/*  Part of SWI-Prolog

    Author:        Jan Wielemaker
    E-mail:        J.Wielemaker@vu.nl
    WWW:           http://www.swi-prolog.org
    Copyright (c)  2008-2020, University of Amsterdam
                              VU University Amsterdam
    All rights reserved.

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    modification, are permitted provided that the following conditions
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       notice, this list of conditions and the following disclaimer.

    2. Redistributions in binary form must reproduce the above copyright
       notice, this list of conditions and the following disclaimer in
       the documentation and/or other materials provided with the
       distribution.

    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
    "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
    FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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*/

:- module(test_term, [test_term/0]).
:- use_module(library(plunit)).
:- use_module(library(debug)).

/** <module> Test Prolog core term manipulation primitives

This module is a Unit test for  Prolog built-ins that process terms,
such as numbervars, univ, etc.

@author	Jan Wielemaker
*/

test_term :-
	run_tests([ numbervars,
		    variant,
		    compound,
		    zero_arity_compound,
		    term_singletons
		  ]).

:- begin_tests(numbervars).

test(single, End == 1) :-
	numbervars(_, 0, End).
test(single_s, End == 0) :-
	numbervars(_, 0, End, [singletons(true)]).
test(single_offset, End == 1001) :-
	numbervars(f(A,_B,A), 1000, End, [singletons(true)]),
	assertion(arg(1, A, 1000)).
test(single_lr, End == 3) :-		% consistent LR numbering
	numbervars(t(A,B,A,C,C,B), 0, End, [singletons(true)]),
	assertion(arg(1, A, 0)),
	assertion(arg(1, B, 1)),
	assertion(arg(1, C, 2)).
test(single_lr, End == 3) :-		% consistent LR numbering
	numbervars(t(A,B,S,A,C,C,B), 0, End, [singletons(true)]),
	assertion(arg(1, S, '_')),
	assertion(arg(1, A, 0)),
	assertion(arg(1, B, 1)),
	assertion(arg(1, C, 2)).
test(neg, End == -6) :-
	numbervars(f(X), -7, End),
	assertion(X == '$VAR'(-7)).
test(shared, End == 1) :-
	X = d(_),
	Y = t(X,X),
	numbervars(Y, 0, End, []).
test(shared_s, End == 1) :-
	X = d(_),
	Y = t(X,X),
	numbervars(Y, 0, End, [singletons(true)]).
test(cyclic, [sto(rational_trees), End == 1]) :-
	X = d(X, _),
	numbervars(X, 0, End, []).
% currently singletons(true) is ignored for cyclic terms
test(cyclic_s, [sto(rational_trees), End == 1]) :-
	X = d(X, _),
	numbervars(X, 0, End, [singletons(true)]).
test(twice_singleton, X == '$VAR'('_')) :-
	T = a(X),
	numbervars(T, 0, _E1, [singletons(true)]),
	numbervars(T, 0, _E2, [singletons(true)]).
test(shift, true) :-
	between(1, 20, X),
	trim_stacks,
	Len is 1<<X,
	length(List, Len),
	statistics(global_shifts, S0),
	numbervars(List, 0, _),
	statistics(global_shifts, S1),
	S1 > S0, !.

:- end_tests(numbervars).


:- begin_tests(variant).

test(simple) :-
	v(A), v(B),
	a(A) =@= a(B).
test(shared) :-
	a(A) =@= a(A).
test(shared) :-
	a(A, A) =@= a(A, A).
test(shared) :-
	a(A, B) =@= a(A, B).
test(shared, fail) :-
	v(B),
	a(A, B) =@= a(A, A).
test(shared, fail) :-
	v(A),
	a(A, B) =@= a(B, B).
test(dubious, true) :-
	v(X), v(Z),
	a(X, Y) =@= a(Y, Z).
test(common, true) :-			% Bug #464
	A=x(_),
	s(A, A) =@= s(x(B), x(B)).
test(common, fail) :-
	X = x(A), v(B),
	a(X,A) =@= a(X,B).
test(common, fail) :-
	X = x(A), v(B),
	a(A,X) =@= a(B,X).
test(cyclic, [sto(rational_trees)]) :-
	A = f(A),
	A =@= f(A).
test(cyclic, [fail, sto(rational_trees)]) :-
	S = s(S),
	S =@= s(s(s(s(1)))).
test(cyclic, [sto(rational_trees)]) :-
	S = s(s(S)), X = s(s(s(X))),
	S =@= X.
test(cyclic, [sto(rational_trees)]) :-
	S = s(x(S)), X = s(x(s(x(X)))),
	S =@= X.
test(shared, fail) :-
	v(A), v(B),
	X = x(A), Y = x(B),
	s(X,Y,X) =@= s(X,Y,Y).
test(cycle, [sto(rational_trees), fail]) :- % Ulrich
	A=[_V1,_V2|A], D=[_V3|A],
	A =@= D.
test(symmetry, [fail]) :-		    % Ulrich
	A=[B|C], D=[C|B],
	B=[X|_Y], C=[_Z|X],
	A =@= D.
test(symmetry, [fail]) :-		    % Ulrich
	X=s(_Xi), Y=s(_Yi), Z=s(_Zi),
	A=v(X,Y,X), D=v(Z,X,Y),
	A =@= D.
test(ground, [sto(rational_trees), fail]) :- % Ulrich
	A=[A|B], B=[A], D=[[A|B]|A],
	A = [_,_], D = [_,_,_],
	A =@= D.
test(sharing_cycles, [sto(rational_trees), fail]) :-
	A=[A|B], C=[A|D], B=[A|E], F=[A|F], D=[F|E],
	A =@= C.
test(cycle_with_prefix, [sto(rational_trees), fail]) :-
	A = [A|_],
	X = [A|Y],
	B = [X|Y],
	A =@= B.

v(_).

:- end_tests(variant).


:- begin_tests(compound).

test(functor, error(domain_error(_,_))) :-
	functor(a(), _, _).
test(=.., error(domain_error(_,_))) :-
	a() =.. _.
test(=.., error(type_error(atomic,f(a)))) :-
	_Var =.. [f(a)].
test(compound_name_arity, A == 0) :-
	compound_name_arity(a(), _N, A).
test(compound_name_arity, T == a()) :-
	compound_name_arity(T, a, 0).
test(compound_name_arity, T =@= a(_)) :-
	compound_name_arity(T, a, 1).
test(compound_name_arity, error(type_error(compound,a))) :-
	compound_name_arity(a, _, _).
test(compound_name_arguments, T == a()) :-
	compound_name_arguments(T, a, []).
test(compound_name_arguments, Args == []) :-
	compound_name_arguments(a(), _N, Args).

:- end_tests(compound).

:- begin_tests(zero_arity_compound).

:- '$clausable'((t1/1,t2/1,t3/1,t4/1,t5/1)).

t1(A) :- t(A,a()).
t2(A) :- t(a(),A).
t3(a()).
t4(a(1, a())).
t5(a(a(),1)).

t(X,X).

test(clause, B == t(A,a())) :-
	clause(t1(A), B).
test(clause, B == t(a(),A)) :-
	clause(t2(A), B).
test(clause, A == a()) :-
	clause(t3(A), true).
test(clause, A == a(1,a())) :-
	clause(t4(A), true).
test(clause, A == a(a(),1)) :-
	clause(t5(A), true).

:- end_tests(zero_arity_compound).

:- begin_tests(term_singletons).

test(out, S == [Y]) :-
	term_singletons(X+X+Y,S).
test(out, S == Y) :-
	term_singletons(X+X+Y,[S]).
test(out, fail) :-
	term_singletons(X+X+_Y,[_,_]).
test(out, fail) :-
	term_singletons(X+X+_Y,[]).
test(out) :-
	term_singletons(X+X,[]).
test(out) :-
	term_singletons(zus,[]).

:- end_tests(term_singletons).
