------------
 %% Performance tests