from sympy.core.logic import fuzzy_and
from sympy.core.sympify import _sympify
from sympy.multipledispatch import dispatch
from sympy.testing.pytest import XFAIL, raises
from sympy.assumptions.ask import Q
from sympy.core.add import Add
from sympy.core.basic import Basic
from sympy.core.expr import Expr
from sympy.core.function import Function
from sympy.core.mul import Mul
from sympy.core.numbers import (Float, I, Rational, nan, oo, pi, zoo)
from sympy.core.power import Pow
from sympy.core.singleton import S
from sympy.core.symbol import (Symbol, symbols)
from sympy.functions.elementary.exponential import (exp, exp_polar, log)
from sympy.functions.elementary.integers import (ceiling, floor)
from sympy.functions.elementary.miscellaneous import sqrt
from sympy.functions.elementary.trigonometric import (cos, sin)
from sympy.logic.boolalg import (And, Implies, Not, Or, Xor)
from sympy.sets import Reals
from sympy.simplify.simplify import simplify
from sympy.simplify.trigsimp import trigsimp
from sympy.core.relational import (Relational, Equality, Unequality,
                                   GreaterThan, LessThan, StrictGreaterThan,
                                   StrictLessThan, Rel, Eq, Lt, Le,
                                   Gt, Ge, Ne, is_le, is_gt, is_ge, is_lt, is_eq, is_neq)
from sympy.sets.sets import Interval, FiniteSet

from itertools import combinations

x, y, z, t = symbols('x,y,z,t')


def rel_check(a, b):
    from sympy.testing.pytest import raises
    assert a.is_number and b.is_number
    for do in range(len({type(a), type(b)})):
        if S.NaN in (a, b):
            v = [(a == b), (a != b)]
            assert len(set(v)) == 1 and v[0] == False
            assert not (a != b) and not (a == b)
            assert raises(TypeError, lambda: a < b)
            assert raises(TypeError, lambda: a <= b)
            assert raises(TypeError, lambda: a > b)
            assert raises(TypeError, lambda: a >= b)
        else:
            E = [(a == b), (a != b)]
            assert len(set(E)) == 2
            v = [
            (a < b), (a <= b), (a > b), (a >= b)]
            i = [
            [True,    True,     False,   False],
            [False,   True,     False,   True], # <-- i == 1
            [False,   False,    True,    True]].index(v)
            if i == 1:
                assert E[0] or (a.is_Float != b.is_Float) # ugh
            else:
                assert E[1]
        a, b = b, a
    return True


def test_rel_ne():
    assert Relational(x, y, '!=') == Ne(x, y)

    # issue 6116
    p = Symbol('p', positive=True)
    assert Ne(p, 0) is S.true


def test_rel_subs():
    e = Relational(x, y, '==')
    e = e.subs(x, z)

    assert isinstance(e, Equality)
    assert e.lhs == z
    assert e.rhs == y

    e = Relational(x, y, '>=')
    e = e.subs(x, z)

    assert isinstance(e, GreaterThan)
    assert e.lhs == z
    assert e.rhs == y

    e = Relational(x, y, '<=')
    e = e.subs(x, z)

    assert isinstance(e, LessThan)
    assert e.lhs == z
    assert e.rhs == y

    e = Relational(x, y, '>')
    e = e.subs(x, z)

    assert isinstance(e, StrictGreaterThan)
    assert e.lhs == z
    assert e.rhs == y

    e = Relational(x, y, '<')
    e = e.subs(x, z)

    assert isinstance(e, StrictLessThan)
    assert e.lhs == z
    assert e.rhs == y

    e = Eq(x, 0)
    assert e.subs(x, 0) is S.true
    assert e.subs(x, 1) is S.false


def test_wrappers():
    e = x + x**2

    res = Relational(y, e, '==')
    assert Rel(y, x + x**2, '==') == res
    assert Eq(y, x + x**2) == res

    res = Relational(y, e, '<')
    assert Lt(y, x + x**2) == res

    res = Relational(y, e, '<=')
    assert Le(y, x + x**2) == res

    res = Relational(y, e, '>')
    assert Gt(y, x + x**2) == res

    res = Relational(y, e, '>=')
    assert Ge(y, x + x**2) == res

    res = Relational(y, e, '!=')
    assert Ne(y, x + x**2) == res


def test_Eq_Ne():

    assert Eq(x, x)  # issue 5719

    # issue 6116
    p = Symbol('p', positive=True)
    assert Eq(p, 0) is S.false

    # issue 13348; 19048
    # SymPy is strict about 0 and 1 not being
    # interpreted as Booleans
    assert Eq(True, 1) is S.false
    assert Eq(False, 0) is S.false
    assert Eq(~x, 0) is S.false
    assert Eq(~x, 1) is S.false
    assert Ne(True, 1) is S.true
    assert Ne(False, 0) is S.true
    assert Ne(~x, 0) is S.true
    assert Ne(~x, 1) is S.true

    assert Eq((), 1) is S.false
    assert Ne((), 1) is S.true


def test_as_poly():
    from sympy.polys.polytools import Poly
    # Only Eq should have an as_poly method:
    assert Eq(x, 1).as_poly() == Poly(x - 1, x, domain='ZZ')
    raises(AttributeError, lambda: Ne(x, 1).as_poly())
    raises(AttributeError, lambda: Ge(x, 1).as_poly())
    raises(AttributeError, lambda: Gt(x, 1).as_poly())
    raises(AttributeError, lambda: Le(x, 1).as_poly())
    raises(AttributeError, lambda: Lt(x, 1).as_poly())


def test_rel_Infinity():
    # NOTE: All of these are actually handled by sympy.core.Number, and do
    # not create Relational objects.
    assert (oo > oo) is S.false
    assert (oo > -oo) is S.true
    assert (oo > 1) is S.true
    assert (oo < oo) is S.false
    assert (oo < -oo) is S.false
    assert (oo < 1) is S.false
    assert (oo >= oo) is S.true
    assert (oo >= -oo) is S.true
    assert (oo >= 1) is S.true
    assert (oo <= oo) is S.true
    assert (oo <= -oo) is S.false
    assert (oo <= 1) is S.false
    assert (-oo > oo) is S.false
    assert (-oo > -oo) is S.false
    assert (-oo > 1) is S.false
    assert (-oo < oo) is S.true
    assert (-oo < -oo) is S.false
    assert (-oo < 1) is S.true
    assert (-oo >= oo) is S.false
    assert (-oo >= -oo) is S.true
    assert (-oo >= 1) is S.false
    assert (-oo <= oo) is S.true
    assert (-oo <= -oo) is S.true
    assert (-oo <= 1) is S.true


def test_infinite_symbol_inequalities():
    x = Symbol('x', extended_positive=True, infinite=True)
    y = Symbol('y', extended_positive=True, infinite=True)
    z = Symbol('z', extended_negative=True, infinite=True)
    w = Symbol('w', extended_negative=True, infinite=True)

    inf_set = (x, y, oo)
    ninf_set = (z, w, -oo)

    for inf1 in inf_set:
        assert (inf1 < 1) is S.false
        assert (inf1 > 1) is S.true
        assert (inf1 <= 1) is S.false
        assert (inf1 >= 1) is S.true

        for inf2 in inf_set:
            assert (inf1 < inf2) is S.false
            assert (inf1 > inf2) is S.false
            assert (inf1 <= inf2) is S.true
            assert (inf1 >= inf2) is S.true

        for ninf1 in ninf_set:
            assert (inf1 < ninf1) is S.false
            assert (inf1 > ninf1) is S.true
            assert (inf1 <= ninf1) is S.false
            assert (inf1 >= ninf1) is S.true
            assert (ninf1 < inf1) is S.true
            assert (ninf1 > inf1) is S.false
            assert (ninf1 <= inf1) is S.true
            assert (ninf1 >= inf1) is S.false

    for ninf1 in ninf_set:
        assert (ninf1 < 1) is S.true
        assert (ninf1 > 1) is S.false
        assert (ninf1 <= 1) is S.true
        assert (ninf1 >= 1) is S.false

        for ninf2 in ninf_set:
            assert (ninf1 < ninf2) is S.false
            assert (ninf1 > ninf2) is S.false
            assert (ninf1 <= ninf2) is S.true
            assert (ninf1 >= ninf2) is S.true


def test_bool():
    assert Eq(0, 0) is S.true
    assert Eq(1, 0) is S.false
    assert Ne(0, 0) is S.false
    assert Ne(1, 0) is S.true
    assert Lt(0, 1) is S.true
    assert Lt(1, 0) is S.false
    assert Le(0, 1) is S.true
    assert Le(1, 0) is S.false
    assert Le(0, 0) is S.true
    assert Gt(1, 0) is S.true
    assert Gt(0, 1) is S.false
    assert Ge(1, 0) is S.true
    assert Ge(0, 1) is S.false
    assert Ge(1, 1) is S.true
    assert Eq(I, 2) is S.false
    assert Ne(I, 2) is S.true
    raises(TypeError, lambda: Gt(I, 2))
    raises(TypeError, lambda: Ge(I, 2))
    raises(TypeError, lambda: Lt(I, 2))
    raises(TypeError, lambda: Le(I, 2))
    a = Float('.000000000000000000001', '')
    b = Float('.0000000000000000000001', '')
    assert Eq(pi + a, pi + b) is S.false


def test_rich_cmp():
    assert (x < y) == Lt(x, y)
    assert (x <= y) == Le(x, y)
    assert (x > y) == Gt(x, y)
    assert (x >= y) == Ge(x, y)


def test_doit():
    from sympy.core.symbol import Symbol
    p = Symbol('p', positive=True)
    n = Symbol('n', negative=True)
    np = Symbol('np', nonpositive=True)
    nn = Symbol('nn', nonnegative=True)

    assert Gt(p, 0).doit() is S.true
    assert Gt(p, 1).doit() == Gt(p, 1)
    assert Ge(p, 0).doit() is S.true
    assert Le(p, 0).doit() is S.false
    assert Lt(n, 0).doit() is S.true
    assert Le(np, 0).doit() is S.true
    assert Gt(nn, 0).doit() == Gt(nn, 0)
    assert Lt(nn, 0).doit() is S.false

    assert Eq(x, 0).doit() == Eq(x, 0)


def test_new_relational():
    x = Symbol('x')

    assert Eq(x, 0) == Relational(x, 0)       # None ==> Equality
    assert Eq(x, 0) == Relational(x, 0, '==')
    assert Eq(x, 0) == Relational(x, 0, 'eq')
    assert Eq(x, 0) == Equality(x, 0)

    assert Eq(x, 0) != Relational(x, 1)       # None ==> Equality
    assert Eq(x, 0) != Relational(x, 1, '==')
    assert Eq(x, 0) != Relational(x, 1, 'eq')
    assert Eq(x, 0) != Equality(x, 1)

    assert Eq(x, -1) == Relational(x, -1)       # None ==> Equality
    assert Eq(x, -1) == Relational(x, -1, '==')
    assert Eq(x, -1) == Relational(x, -1, 'eq')
    assert Eq(x, -1) == Equality(x, -1)
    assert Eq(x, -1) != Relational(x, 1)       # None ==> Equality
    assert Eq(x, -1) != Relational(x, 1, '==')
    assert Eq(x, -1) != Relational(x, 1, 'eq')
    assert Eq(x, -1) != Equality(x, 1)

    assert Ne(x, 0) == Relational(x, 0, '!=')
    assert Ne(x, 0) == Relational(x, 0, '<>')
    assert Ne(x, 0) == Relational(x, 0, 'ne')
    assert Ne(x, 0) == Unequality(x, 0)
    assert Ne(x, 0) != Relational(x, 1, '!=')
    assert Ne(x, 0) != Relational(x, 1, '<>')
    assert Ne(x, 0) != Relational(x, 1, 'ne')
    assert Ne(x, 0) != Unequality(x, 1)

    assert Ge(x, 0) == Relational(x, 0, '>=')
    assert Ge(x, 0) == Relational(x, 0, 'ge')
    assert Ge(x, 0) == GreaterThan(x, 0)
    assert Ge(x, 1) != Relational(x, 0, '>=')
    assert Ge(x, 1) != Relational(x, 0, 'ge')
    assert Ge(x, 1) != GreaterThan(x, 0)
    assert (x >= 1) == Relational(x, 1, '>=')
    assert (x >= 1) == Relational(x, 1, 'ge')
    assert (x >= 1) == GreaterThan(x, 1)
    assert (x >= 0) != Relational(x, 1, '>=')
    assert (x >= 0) != Relational(x, 1, 'ge')
    assert (x >= 0) != GreaterThan(x, 1)

    assert Le(x, 0) == Relational(x, 0, '<=')
    assert Le(x, 0) == Relational(x, 0, 'le')
    assert Le(x, 0) == LessThan(x, 0)
    assert Le(x, 1) != Relational(x, 0, '<=')
    assert Le(x, 1) != Relational(x, 0, 'le')
    assert Le(x, 1) != LessThan(x, 0)
    assert (x <= 1) == Relational(x, 1, '<=')
    assert (x <= 1) == Relational(x, 1, 'le')
    assert (x <= 1) == LessThan(x, 1)
    assert (x <= 0) != Relational(x, 1, '<=')
    assert (x <= 0) != Relational(x, 1, 'le')
    assert (x <= 0) != LessThan(x, 1)

    assert Gt(x, 0) == Relational(x, 0, '>')
    assert Gt(x, 0) == Relational(x, 0, 'gt')
    assert Gt(x, 0) == StrictGreaterThan(x, 0)
    assert Gt(x, 1) != Relational(x, 0, '>')
    assert Gt(x, 1) != Relational(x, 0, 'gt')
    assert Gt(x, 1) != StrictGreaterThan(x, 0)
    assert (x > 1) == Relational(x, 1, '>')
    assert (x > 1) == Relational(x, 1, 'gt')
    assert (x > 1) == StrictGreaterThan(x, 1)
    assert (x > 0) != Relational(x, 1, '>')
    assert (x > 0) != Relational(x, 1, 'gt')
    assert (x > 0) != StrictGreaterThan(x, 1)

    assert Lt(x, 0) == Relational(x, 0, '<')
    assert Lt(x, 0) == Relational(x, 0, 'lt')
    assert Lt(x, 0) == StrictLessThan(x, 0)
    assert Lt(x, 1) != Relational(x, 0, '<')
    assert Lt(x, 1) != Relational(x, 0, 'lt')
    assert Lt(x, 1) != StrictLessThan(x, 0)
    assert (x < 1) == Relational(x, 1, '<')
    assert (x < 1) == Relational(x, 1, 'lt')
    assert (x < 1) == StrictLessThan(x, 1)
    assert (x < 0) != Relational(x, 1, '<')
    assert (x < 0) != Relational(x, 1, 'lt')
    assert (x < 0) != StrictLessThan(x, 1)

    # finally, some fuzz testing
    from sympy.core.random import randint
    for i in range(100):
        while 1:
            strtype, length = (chr, 65535) if randint(0, 1) else (chr, 255)
            relation_type = strtype(randint(0, length))
            if randint(0, 1):
                relation_type += strtype(randint(0, length))
            if relation_type not in ('==', 'eq', '!=', '<>', 'ne', '>=', 'ge',
                                     '<=', 'le', '>', 'gt', '<', 'lt', ':=',
                                     '+=', '-=', '*=', '/=', '%='):
                break

        raises(ValueError, lambda: Relational(x, 1, relation_type))
    assert all(Relational(x, 0, op).rel_op == '==' for op in ('eq', '=='))
    assert all(Relational(x, 0, op).rel_op == '!='
               for op in ('ne', '<>', '!='))
    assert all(Relational(x, 0, op).rel_op == '>' for op in ('gt', '>'))
    assert all(Relational(x, 0, op).rel_op == '<' for op in ('lt', '<'))
    assert all(Relational(x, 0, op).rel_op == '>=' for op in ('ge', '>='))
    assert all(Relational(x, 0, op).rel_op == '<=' for op in ('le', '<='))


def test_relational_arithmetic():
    for cls in [Eq, Ne, Le, Lt, Ge, Gt]:
        rel = cls(x, y)
        raises(TypeError, lambda: 0+rel)
        raises(TypeError, lambda: 1*rel)
        raises(TypeError, lambda: 1**rel)
        raises(TypeError, lambda: rel**1)
        raises(TypeError, lambda: Add(0, rel))
        raises(TypeError, lambda: Mul(1, rel))
        raises(TypeError, lambda: Pow(1, rel))
        raises(TypeError, lambda: Pow(rel, 1))


def test_relational_bool_output():
    # https://github.com/sympy/sympy/issues/5931
    raises(TypeError, lambda: bool(x > 3))
    raises(TypeError, lambda: bool(x >= 3))
    raises(TypeError, lambda: bool(x < 3))
    raises(TypeError, lambda: bool(x <= 3))
    raises(TypeError, lambda: bool(Eq(x, 3)))
    raises(TypeError, lambda: bool(Ne(x, 3)))


def test_relational_logic_symbols():
    # See issue 6204
    assert (x < y) & (z < t) == And(x < y, z < t)
    assert (x < y) | (z < t) == Or(x < y, z < t)
    assert ~(x < y) == Not(x < y)
    assert (x < y) >> (z < t) == Implies(x < y, z < t)
    assert (x < y) << (z < t) == Implies(z < t, x < y)
    assert (x < y) ^ (z < t) == Xor(x < y, z < t)

    assert isinstance((x < y) & (z < t), And)
    assert isinstance((x < y) | (z < t), Or)
    assert isinstance(~(x < y), GreaterThan)
    assert isinstance((x < y) >> (z < t), Implies)
    assert isinstance((x < y) << (z < t), Implies)
    assert isinstance((x < y) ^ (z < t), (Or, Xor))


def test_univariate_relational_as_set():
    assert (x > 0).as_set() == Interval(0, oo, True, True)
    assert (x >= 0).as_set() == Interval(0, oo)
    assert (x < 0).as_set() == Interval(-oo, 0, True, True)
    assert (x <= 0).as_set() == Interval(-oo, 0)
    assert Eq(x, 0).as_set() == FiniteSet(0)
    assert Ne(x, 0).as_set() == Interval(-oo, 0, True, True) + \
        Interval(0, oo, True, True)

    assert (x**2 >= 4).as_set() == Interval(-oo, -2) + Interval(2, oo)


@XFAIL
def test_multivariate_relational_as_set():
    assert (x*y >= 0).as_set() == Interval(0, oo)*Interval(0, oo) + \
        Interval(-oo, 0)*Interval(-oo, 0)


def test_Not():
    assert Not(Equality(x, y)) == Unequality(x, y)
    assert Not(Unequality(x, y)) == Equality(x, y)
    assert Not(StrictGreaterThan(x, y)) == LessThan(x, y)
    assert Not(StrictLessThan(x, y)) == GreaterThan(x, y)
    assert Not(GreaterThan(x, y)) == StrictLessThan(x, y)
    assert Not(LessThan(x, y)) == StrictGreaterThan(x, y)


def test_evaluate():
    assert str(Eq(x, x, evaluate=False)) == 'Eq(x, x)'
    assert Eq(x, x, evaluate=False).doit() == S.true
    assert str(Ne(x, x, evaluate=False)) == 'Ne(x, x)'
    assert Ne(x, x, evaluate=False).doit() == S.false

    assert str(Ge(x, x, evaluate=False)) == 'x >= x'
    assert str(Le(x, x, evaluate=False)) == 'x <= x'
    assert str(Gt(x, x, evaluate=False)) == 'x > x'
    assert str(Lt(x, x, evaluate=False)) == 'x < x'


def assert_all_ineq_raise_TypeError(a, b):
    raises(TypeError, lambda: a > b)
    raises(TypeError, lambda: a >= b)
    raises(TypeError, lambda: a < b)
    raises(TypeError, lambda: a <= b)
    raises(TypeError, lambda: b > a)
    raises(TypeError, lambda: b >= a)
    raises(TypeError, lambda: b < a)
    raises(TypeError, lambda: b <= a)


def assert_all_ineq_give_class_Inequality(a, b):
    """All inequality operations on `a` and `b` result in class Inequality."""
    from sympy.core.relational import _Inequality as Inequality
    assert isinstance(a > b,  Inequality)
    assert isinstance(a >= b, Inequality)
    assert isinstance(a < b,  Inequality)
    assert isinstance(a <= b, Inequality)
    assert isinstance(b > a,  Inequality)
    assert isinstance(b >= a, Inequality)
    assert isinstance(b < a,  Inequality)
    assert isinstance(b <= a, Inequality)


def test_imaginary_compare_raises_TypeError():
    # See issue #5724
    assert_all_ineq_raise_TypeError(I, x)


def test_complex_compare_not_real():
    # two cases which are not real
    y = Symbol('y', imaginary=True)
    z = Symbol('z', complex=True, extended_real=False)
    for w in (y, z):
        assert_all_ineq_raise_TypeError(2, w)
    # some cases which should remain un-evaluated
    t = Symbol('t')
    x = Symbol('x', real=True)
    z = Symbol('z', complex=True)
    for w in (x, z, t):
        assert_all_ineq_give_class_Inequality(2, w)


def test_imaginary_and_inf_compare_raises_TypeError():
    # See pull request #7835
    y = Symbol('y', imaginary=True)
    assert_all_ineq_raise_TypeError(oo, y)
    assert_all_ineq_raise_TypeError(-oo, y)


def test_complex_pure_imag_not_ordered():
    raises(TypeError, lambda: 2*I < 3*I)

    # more generally
    x = Symbol('x', real=True, nonzero=True)
    y = Symbol('y', imaginary=True)
    z = Symbol('z', complex=True)
    assert_all_ineq_raise_TypeError(I, y)

    t = I*x   # an imaginary number, should raise errors
    assert_all_ineq_raise_TypeError(2, t)

    t = -I*y   # a real number, so no errors
    assert_all_ineq_give_class_Inequality(2, t)

    t = I*z   # unknown, should be unevaluated
    assert_all_ineq_give_class_Inequality(2, t)


def test_x_minus_y_not_same_as_x_lt_y():
    """
    A consequence of pull request #7792 is that `x - y < 0` and `x < y`
    are not synonymous.
    """
    x = I + 2
    y = I + 3
    raises(TypeError, lambda: x < y)
    assert x - y < 0

    ineq = Lt(x, y, evaluate=False)
    raises(TypeError, lambda: ineq.doit())
    assert ineq.lhs - ineq.rhs < 0

    t = Symbol('t', imaginary=True)
    x = 2 + t
    y = 3 + t
    ineq = Lt(x, y, evaluate=False)
    raises(TypeError, lambda: ineq.doit())
    assert ineq.lhs - ineq.rhs < 0

    # this one should give error either way
    x = I + 2
    y = 2*I + 3
    raises(TypeError, lambda: x < y)
    raises(TypeError, lambda: x - y < 0)


def test_nan_equality_exceptions():
    # See issue #7774
    import random
    assert Equality(nan, nan) is S.false
    assert Unequality(nan, nan) is S.true

    # See issue #7773
    A = (x, S.Zero, S.One/3, pi, oo, -oo)
    assert Equality(nan, random.choice(A)) is S.false
    assert Equality(random.choice(A), nan) is S.false
    assert Unequality(nan, random.choice(A)) is S.true
    assert Unequality(random.choice(A), nan) is S.true


def test_nan_inequality_raise_errors():
    # See discussion in pull request #7776.  We test inequalities with
    # a set including examples of various classes.
    for q in (x, S.Zero, S(10), S.One/3, pi, S(1.3), oo, -oo, nan):
        assert_all_ineq_raise_TypeError(q, nan)


def test_nan_complex_inequalities():
    # Comparisons of NaN with non-real raise errors, we're not too
    # fussy whether its the NaN error or complex error.
    for r in (I, zoo, Symbol('z', imaginary=True)):
        assert_all_ineq_raise_TypeError(r, nan)


def test_complex_infinity_inequalities():
    raises(TypeError, lambda: zoo > 0)
    raises(TypeError, lambda: zoo >= 0)
    raises(TypeError, lambda: zoo < 0)
    raises(TypeError, lambda: zoo <= 0)


def test_inequalities_symbol_name_same():
    """Using the operator and functional forms should give same results."""
    # We test all combinations from a set
    # FIXME: could replace with random selection after test passes
    A = (x, y, S.Zero, S.One/3, pi, oo, -oo)
    for a in A:
        for b in A:
            assert Gt(a, b) == (a > b)
            assert Lt(a, b) == (a < b)
            assert Ge(a, b) == (a >= b)
            assert Le(a, b) == (a <= b)

    for b in (y, S.Zero, S.One/3, pi, oo, -oo):
        assert Gt(x, b, evaluate=False) == (x > b)
        assert Lt(x, b, evaluate=False) == (x < b)
        assert Ge(x, b, evaluate=False) == (x >= b)
        assert Le(x, b, evaluate=False) == (x <= b)

    for b in (y, S.Zero, S.One/3, pi, oo, -oo):
        assert Gt(b, x, evaluate=False) == (b > x)
        assert Lt(b, x, evaluate=False) == (b < x)
        assert Ge(b, x, evaluate=False) == (b >= x)
        assert Le(b, x, evaluate=False) == (b <= x)


def test_inequalities_symbol_name_same_complex():
    """Using the operator and functional forms should give same results.
    With complex non-real numbers, both should raise errors.
    """
    # FIXME: could replace with random selection after test passes
    for a in (x, S.Zero, S.One/3, pi, oo, Rational(1, 3)):
        raises(TypeError, lambda: Gt(a, I))
        raises(TypeError, lambda: a > I)
        raises(TypeError, lambda: Lt(a, I))
        raises(TypeError, lambda: a < I)
        raises(TypeError, lambda: Ge(a, I))
        raises(TypeError, lambda: a >= I)
        raises(TypeError, lambda: Le(a, I))
        raises(TypeError, lambda: a <= I)


def test_inequalities_cant_sympify_other():
    # see issue 7833
    from operator import gt, lt, ge, le

    bar = "foo"

    for a in (x, S.Zero, S.One/3, pi, I, zoo, oo, -oo, nan, Rational(1, 3)):
        for op in (lt, gt, le, ge):
            raises(TypeError, lambda: op(a, bar))


def test_ineq_avoid_wild_symbol_flip():
    # see issue #7951, we try to avoid this internally, e.g., by using
    # __lt__ instead of "<".
    from sympy.core.symbol import Wild
    p = symbols('p', cls=Wild)
    # x > p might flip, but Gt should not:
    assert Gt(x, p) == Gt(x, p, evaluate=False)
    # Previously failed as 'p > x':
    e = Lt(x, y).subs({y: p})
    assert e == Lt(x, p, evaluate=False)
    # Previously failed as 'p <= x':
    e = Ge(x, p).doit()
    assert e == Ge(x, p, evaluate=False)


def test_issue_8245():
    a = S("6506833320952669167898688709329/5070602400912917605986812821504")
    assert rel_check(a, a.n(10))
    assert rel_check(a, a.n(20))
    assert rel_check(a, a.n())
    # prec of 31 is enough to fully capture a as mpf
    assert Float(a, 31) == Float(str(a.p), '')/Float(str(a.q), '')
    for i in range(31):
        r = Rational(Float(a, i))
        f = Float(r)
        assert (f < a) == (Rational(f) < a)
    # test sign handling
    assert (-f < -a) == (Rational(-f) < -a)
    # test equivalence handling
    isa = Float(a.p,'')/Float(a.q,'')
    assert isa <= a
    assert not isa < a
    assert isa >= a
    assert not isa > a
    assert isa > 0

    a = sqrt(2)
    r = Rational(str(a.n(30)))
    assert rel_check(a, r)

    a = sqrt(2)
    r = Rational(str(a.n(29)))
    assert rel_check(a, r)

    assert Eq(log(cos(2)**2 + sin(2)**2), 0) is S.true


def test_issue_8449():
    p = Symbol('p', nonnegative=True)
    assert Lt(-oo, p)
    assert Ge(-oo, p) is S.false
    assert Gt(oo, -p)
    assert Le(oo, -p) is S.false


def test_simplify_relational():
    assert simplify(x*(y + 1) - x*y - x + 1 < x) == (x > 1)
    assert simplify(x*(y + 1) - x*y - x - 1 < x) == (x > -1)
    assert simplify(x < x*(y + 1) - x*y - x + 1) == (x < 1)
    q, r = symbols("q r")
    assert (((-q + r) - (q - r)) <= 0).simplify() == (q >= r)
    root2 = sqrt(2)
    equation = ((root2 * (-q + r) - root2 * (q - r)) <= 0).simplify()
    assert equation == (q >= r)
    r = S.One < x
    # canonical operations are not the same as simplification,
    # so if there is no simplification, canonicalization will
    # be done unless the measure forbids it
    assert simplify(r) == r.canonical
    assert simplify(r, ratio=0) != r.canonical
    # this is not a random test; in _eval_simplify
    # this will simplify to S.false and that is the
    # reason for the 'if r.is_Relational' in Relational's
    # _eval_simplify routine
    assert simplify(-(2**(pi*Rational(3, 2)) + 6**pi)**(1/pi) +
                    2*(2**(pi/2) + 3**pi)**(1/pi) < 0) is S.false
    # canonical at least
    assert Eq(y, x).simplify() == Eq(x, y)
    assert Eq(x - 1, 0).simplify() == Eq(x, 1)
    assert Eq(x - 1, x).simplify() == S.false
    assert Eq(2*x - 1, x).simplify() == Eq(x, 1)
    assert Eq(2*x, 4).simplify() == Eq(x, 2)
    z = cos(1)**2 + sin(1)**2 - 1  # z.is_zero is None
    assert Eq(z*x, 0).simplify() == S.true

    assert Ne(y, x).simplify() == Ne(x, y)
    assert Ne(x - 1, 0).simplify() == Ne(x, 1)
    assert Ne(x - 1, x).simplify() == S.true
    assert Ne(2*x - 1, x).simplify() == Ne(x, 1)
    assert Ne(2*x, 4).simplify() == Ne(x, 2)
    assert Ne(z*x, 0).simplify() == S.false

    # No real-valued assumptions
    assert Ge(y, x).simplify() == Le(x, y)
    assert Ge(x - 1, 0).simplify() == Ge(x, 1)
    assert Ge(x - 1, x).simplify() == S.false
    assert Ge(2*x - 1, x).simplify() == Ge(x, 1)
    assert Ge(2*x, 4).simplify() == Ge(x, 2)
    assert Ge(z*x, 0).simplify() == S.true
    assert Ge(x, -2).simplify() == Ge(x, -2)
    assert Ge(-x, -2).simplify() == Le(x, 2)
    assert Ge(x, 2).simplify() == Ge(x, 2)
    assert Ge(-x, 2).simplify() == Le(x, -2)

    assert Le(y, x).simplify() == Ge(x, y)
    assert Le(x - 1, 0).simplify() == Le(x, 1)
    assert Le(x - 1, x).simplify() == S.true
    assert Le(2*x - 1, x).simplify() == Le(x, 1)
    assert Le(2*x, 4).simplify() == Le(x, 2)
    assert Le(z*x, 0).simplify() == S.true
    assert Le(x, -2).simplify() == Le(x, -2)
    assert Le(-x, -2).simplify() == Ge(x, 2)
    assert Le(x, 2).simplify() == Le(x, 2)
    assert Le(-x, 2).simplify() == Ge(x, -2)

    assert Gt(y, x).simplify() == Lt(x, y)
    assert Gt(x - 1, 0).simplify() == Gt(x, 1)
    assert Gt(x - 1, x).simplify() == S.false
    assert Gt(2*x - 1, x).simplify() == Gt(x, 1)
    assert Gt(2*x, 4).simplify() == Gt(x, 2)
    assert Gt(z*x, 0).simplify() == S.false
    assert Gt(x, -2).simplify() == Gt(x, -2)
    assert Gt(-x, -2).simplify() == Lt(x, 2)
    assert Gt(x, 2).simplify() == Gt(x, 2)
    assert Gt(-x, 2).simplify() == Lt(x, -2)

    assert Lt(y, x).simplify() == Gt(x, y)
    assert Lt(x - 1, 0).simplify() == Lt(x, 1)
    assert Lt(x - 1, x).simplify() == S.true
    assert Lt(2*x - 1, x).simplify() == Lt(x, 1)
    assert Lt(2*x, 4).simplify() == Lt(x, 2)
    assert Lt(z*x, 0).simplify() == S.false
    assert Lt(x, -2).simplify() == Lt(x, -2)
    assert Lt(-x, -2).simplify() == Gt(x, 2)
    assert Lt(x, 2).simplify() == Lt(x, 2)
    assert Lt(-x, 2).simplify() == Gt(x, -2)

    # Test particulat branches of _eval_simplify
    m = exp(1) - exp_polar(1)
    assert simplify(m*x > 1) is S.false
    # These two tests the same branch
    assert simplify(m*x + 2*m*y > 1) is S.false
    assert simplify(m*x + y > 1 + y) is S.false


def test_equals():
    w, x, y, z = symbols('w:z')
    f = Function('f')
    assert Eq(x, 1).equals(Eq(x*(y + 1) - x*y - x + 1, x))
    assert Eq(x, y).equals(x < y, True) == False
    assert Eq(x, f(1)).equals(Eq(x, f(2)), True) == f(1) - f(2)
    assert Eq(f(1), y).equals(Eq(f(2), y), True) == f(1) - f(2)
    assert Eq(x, f(1)).equals(Eq(f(2), x), True) == f(1) - f(2)
    assert Eq(f(1), x).equals(Eq(x, f(2)), True) == f(1) - f(2)
    assert Eq(w, x).equals(Eq(y, z), True) == False
    assert Eq(f(1), f(2)).equals(Eq(f(3), f(4)), True) == f(1) - f(3)
    assert (x < y).equals(y > x, True) == True
    assert (x < y).equals(y >= x, True) == False
    assert (x < y).equals(z < y, True) == False
    assert (x < y).equals(x < z, True) == False
    assert (x < f(1)).equals(x < f(2), True) == f(1) - f(2)
    assert (f(1) < x).equals(f(2) < x, True) == f(1) - f(2)


def test_reversed():
    assert (x < y).reversed == (y > x)
    assert (x <= y).reversed == (y >= x)
    assert Eq(x, y, evaluate=False).reversed == Eq(y, x, evaluate=False)
    assert Ne(x, y, evaluate=False).reversed == Ne(y, x, evaluate=False)
    assert (x >= y).reversed == (y <= x)
    assert (x > y).reversed == (y < x)


def test_canonical():
    c = [i.canonical for i in (
        x + y < z,
        x + 2 > 3,
        x < 2,
        S(2) > x,
        x**2 > -x/y,
        Gt(3, 2, evaluate=False)
        )]
    assert [i.canonical for i in c] == c
    assert [i.reversed.canonical for i in c] == c
    assert not any(i.lhs.is_Number and not i.rhs.is_Number for i in c)

    c = [i.reversed.func(i.rhs, i.lhs, evaluate=False).canonical for i in c]
    assert [i.canonical for i in c] == c
    assert [i.reversed.canonical for i in c] == c
    assert not any(i.lhs.is_Number and not i.rhs.is_Number for i in c)
    assert Eq(y < x, x > y).canonical is S.true


@XFAIL
def test_issue_8444_nonworkingtests():
    x = symbols('x', real=True)
    assert (x <= oo) == (x >= -oo) == True

    x = symbols('x')
    assert x >= floor(x)
    assert (x < floor(x)) == False
    assert x <= ceiling(x)
    assert (x > ceiling(x)) == False


def test_issue_8444_workingtests():
    x = symbols('x')
    assert Gt(x, floor(x)) == Gt(x, floor(x), evaluate=False)
    assert Ge(x, floor(x)) == Ge(x, floor(x), evaluate=False)
    assert Lt(x, ceiling(x)) == Lt(x, ceiling(x), evaluate=False)
    assert Le(x, ceiling(x)) == Le(x, ceiling(x), evaluate=False)
    i = symbols('i', integer=True)
    assert (i > floor(i)) == False
    assert (i < ceiling(i)) == False


def test_issue_10304():
    d = cos(1)**2 + sin(1)**2 - 1
    assert d.is_comparable is False  # if this fails, find a new d
    e = 1 + d*I
    assert simplify(Eq(e, 0)) is S.false


def test_issue_18412():
    d = (Rational(1, 6) + z / 4 / y)
    assert Eq(x, pi * y**3 * d).replace(y**3, z) == Eq(x, pi * z * d)


def test_issue_10401():
    x = symbols('x')
    fin = symbols('inf', finite=True)
    inf = symbols('inf', infinite=True)
    inf2 = symbols('inf2', infinite=True)
    infx = symbols('infx', infinite=True, extended_real=True)
    # Used in the commented tests below:
    #infx2 = symbols('infx2', infinite=True, extended_real=True)
    infnx = symbols('inf~x', infinite=True, extended_real=False)
    infnx2 = symbols('inf~x2', infinite=True, extended_real=False)
    infp = symbols('infp', infinite=True, extended_positive=True)
    infp1 = symbols('infp1', infinite=True, extended_positive=True)
    infn = symbols('infn', infinite=True, extended_negative=True)
    zero = symbols('z', zero=True)
    nonzero = symbols('nz', zero=False, finite=True)

    assert Eq(1/(1/x + 1), 1).func is Eq
    assert Eq(1/(1/x + 1), 1).subs(x, S.ComplexInfinity) is S.true
    assert Eq(1/(1/fin + 1), 1) is S.false

    T, F = S.true, S.false
    assert Eq(fin, inf) is F
    assert Eq(inf, inf2) not in (T, F) and inf != inf2
    assert Eq(1 + inf, 2 + inf2) not in (T, F) and inf != inf2
    assert Eq(infp, infp1) is T
    assert Eq(infp, infn) is F
    assert Eq(1 + I*oo, I*oo) is F
    assert Eq(I*oo, 1 + I*oo) is F
    assert Eq(1 + I*oo, 2 + I*oo) is F
    assert Eq(1 + I*oo, 2 + I*infx) is F
    assert Eq(1 + I*oo, 2 + infx) is F
    # FIXME: The test below fails because (-infx).is_extended_positive is True
    # (should be None)
    #assert Eq(1 + I*infx, 1 + I*infx2) not in (T, F) and infx != infx2
    #
    assert Eq(zoo, sqrt(2) + I*oo) is F
    assert Eq(zoo, oo) is F
    r = Symbol('r', real=True)
    i = Symbol('i', imaginary=True)
    assert Eq(i*I, r) not in (T, F)
    assert Eq(infx, infnx) is F
    assert Eq(infnx, infnx2) not in (T, F) and infnx != infnx2
    assert Eq(zoo, oo) is F
    assert Eq(inf/inf2, 0) is F
    assert Eq(inf/fin, 0) is F
    assert Eq(fin/inf, 0) is T
    assert Eq(zero/nonzero, 0) is T and ((zero/nonzero) != 0)
    # The commented out test below is incorrect because:
    assert zoo == -zoo
    assert Eq(zoo, -zoo) is T
    assert Eq(oo, -oo) is F
    assert Eq(inf, -inf) not in (T, F)

    assert Eq(fin/(fin + 1), 1) is S.false

    o = symbols('o', odd=True)
    assert Eq(o, 2*o) is S.false

    p = symbols('p', positive=True)
    assert Eq(p/(p - 1), 1) is F


def test_issue_10633():
    assert Eq(True, False) == False
    assert Eq(False, True) == False
    assert Eq(True, True) == True
    assert Eq(False, False) == True


def test_issue_10927():
    x = symbols('x')
    assert str(Eq(x, oo)) == 'Eq(x, oo)'
    assert str(Eq(x, -oo)) == 'Eq(x, -oo)'


def test_issues_13081_12583_12534():
    # 13081
    r = Rational('905502432259640373/288230376151711744')
    assert (r < pi) is S.false
    assert (r > pi) is S.true
    # 12583
    v = sqrt(2)
    u = sqrt(v) + 2/sqrt(10 - 8/sqrt(2 - v) + 4*v*(1/sqrt(2 - v) - 1))
    assert (u >= 0) is S.true
    # 12534; Rational vs NumberSymbol
    # here are some precisions for which Rational forms
    # at a lower and higher precision bracket the value of pi
    # e.g. for p = 20:
    # Rational(pi.n(p + 1)).n(25) = 3.14159265358979323846 2834
    #                    pi.n(25) = 3.14159265358979323846 2643
    # Rational(pi.n(p    )).n(25) = 3.14159265358979323846 1987
    assert [p for p in range(20, 50) if
            (Rational(pi.n(p)) < pi) and
            (pi < Rational(pi.n(p + 1)))] == [20, 24, 27, 33, 37, 43, 48]
    # pick one such precision and affirm that the reversed operation
    # gives the opposite result, i.e. if x < y is true then x > y
    # must be false
    for i in (20, 21):
        v = pi.n(i)
        assert rel_check(Rational(v), pi)
        assert rel_check(v, pi)
    assert rel_check(pi.n(20), pi.n(21))
    # Float vs Rational
    # the rational form is less than the floating representation
    # at the same precision
    assert [i for i in range(15, 50) if Rational(pi.n(i)) > pi.n(i)] == []
    # this should be the same if we reverse the relational
    assert [i for i in range(15, 50) if pi.n(i) < Rational(pi.n(i))] == []

def test_issue_18188():
    from sympy.sets.conditionset import ConditionSet
    result1 = Eq(x*cos(x) - 3*sin(x), 0)
    assert result1.as_set() == ConditionSet(x, Eq(x*cos(x) - 3*sin(x), 0), Reals)

    result2 = Eq(x**2 + sqrt(x*2) + sin(x), 0)
    assert result2.as_set() == ConditionSet(x, Eq(sqrt(2)*sqrt(x) + x**2 + sin(x), 0), Reals)

def test_binary_symbols():
    ans = {x}
    for f in Eq, Ne:
        for t in S.true, S.false:
            eq = f(x, S.true)
            assert eq.binary_symbols == ans
            assert eq.reversed.binary_symbols == ans
        assert f(x, 1).binary_symbols == set()


def test_rel_args():
    # can't have Boolean args; this is automatic for True/False
    # with Python 3 and we confirm that SymPy does the same
    # for true/false
    for op in ['<', '<=', '>', '>=']:
        for b in (S.true, x < 1, And(x, y)):
            for v in (0.1, 1, 2**32, t, S.One):
                raises(TypeError, lambda: Relational(b, v, op))


def test_Equality_rewrite_as_Add():
    eq = Eq(x + y, y - x)
    assert eq.rewrite(Add) == 2*x
    assert eq.rewrite(Add, evaluate=None).args == (x, x, y, -y)
    assert eq.rewrite(Add, evaluate=False).args == (x, y, x, -y)
    for e in (True, False, None):
        assert Eq(x, 0, evaluate=e).rewrite(Add) == x
        assert Eq(0, x, evaluate=e).rewrite(Add) == x


def test_issue_15847():
    a = Ne(x*(x+y), x**2 + x*y)
    assert simplify(a) == False


def test_negated_property():
    eq = Eq(x, y)
    assert eq.negated == Ne(x, y)

    eq = Ne(x, y)
    assert eq.negated == Eq(x, y)

    eq = Ge(x + y, y - x)
    assert eq.negated == Lt(x + y, y - x)

    for f in (Eq, Ne, Ge, Gt, Le, Lt):
        assert f(x, y).negated.negated == f(x, y)


def test_reversedsign_property():
    eq = Eq(x, y)
    assert eq.reversedsign == Eq(-x, -y)

    eq = Ne(x, y)
    assert eq.reversedsign == Ne(-x, -y)

    eq = Ge(x + y, y - x)
    assert eq.reversedsign == Le(-x - y, x - y)

    for f in (Eq, Ne, Ge, Gt, Le, Lt):
        assert f(x, y).reversedsign.reversedsign == f(x, y)

    for f in (Eq, Ne, Ge, Gt, Le, Lt):
        assert f(-x, y).reversedsign.reversedsign == f(-x, y)

    for f in (Eq, Ne, Ge, Gt, Le, Lt):
        assert f(x, -y).reversedsign.reversedsign == f(x, -y)

    for f in (Eq, Ne, Ge, Gt, Le, Lt):
        assert f(-x, -y).reversedsign.reversedsign == f(-x, -y)


def test_reversed_reversedsign_property():
    for f in (Eq, Ne, Ge, Gt, Le, Lt):
        assert f(x, y).reversed.reversedsign == f(x, y).reversedsign.reversed

    for f in (Eq, Ne, Ge, Gt, Le, Lt):
        assert f(-x, y).reversed.reversedsign == f(-x, y).reversedsign.reversed

    for f in (Eq, Ne, Ge, Gt, Le, Lt):
        assert f(x, -y).reversed.reversedsign == f(x, -y).reversedsign.reversed

    for f in (Eq, Ne, Ge, Gt, Le, Lt):
        assert f(-x, -y).reversed.reversedsign == \
            f(-x, -y).reversedsign.reversed


def test_improved_canonical():
    def test_different_forms(listofforms):
        for form1, form2 in combinations(listofforms, 2):
            assert form1.canonical == form2.canonical

    def generate_forms(expr):
        return [expr, expr.reversed, expr.reversedsign,
                expr.reversed.reversedsign]

    test_different_forms(generate_forms(x > -y))
    test_different_forms(generate_forms(x >= -y))
    test_different_forms(generate_forms(Eq(x, -y)))
    test_different_forms(generate_forms(Ne(x, -y)))
    test_different_forms(generate_forms(pi < x))
    test_different_forms(generate_forms(pi - 5*y < -x + 2*y**2 - 7))

    assert (pi >= x).canonical == (x <= pi)


def test_set_equality_canonical():
    a, b, c = symbols('a b c')

    A = Eq(FiniteSet(a, b, c), FiniteSet(1, 2, 3))
    B = Ne(FiniteSet(a, b, c), FiniteSet(4, 5, 6))

    assert A.canonical == A.reversed
    assert B.canonical == B.reversed


def test_trigsimp():
    # issue 16736
    s, c = sin(2*x), cos(2*x)
    eq = Eq(s, c)
    assert trigsimp(eq) == eq  # no rearrangement of sides
    # simplification of sides might result in
    # an unevaluated Eq
    changed = trigsimp(Eq(s + c, sqrt(2)))
    assert isinstance(changed, Eq)
    assert changed.subs(x, pi/8) is S.true
    # or an evaluated one
    assert trigsimp(Eq(cos(x)**2 + sin(x)**2, 1)) is S.true


def test_polynomial_relation_simplification():
    assert Ge(3*x*(x + 1) + 4, 3*x).simplify() in [Ge(x**2, -Rational(4,3)), Le(-x**2, Rational(4, 3))]
    assert Le(-(3*x*(x + 1) + 4), -3*x).simplify() in [Ge(x**2, -Rational(4,3)), Le(-x**2, Rational(4, 3))]
    assert ((x**2+3)*(x**2-1)+3*x >= 2*x**2).simplify() in [(x**4 + 3*x >= 3), (-x**4 - 3*x <= -3)]


def test_multivariate_linear_function_simplification():
    assert Ge(x + y, x - y).simplify() == Ge(y, 0)
    assert Le(-x + y, -x - y).simplify() == Le(y, 0)
    assert Eq(2*x + y, 2*x + y - 3).simplify() == False
    assert (2*x + y > 2*x + y - 3).simplify() == True
    assert (2*x + y < 2*x + y - 3).simplify() == False
    assert (2*x + y < 2*x + y + 3).simplify() == True
    a, b, c, d, e, f, g = symbols('a b c d e f g')
    assert Lt(a + b + c + 2*d, 3*d - f + g). simplify() == Lt(a, -b - c + d - f + g)


def test_nonpolymonial_relations():
    assert Eq(cos(x), 0).simplify() == Eq(cos(x), 0)

def test_18778():
    raises(TypeError, lambda: is_le(Basic(), Basic()))
    raises(TypeError, lambda: is_gt(Basic(), Basic()))
    raises(TypeError, lambda: is_ge(Basic(), Basic()))
    raises(TypeError, lambda: is_lt(Basic(), Basic()))

def test_EvalEq():
    """

    This test exists to ensure backwards compatibility.
    The method to use is _eval_is_eq
    """
    from sympy.core.expr import Expr

    class PowTest(Expr):
        def __new__(cls, base, exp):
           return Basic.__new__(PowTest, _sympify(base), _sympify(exp))

        def _eval_Eq(lhs, rhs):
            if type(lhs) == PowTest and type(rhs) == PowTest:
                return lhs.args[0] == rhs.args[0] and lhs.args[1] == rhs.args[1]

    assert is_eq(PowTest(3, 4), PowTest(3,4))
    assert is_eq(PowTest(3, 4), _sympify(4)) is None
    assert is_neq(PowTest(3, 4), PowTest(3,7))


def test_is_eq():
    # test assumptions
    assert is_eq(x, y, Q.infinite(x) & Q.finite(y)) is False
    assert is_eq(x, y, Q.infinite(x) & Q.infinite(y) & Q.extended_real(x) & ~Q.extended_real(y)) is False
    assert is_eq(x, y, Q.infinite(x) & Q.infinite(y) & Q.extended_positive(x) & Q.extended_negative(y)) is False

    assert is_eq(x+I, y+I, Q.infinite(x) & Q.finite(y)) is False
    assert is_eq(1+x*I, 1+y*I, Q.infinite(x) & Q.finite(y)) is False

    assert is_eq(x, S(0), assumptions=Q.zero(x))
    assert is_eq(x, S(0), assumptions=~Q.zero(x)) is False
    assert is_eq(x, S(0), assumptions=Q.nonzero(x)) is False
    assert is_neq(x, S(0), assumptions=Q.zero(x)) is False
    assert is_neq(x, S(0), assumptions=~Q.zero(x))
    assert is_neq(x, S(0), assumptions=Q.nonzero(x))

    # test registration
    class PowTest(Expr):
        def __new__(cls, base, exp):
            return Basic.__new__(cls, _sympify(base), _sympify(exp))

    @dispatch(PowTest, PowTest)
    def _eval_is_eq(lhs, rhs):
        if type(lhs) == PowTest and type(rhs) == PowTest:
            return fuzzy_and([is_eq(lhs.args[0], rhs.args[0]), is_eq(lhs.args[1], rhs.args[1])])

    assert is_eq(PowTest(3, 4), PowTest(3,4))
    assert is_eq(PowTest(3, 4), _sympify(4)) is None
    assert is_neq(PowTest(3, 4), PowTest(3,7))


def test_is_ge_le():
    # test assumptions
    assert is_ge(x, S(0), Q.nonnegative(x)) is True
    assert is_ge(x, S(0), Q.negative(x)) is False

    # test registration
    class PowTest(Expr):
        def __new__(cls, base, exp):
            return Basic.__new__(cls, _sympify(base), _sympify(exp))

    @dispatch(PowTest, PowTest)
    def _eval_is_ge(lhs, rhs):
        if type(lhs) == PowTest and type(rhs) == PowTest:
            return fuzzy_and([is_ge(lhs.args[0], rhs.args[0]), is_ge(lhs.args[1], rhs.args[1])])

    assert is_ge(PowTest(3, 9), PowTest(3,2))
    assert is_gt(PowTest(3, 9), PowTest(3,2))
    assert is_le(PowTest(3, 2), PowTest(3,9))
    assert is_lt(PowTest(3, 2), PowTest(3,9))


def test_weak_strict():
    for func in (Eq, Ne):
        eq = func(x, 1)
        assert eq.strict == eq.weak == eq
    eq = Gt(x, 1)
    assert eq.weak == Ge(x, 1)
    assert eq.strict == eq
    eq = Lt(x, 1)
    assert eq.weak == Le(x, 1)
    assert eq.strict == eq
    eq = Ge(x, 1)
    assert eq.strict == Gt(x, 1)
    assert eq.weak == eq
    eq = Le(x, 1)
    assert eq.strict == Lt(x, 1)
    assert eq.weak == eq