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#!/usr/bin/env python3
"""graphviz.(Di)graph instance transformation: LazyGraph and LazyDigraph."""
import functools
from unittest import mock
import graphviz
WRAPS = ['Graph', 'Digraph']
RENDERING_METHODS = ('pipe', 'save', 'render', 'view', 'unflatten')
INPUT_PROPERTIES = ('source',)
__all__ = ['LazyGraph', 'LazyDigraph']
def lazy_graph_cls(wrapped_cls_name: str):
return functools.partial(create_lazy_graph_instance, wrapped_cls_name)
def create_lazy_graph_instance(cls_name: str,
*init_args,
**init_kwargs) -> mock.NonCallableMagicMock:
cls = getattr(graphviz, cls_name)
if cls not in (graphviz.Graph, graphviz.Digraph):
raise ValueError(f'cls_name: {cls_name!r}')
fake = mock.create_autospec(cls, instance=True, spec_set=True)
fake.copy.side_effect = NotImplementedError # TODO
def make_real_inst(calls):
dot = cls(*init_args, **init_kwargs)
for method_name, args, kwargs in calls:
method = getattr(dot, method_name)
method(*args, **kwargs) # ignore return value
return dot
def make_methodcaller(method_name):
def call_method(*args, **kwargs):
last_call = fake.mock_calls.pop()
assert last_call == getattr(mock.call, method_name)(*args, **kwargs)
dot = make_real_inst(fake.mock_calls)
method = getattr(dot, method_name)
return method(*args, **kwargs)
return call_method
for method_name in RENDERING_METHODS:
getattr(fake, method_name).side_effect = make_methodcaller(method_name)
def make_property(property_name):
def property_func(*args):
last_call = property_mock.mock_calls.pop()
assert last_call == mock.call(*args)
assert not property_mock.mock_calls
dot = make_real_inst(fake.mock_calls)
property_obj = getattr(dot.__class__, property_name)
property_func = property_obj.fset if args else property_obj.fget
return property_func(dot, *args)
property_mock = mock.PropertyMock(side_effect=property_func)
return property_mock
for property_name in INPUT_PROPERTIES:
setattr(type(fake), property_name, make_property(property_name))
return fake
LazyGraph, LazyDigraph = map(lazy_graph_cls, WRAPS)
if __name__ == '__main__':
dot = LazyDigraph(filename='round-table.gv', comment='The Round Table')
dot.node('A', 'King Arthur')
dot.node('B', 'Sir Bedevere the Wise')
dot.node('L', 'Sir Lancelot the Brave')
dot.edges(['AB', 'AL'])
dot.edge('B', 'L', constraint='false')
print(repr(dot), dot.mock_calls, dot.source, sep='\n')
#dot.view() # noqa: E265
def transform(mock_calls):
"""Replace full name labels with first names."""
for call in mock_calls:
method_name, args, kwargs = call
if method_name == 'node':
name, label = args
label = label.split()[1]
yield mock.call.node(name, label, **kwargs)
else:
yield call
dot.mock_calls = list(transform(dot.mock_calls))
# reverse the Bedvedere -> Lancelot edge
method_name, tail_head, edge_attrs = dot.mock_calls.pop()
assert method_name == 'edge'
dot.edge(*reversed(tail_head), **edge_attrs)
print(repr(dot), dot.mock_calls, dot.source, sep='\n')
#dot.view('round-table-transformed.gv') # noqa: E265
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