Source code for priops.test.test_casting

"""Tests addition ``X() + Z()`` via ``Z -> Y``."""

import priops
from priops.test.classes import X, Y, Z
import nose.tools

def add_xy(x, y):
    """Adds an :class:`~priops.test.classes.X` instance and a
    :class:`~priops.test.classes.Y` instance."""

    return x.x + y.y

def cast_yz(z):
    """Casts a :class:`~priops.test.classes.Z` instance to a
    :class:`~priops.test.classes.Y` instance."""

    return Y(z.z)

p = priops.Priop()

edge_add_xy = priops.CallableEdge(
    input_node=priops.ClassNode(items=[X, Y]),
    output_node=priops.ClassNode(item=int),
    callable=add_xy, name='Add X + Y')
p.append(edge_add_xy)

edge_cast_yz = priops.CallableEdge(
    input_node=priops.ClassNode(item=Z),
    output_node=priops.ClassNode(item=Y),
    callable=cast_yz, name='Cast Z -> Y')
p.append(edge_cast_yz)

cpf = priops.ClassPathfinder(
    priop=p, output_node=priops.ClassNode(item=None), max_components=2,
    max_weight=2)

def test_succeeds():
    """Tests if ``X(1) + Z(3) == 4``."""

    nose.tools.eq_(cpf(X(1), Z(3)), 4)

def test_direct():
    """Tests if ``X(1) + Y(2) == 3`` still."""

    nose.tools.eq_(cpf(X(1), Y(2)), 3)

@nose.tools.raises(priops.NoPath)
def test_fails():
    """Tests that ``X(10)`` cannot be coerced with ``X(20)``."""

    cpf(X(10), X(20))