blob: 36b624981e9b736824b73982281987b47b224fe2 [file] [log] [blame]
"""
Common helper functions for tests.
"""
from __future__ import absolute_import, division, print_function
import keyword
import string
from collections import OrderedDict
from hypothesis import strategies as st
import attr
from attr import Attribute
from attr._make import NOTHING, make_class
def simple_class(cmp=False, repr=False, hash=False, str=False, slots=False,
frozen=False):
"""
Return a new simple class.
"""
return make_class(
"C", ["a", "b"],
cmp=cmp, repr=repr, hash=hash, init=True, slots=slots, str=str,
frozen=frozen,
)
def simple_attr(name, default=NOTHING, validator=None, repr=True,
cmp=True, hash=None, init=True):
"""
Return an attribute with a name and no other bells and whistles.
"""
return Attribute(
name=name, default=default, validator=validator, repr=repr,
cmp=cmp, hash=hash, init=init
)
class TestSimpleClass(object):
"""
Tests for the testing helper function `make_class`.
"""
def test_returns_class(self):
"""
Returns a class object.
"""
assert type is simple_class().__class__
def returns_distinct_classes(self):
"""
Each call returns a completely new class.
"""
assert simple_class() is not simple_class()
def gen_attr_names():
"""
Generate names for attributes, 'a'...'z', then 'aa'...'zz'.
~702 different attribute names should be enough in practice.
Some short strings (such as 'as') are keywords, so we skip them.
"""
lc = string.ascii_lowercase
for c in lc:
yield c
for outer in lc:
for inner in lc:
res = outer + inner
if keyword.iskeyword(res):
continue
yield outer + inner
def maybe_underscore_prefix(source):
"""
A generator to sometimes prepend an underscore.
"""
to_underscore = False
for val in source:
yield val if not to_underscore else '_' + val
to_underscore = not to_underscore
def _create_hyp_class(attrs):
"""
A helper function for Hypothesis to generate attrs classes.
"""
return make_class(
"HypClass", dict(zip(gen_attr_names(), attrs))
)
def _create_hyp_nested_strategy(simple_class_strategy):
"""
Create a recursive attrs class.
Given a strategy for building (simpler) classes, create and return
a strategy for building classes that have as an attribute: either just
the simpler class, a list of simpler classes, a tuple of simpler classes,
an ordered dict or a dict mapping the string "cls" to a simpler class.
"""
# Use a tuple strategy to combine simple attributes and an attr class.
def just_class(tup):
combined_attrs = list(tup[0])
combined_attrs.append(attr.ib(default=attr.Factory(tup[1])))
return _create_hyp_class(combined_attrs)
def list_of_class(tup):
default = attr.Factory(lambda: [tup[1]()])
combined_attrs = list(tup[0])
combined_attrs.append(attr.ib(default=default))
return _create_hyp_class(combined_attrs)
def tuple_of_class(tup):
default = attr.Factory(lambda: (tup[1](),))
combined_attrs = list(tup[0])
combined_attrs.append(attr.ib(default=default))
return _create_hyp_class(combined_attrs)
def dict_of_class(tup):
default = attr.Factory(lambda: {"cls": tup[1]()})
combined_attrs = list(tup[0])
combined_attrs.append(attr.ib(default=default))
return _create_hyp_class(combined_attrs)
def ordereddict_of_class(tup):
default = attr.Factory(lambda: OrderedDict([("cls", tup[1]())]))
combined_attrs = list(tup[0])
combined_attrs.append(attr.ib(default=default))
return _create_hyp_class(combined_attrs)
# A strategy producing tuples of the form ([list of attributes], <given
# class strategy>).
attrs_and_classes = st.tuples(list_of_attrs, simple_class_strategy)
return st.one_of(attrs_and_classes.map(just_class),
attrs_and_classes.map(list_of_class),
attrs_and_classes.map(tuple_of_class),
attrs_and_classes.map(dict_of_class),
attrs_and_classes.map(ordereddict_of_class))
bare_attrs = st.just(attr.ib(default=None))
int_attrs = st.integers().map(lambda i: attr.ib(default=i))
str_attrs = st.text().map(lambda s: attr.ib(default=s))
float_attrs = st.floats().map(lambda f: attr.ib(default=f))
dict_attrs = (st.dictionaries(keys=st.text(), values=st.integers())
.map(lambda d: attr.ib(default=d)))
simple_attrs_without_metadata = (bare_attrs | int_attrs | str_attrs |
float_attrs | dict_attrs)
@st.composite
def simple_attrs_with_metadata(draw):
"""
Create a simple attribute with arbitrary metadata.
"""
c_attr = draw(simple_attrs)
keys = st.booleans() | st.binary() | st.integers() | st.text()
vals = st.booleans() | st.binary() | st.integers() | st.text()
metadata = draw(st.dictionaries(keys=keys, values=vals))
return attr.ib(c_attr._default, c_attr._validator, c_attr.repr,
c_attr.cmp, c_attr.hash, c_attr.init, c_attr.convert,
metadata)
simple_attrs = simple_attrs_without_metadata | simple_attrs_with_metadata()
# Python functions support up to 255 arguments.
list_of_attrs = st.lists(simple_attrs, average_size=3, max_size=9)
@st.composite
def simple_classes(draw, slots=None, frozen=None, private_attrs=None):
"""
A strategy that generates classes with default non-attr attributes.
For example, this strategy might generate a class such as:
@attr.s(slots=True, frozen=True)
class HypClass:
a = attr.ib(default=1)
_b = attr.ib(default=None)
c = attr.ib(default='text')
_d = attr.ib(default=1.0)
c = attr.ib(default={'t': 1})
By default, all combinations of slots and frozen classes will be generated.
If `slots=True` is passed in, only slots classes will be generated, and
if `slots=False` is passed in, no slot classes will be generated. The same
applies to `frozen`.
By default, some attributes will be private (i.e. prefixed with an
underscore). If `private_attrs=True` is passed in, all attributes will be
private, and if `private_attrs=False`, no attributes will be private.
"""
attrs = draw(list_of_attrs)
frozen_flag = draw(st.booleans()) if frozen is None else frozen
slots_flag = draw(st.booleans()) if slots is None else slots
if private_attrs is None:
attr_names = maybe_underscore_prefix(gen_attr_names())
elif private_attrs is True:
attr_names = ('_' + n for n in gen_attr_names())
elif private_attrs is False:
attr_names = gen_attr_names()
cls_dict = dict(zip(attr_names, attrs))
post_init_flag = draw(st.booleans())
if post_init_flag:
def post_init(self):
pass
cls_dict["__attrs_post_init__"] = post_init
return make_class(
"HypClass",
cls_dict,
slots=slots_flag,
frozen=frozen_flag,
)
# st.recursive works by taking a base strategy (in this case, simple_classes)
# and a special function. This function receives a strategy, and returns
# another strategy (building on top of the base strategy).
nested_classes = st.recursive(
simple_classes(),
_create_hyp_nested_strategy,
max_leaves=10
)