test_modello.py

"""Functional tests for Modello instances."""
from modello import BoundInstanceDummy, InstanceDummy, Modello
from sympy import simplify


def test_no_constraints():
    """A model with no constraints just has dummy attributes."""

    class ExampleClass(Modello):
        thing = InstanceDummy("thing")

    instance = ExampleClass("Example")
    assert isinstance(instance.thing, BoundInstanceDummy)

    instance = ExampleClass("Example", thing=1)
    expected = simplify(1)
    assert isinstance(instance.thing, type(expected))
    assert instance.thing == expected


def test_multiple_inheritance_expr_conflict():
    """Overrided modello attributes are replaced with new values."""

    class ExampleA(Modello):
        conflicted = InstanceDummy("conflicted")
        a = conflicted

    class ExampleB(Modello):
        conflicted = InstanceDummy("conflicted")
        b = conflicted

    class ExampleC(ExampleA, ExampleB):
        pass

    instance = ExampleC("Example")
    assert instance.a == instance.b  # dummy is different but value is the same
    assert instance.a == instance.conflicted

    assert ExampleC.conflicted == ExampleB.conflicted
    assert ExampleC.conflicted != ExampleA.conflicted