Pytest Approxable Mixin
Example
from pytest_approxable import Approxable
from dataclasses import dataclass
from pytest import approx
@dataclass
class MetalProperties(Approxable):
name: str
heat_capacity: float
conductivity: float
def test_metal_equal():
mp1 = MetalProperties(name='metal1', heat_capacity=0.5, conductivity=1.)
mp2 = MetalProperties(name='metal2', heat_capacity=0.499999999, conductivity=0.9999999998)
assert approx(mp1.approxable_dict, abs=0.1) == mp2.approxable_dictProblem
When testing codes, we usually approximate floating numbers to avoid decimal points error. To do so, we use pytest.approx as follow
from pytest import approx
def test_approx():
a = 1.0000000000000001
b = 1.
assert approx(a, abs=0.1) == b # this will pass
assert a == b # this will failMoreover, we can also use this with the dictionary derived from a dataclass. For example,
from dataclasses import dataclass, asdict
from pytest import approx
@dataclass
class MetalProperties:
heat_capacity: float
conductivity: float
def test_metal_equal():
mp1 = MetalProperties(heat_capacity=0.5, conductivity=1.)
mp2 = MetalProperties(heat_capacity=0.499999999, conductivity=0.9999999998)
assert approx(asdict(mp1), abs=0.1) == asdict(mp2)Now the problem arises when we have non-number fields in the class
@dataclass
class MetalProperties:
name: str
heat_capacity: float
conductivity: float
def test_metal_equal():
mp1 = MetalProperties(name='metal1', heat_capacity=0.5, conductivity=1.)
mp2 = MetalProperties(name='metal2', heat_capacity=0.499999999, conductivity=0.9999999998)
assert approx(asdict(mp1), abs=0.1) == asdict(mp2)Above code will fails since attribute name can't be approximated
##Progress
- tests
- supports nested object
