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ljkiwi/kiwi/py/tests/test_variable.py

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4.3 KiB
Python

# --------------------------------------------------------------------------------------
# Copyright (c) 2014-2022, Nucleic Development Team.
#
# Distributed under the terms of the Modified BSD License.
#
# The full license is in the file LICENSE, distributed with this software.
# --------------------------------------------------------------------------------------
import math
import operator
import sys
import pytest
from kiwisolver import Constraint, Expression, Term, Variable, strength
def test_variable_methods() -> None:
"""Test the variable modification methods."""
v = Variable()
assert v.name() == ""
v.setName("Δ")
assert v.name() == "Δ"
v.setName("foo")
assert v.name() == "foo"
with pytest.raises(TypeError):
v.setName(1) # type: ignore
if sys.version_info >= (3,):
with pytest.raises(TypeError):
v.setName(b"r") # type: ignore
assert v.value() == 0.0
assert v.context() is None
ctx = object()
v.setContext(ctx)
assert v.context() is ctx
assert str(v) == "foo"
with pytest.raises(TypeError):
Variable(1) # type: ignore
def test_variable_neg() -> None:
"""Test neg on a variable."""
v = Variable("foo")
neg = -v
assert isinstance(neg, Term)
assert neg.variable() is v and neg.coefficient() == -1
def test_variable_mul() -> None:
"""Test variable multiplications."""
v = Variable("foo")
v2 = Variable("bar")
for mul in (v * 2.0, 2 * v):
assert isinstance(mul, Term)
assert mul.variable() is v and mul.coefficient() == 2
with pytest.raises(TypeError):
v * v2 # type: ignore
def test_variable_division() -> None:
"""Test variable divisions."""
v = Variable("foo")
v2 = Variable("bar")
div = v / 2.0
assert isinstance(div, Term)
assert div.variable() is v and div.coefficient() == 0.5
with pytest.raises(TypeError):
v / v2 # type: ignore
with pytest.raises(ZeroDivisionError):
v / 0
def test_variable_addition() -> None:
"""Test variable additions."""
v = Variable("foo")
v2 = Variable("bar")
for add in (v + 2, 2.0 + v):
assert isinstance(add, Expression)
assert add.constant() == 2
terms = add.terms()
assert (
len(terms) == 1 and terms[0].variable() is v and terms[0].coefficient() == 1
)
add2 = v + v2
assert isinstance(add2, Expression)
assert add2.constant() == 0
terms = add2.terms()
assert (
len(terms) == 2
and terms[0].variable() is v
and terms[0].coefficient() == 1
and terms[1].variable() is v2
and terms[1].coefficient() == 1
)
with pytest.raises(TypeError):
v + "" # type: ignore
def test_variable_sub() -> None:
"""Test variable substractions."""
v = Variable("foo")
v2 = Variable("bar")
for sub, diff in zip((v - 2, 2 - v), (-2, 2)):
assert isinstance(sub, Expression)
assert sub.constant() == diff
terms = sub.terms()
assert (
len(terms) == 1
and terms[0].variable() is v
and terms[0].coefficient() == -math.copysign(1, diff)
)
sub2 = v - v2
assert isinstance(sub2, Expression)
assert sub2.constant() == 0
terms = sub2.terms()
assert (
len(terms) == 2
and terms[0].variable() is v
and terms[0].coefficient() == 1
and terms[1].variable() is v2
and terms[1].coefficient() == -1
)
def test_variable_rich_compare_operations() -> None:
"""Test using comparison on variables."""
v = Variable("foo")
v2 = Variable("Δ")
for op, symbol in ((operator.le, "<="), (operator.eq, "=="), (operator.ge, ">=")):
c = op(v, v2 + 1)
assert isinstance(c, Constraint)
e = c.expression()
t = e.terms()
assert len(t) == 2
if t[0].variable() is not v:
t = (t[1], t[0])
assert (
t[0].variable() is v
and t[0].coefficient() == 1
and t[1].variable() is v2
and t[1].coefficient() == -1
)
assert e.constant() == -1
assert c.op() == symbol and c.strength() == strength.required
for op in (operator.lt, operator.ne, operator.gt):
with pytest.raises(TypeError):
op(v, v2)