_compat_test.py

# Copyright 2019 The Cirq Developers
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     https://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import collections
import dataclasses
import importlib
import logging
import multiprocessing
import os
import sys
import traceback
import types
import warnings
from types import ModuleType
from typing import Any, Callable, Dict, Optional, Tuple
from importlib.machinery import ModuleSpec
from unittest import mock


import numpy as np
import pandas as pd
import pytest
import sympy
from _pytest.outcomes import Failed

import cirq.testing
from cirq._compat import (
    block_overlapping_deprecation,
    cached_method,
    cached_property,
    proper_repr,
    dataclass_repr,
    deprecated,
    deprecated_parameter,
    proper_eq,
    deprecate_attributes,
    deprecated_class,
    deprecated_submodule,
    DeprecatedModuleLoader,
    DeprecatedModuleImportError,
)


def test_with_debug():
    assert cirq.__cirq_debug__.get()
    with cirq.with_debug(False):
        assert not cirq.__cirq_debug__.get()
        with cirq.with_debug(True):
            assert cirq.__cirq_debug__.get()
        assert not cirq.__cirq_debug__.get()
    assert cirq.__cirq_debug__.get()


def test_proper_repr():
    v = sympy.Symbol('t') * 3
    v2 = eval(proper_repr(v))
    assert v2 == v

    v = np.array([1, 2, 3], dtype=np.complex64)
    v2 = eval(proper_repr(v))
    np.testing.assert_array_equal(v2, v)
    assert v2.dtype == v.dtype


def test_proper_repr_data_frame():
    df = pd.DataFrame(
        index=[1, 2, 3], data=[[11, 21.0], [12, 22.0], [13, 23.0]], columns=['a', 'b']
    )
    df2 = eval(proper_repr(df))
    assert df2['a'].dtype == np.int64
    assert df2['b'].dtype == float
    pd.testing.assert_frame_equal(df2, df)

    df = pd.DataFrame(
        index=pd.Index([1, 2, 3], name='test'),
        data=[[11, 21.0], [12, 22.0], [13, 23.0]],
        columns=['a', 'b'],
    )
    df2 = eval(proper_repr(df))
    pd.testing.assert_frame_equal(df2, df)

    df = pd.DataFrame(
        index=pd.MultiIndex.from_tuples([(1, 2), (2, 3), (3, 4)], names=['x', 'y']),
        data=[[11, 21.0], [12, 22.0], [13, 23.0]],
        columns=pd.Index(['a', 'b'], name='c'),
    )
    df2 = eval(proper_repr(df))
    pd.testing.assert_frame_equal(df2, df)


def test_dataclass_repr_simple() -> None:
    @dataclasses.dataclass
    class TestClass1:
        x: int
        y: str
        doodle: Any = dataclasses.field(repr=False, default=None)

        def __repr__(self):
            return dataclass_repr(self)

    assert repr(TestClass1(5, 'hi')) == "cirq.TestClass1(x=5, y='hi')"


def test_dataclass_repr_numpy() -> None:
    @dataclasses.dataclass
    class TestClass2:
        x: np.ndarray

        def __repr__(self):
            return dataclass_repr(self, namespace='cirq.testing')

    tc = TestClass2(np.ones(3))
    assert (
        repr(tc)
        == "cirq.testing.TestClass2(x=np.array([1.0, 1.0, 1.0], dtype=np.dtype('float64')))"
    )


def test_proper_eq():
    assert proper_eq(1, 1)
    assert not proper_eq(1, 2)

    assert proper_eq(np.array([1, 2, 3]), np.array([1, 2, 3]))
    assert not proper_eq(np.array([1, 2, 3]), np.array([1, 2, 3, 4]))
    assert not proper_eq(np.array([1, 2, 3]), np.array([[1, 2, 3]]))
    assert not proper_eq(np.array([1, 2, 3]), np.array([1, 4, 3]))

    assert proper_eq(pd.Index([1, 2, 3]), pd.Index([1, 2, 3]))
    assert not proper_eq(pd.Index([1, 2, 3]), pd.Index([1, 2, 3, 4]))
    assert not proper_eq(pd.Index([1, 2, 3]), pd.Index([1, 4, 3]))


def test_deprecated_with_name():
    @deprecated(deadline='v1.2', fix='Roll some dice.', name='test_func')
    def f(a, b):
        return a + b

    with cirq.testing.assert_deprecated(
        '_compat_test.py:',
        'test_func was used',
        'will be removed in cirq v1.2',
        'Roll some dice.',
        deadline='v1.2',
    ):
        assert f(1, 2) == 3


def test_deprecated_with_property():
    class AClass(object):
        def __init__(self, a):
            self.a = a

        @property
        @deprecated(deadline='v1.2', fix='Stop using.', name='AClass.test_func')
        def f(self):
            return self.a

    instance = AClass(4)
    with cirq.testing.assert_deprecated(
        '_compat_test.py:',
        'AClass.test_func was used',
        'will be removed in cirq v1.2',
        'Stop using.',
        deadline='v1.2',
    ):
        assert instance.f == 4


def test_deprecated():
    def new_func(a, b):
        return a + b

    @deprecated(deadline='v1.2', fix='Roll some dice.')
    def old_func(*args, **kwargs):
        return new_func(*args, **kwargs)

    with cirq.testing.assert_deprecated(
        '_compat_test.py:',
        'old_func was used',
        'will be removed in cirq v1.2',
        'Roll some dice.',
        deadline='v1.2',
    ):
        assert old_func(1, 2) == 3

    with pytest.raises(
        ValueError, match='During testing using Cirq deprecated functionality is not allowed'
    ):
        old_func(1, 2)

    with pytest.raises(AssertionError, match='deadline should match vX.Y'):
        # pylint: disable=unused-variable
        # coverage: ignore
        @deprecated(deadline='invalid', fix='Roll some dice.')
        def badly_deprecated_func(*args, **kwargs):
            return new_func(*args, **kwargs)

        # pylint: enable=unused-variable


def test_deprecated_parameter():
    @deprecated_parameter(
        deadline='v1.2',
        fix='Double it yourself.',
        func_name='test_func',
        parameter_desc='double_count',
        match=lambda args, kwargs: 'double_count' in kwargs,
        rewrite=lambda args, kwargs: (args, {'new_count': kwargs['double_count'] * 2}),
    )
    def f(new_count):
        return new_count

    # Does not warn on usual use.
    with cirq.testing.assert_logs(count=0):
        assert f(1) == 1
        assert f(new_count=1) == 1

    with cirq.testing.assert_deprecated(
        '_compat_test.py:',
        'double_count parameter of test_func was used',
        'will be removed in cirq v1.2',
        'Double it yourself.',
        deadline='v1.2',
    ):
        # pylint: disable=unexpected-keyword-arg
        # pylint: disable=no-value-for-parameter
        assert f(double_count=1) == 2
        # pylint: enable=no-value-for-parameter
        # pylint: enable=unexpected-keyword-arg

    with pytest.raises(
        ValueError, match='During testing using Cirq deprecated functionality is not allowed'
    ):
        # pylint: disable=unexpected-keyword-arg
        # pylint: disable=no-value-for-parameter
        f(double_count=1)
        # pylint: enable=no-value-for-parameter
        # pylint: enable=unexpected-keyword-arg

    with pytest.raises(AssertionError, match='deadline should match vX.Y'):

        @deprecated_parameter(
            deadline='invalid',
            fix='Double it yourself.',
            func_name='test_func',
            parameter_desc='double_count',
            match=lambda args, kwargs: 'double_count' in kwargs,
            rewrite=lambda args, kwargs: (args, {'new_count': kwargs['double_count'] * 2}),
        )
        # pylint: disable=unused-variable
        # coverage: ignore
        def f_with_badly_deprecated_param(new_count):
            return new_count

        # pylint: enable=unused-variable


def test_wrap_module():
    my_module = types.ModuleType('my_module', 'my doc string')
    my_module.foo = 'foo'
    my_module.bar = 'bar'
    my_module.__spec__ = ModuleSpec('my_module', loader=None)
    assert 'foo' in my_module.__dict__
    assert 'bar' in my_module.__dict__
    assert 'zoo' not in my_module.__dict__

    with pytest.raises(AssertionError, match='deadline should match vX.Y'):
        deprecate_attributes(my_module, {'foo': ('invalid', 'use bar instead')})

    # temporarily update sys.modules so deprecate_attributes can find my_module
    sys.modules['my_module'] = my_module
    wrapped = deprecate_attributes('my_module', {'foo': ('v0.6', 'use bar instead')})
    assert wrapped is sys.modules.pop('my_module')
    # Dunder methods
    assert wrapped.__doc__ == 'my doc string'
    assert wrapped.__name__ == 'my_module'
    assert wrapped.__spec__ is my_module.__spec__
    # Verify __spec__ setter in the wrapped module
    wrapped.__spec__ = ModuleSpec('my_module', loader=None)
    assert my_module.__spec__ is wrapped.__spec__
    # Test dict is correct.
    assert 'foo' in wrapped.__dict__
    assert 'bar' in wrapped.__dict__
    assert 'zoo' not in wrapped.__dict__

    # Deprecation capability.
    with cirq.testing.assert_deprecated(
        '_compat_test.py:',
        'foo was used but is deprecated.',
        'will be removed in cirq v0.6',
        'use bar instead',
        deadline='v0.6',
    ):
        _ = wrapped.foo

    with pytest.raises(
        ValueError, match='During testing using Cirq deprecated functionality is not allowed'
    ):
        _ = wrapped.foo

    with cirq.testing.assert_logs(count=0):
        _ = wrapped.bar


def test_deprecate_attributes_assert_attributes_in_sys_modules():
    subprocess_context(_test_deprecate_attributes_assert_attributes_in_sys_modules)()


def _test_deprecate_attributes_assert_attributes_in_sys_modules():
    """Ensure submodule attributes are consistent with sys.modules items."""
    import cirq.testing._compat_test_data.module_a as module_a0

    module_a1 = deprecate_attributes(
        'cirq.testing._compat_test_data.module_a',
        {'MODULE_A_ATTRIBUTE': ('v0.6', 'use plain string instead')},
    )

    assert module_a1 is not module_a0
    assert module_a1 is cirq.testing._compat_test_data.module_a
    assert module_a1 is sys.modules['cirq.testing._compat_test_data.module_a']


def test_deprecated_class():
    class NewClass:
        def __init__(self, a):
            self._a = a

        @property
        def a(self):
            return self._a

        def __repr__(self):
            return f'NewClass: {self.a}'

        @classmethod
        def hello(cls):
            return f'hello {cls}'

    @deprecated_class(deadline='v1.2', fix='theFix', name='foo')
    class OldClass(NewClass):
        """The OldClass docs"""

    assert OldClass.__doc__.startswith('THIS CLASS IS DEPRECATED')
    assert 'OldClass docs' in OldClass.__doc__

    with cirq.testing.assert_deprecated(
        '_compat_test.py:',
        'foo was used but is deprecated',
        'will be removed in cirq v1.2',
        'theFix',
        deadline='v1.2',
    ):
        old_obj = OldClass('1')
        assert repr(old_obj) == 'NewClass: 1'
        assert 'OldClass' in old_obj.hello()

    with pytest.raises(
        ValueError, match='During testing using Cirq deprecated functionality is not allowed'
    ):
        OldClass('1')

    with pytest.raises(AssertionError, match='deadline should match vX.Y'):
        # pylint: disable=unused-variable
        # coverage: ignore
        @deprecated_class(deadline='invalid', fix='theFix', name='foo')
        class BadlyDeprecatedClass(NewClass):
            ...

        # pylint: enable=unused-variable


def _from_parent_import_deprecated():
    from cirq.testing._compat_test_data import fake_a

    assert fake_a.MODULE_A_ATTRIBUTE == 'module_a'


def _import_deprecated_assert_sub():
    import cirq.testing._compat_test_data.fake_a  # type: ignore

    assert cirq.testing._compat_test_data.fake_a.module_b.MODULE_B_ATTRIBUTE == 'module_b'


def _from_deprecated_import_sub():
    from cirq.testing._compat_test_data.fake_a import module_b

    assert module_b.MODULE_B_ATTRIBUTE == 'module_b'


def _import_deprecated_first_new_second():
    """To ensure that module_a gets initialized only once.

    Note that the single execution of _compat_test_data and module_a is asserted
    in _test_deprecated_module_inner by counting the INFO messages emitted by
    the modules ('init:compat_test_data' and 'init:module_a').
    """

    from cirq.testing._compat_test_data.fake_a import module_b

    assert module_b.MODULE_B_ATTRIBUTE == 'module_b'

    # the DeprecatedModuleLoader should set the refs for both modules
    assert 'cirq.testing._compat_test_data.fake_a' in sys.modules
    assert 'cirq.testing._compat_test_data.module_a' in sys.modules

    assert (
        sys.modules['cirq.testing._compat_test_data.fake_a']
        == sys.modules['cirq.testing._compat_test_data.module_a']
    )

    from cirq.testing._compat_test_data.module_a import module_b

    assert module_b.MODULE_B_ATTRIBUTE == 'module_b'


def _import_new_first_deprecated_second():
    """To ensure that module_a gets initialized only once.

    It is the same as _import_deprecated_first_new_second just with different import order.
    See that for more details.
    """
    from cirq.testing._compat_test_data.module_a import module_b

    assert module_b.MODULE_B_ATTRIBUTE == 'module_b'

    # the DeprecatedModuleLoader should set the ref only for module_a
    assert 'cirq.testing._compat_test_data.fake_a' not in sys.modules
    assert 'cirq.testing._compat_test_data.module_a' in sys.modules

    from cirq.testing._compat_test_data.fake_a import module_b

    assert 'cirq.testing._compat_test_data.fake_a' in sys.modules
    assert (
        sys.modules['cirq.testing._compat_test_data.fake_a']
        == sys.modules['cirq.testing._compat_test_data.module_a']
    )

    assert module_b.MODULE_B_ATTRIBUTE == 'module_b'


def _from_deprecated_import_sub_of_sub():
    """Ensures that the deprecation warning level is correct."""
    from cirq.testing._compat_test_data.module_a.module_b import module_c

    assert module_c.MODULE_C_ATTRIBUTE == 'module_c'
    from cirq.testing._compat_test_data.fake_a.module_b import module_c  # type: ignore

    assert module_c.MODULE_C_ATTRIBUTE == 'module_c'


def _import_multiple_deprecated():
    """Ensures that multiple deprecations play well together."""
    from cirq.testing._compat_test_data.module_a.module_b import module_c

    assert module_c.MODULE_C_ATTRIBUTE == 'module_c'
    from cirq.testing._compat_test_data.fake_a.module_b import module_c

    assert module_c.MODULE_C_ATTRIBUTE == 'module_c'
    from cirq.testing._compat_test_data.fake_b import module_c  # type: ignore

    assert module_c.MODULE_C_ATTRIBUTE == 'module_c'


def _deprecate_grandchild_assert_attributes_in_sys_modules():
    """Ensure submodule attributes are identical to sys.modules values."""
    import cirq.testing._compat_test_data.module_a.fake_ab  # type: ignore

    assert (
        cirq.testing._compat_test_data.module_a.fake_ab
        is sys.modules['cirq.testing._compat_test_data.module_a.fake_ab']
    )
    assert (
        cirq.testing._compat_test_data.module_a
        is sys.modules['cirq.testing._compat_test_data.module_a']
    )
    assert cirq.testing._compat_test_data is sys.modules['cirq.testing._compat_test_data']


def _new_module_in_different_parent():
    from cirq.testing._compat_test_data.fake_ops import raw_types  # type: ignore

    assert raw_types.Qid == cirq.Qid


def _find_spec_deprecated_multiple_times():
    """to ensure the idempotency of the aliasing loader change"""
    # sets up the DeprecationFinders
    import importlib.util

    # first import, the loader is the regular loader on the spec
    assert importlib.util.find_spec('cirq.testing._compat_test_data.fake_a')
    # second import it might be the aliasing loader already
    assert importlib.util.find_spec('cirq.testing._compat_test_data.fake_a')


def _import_parent_use_constant_from_deprecated_module_attribute():
    """to ensure that module initializations set attributes correctly"""
    # sets up the DeprecationFinders
    import cirq.testing._compat_test_data

    # the parent should have fake_a set on it as an attribute - just like
    # a regular module import (e.g. cirq.ops)
    # should have a DUPE_CONSTANT as its imported from the dupe submodule
    assert cirq.testing._compat_test_data.fake_a.DUPE_CONSTANT is False

    assert 'module_a for module deprecation tests' in cirq.testing._compat_test_data.fake_a.__doc__
    assert 'Test module for deprecation testing' in cirq.testing._compat_test_data.__doc__


def _import_deprecated_sub_use_constant():
    """to ensure that submodule initializations set attributes correctly"""
    # sets up the DeprecationFinders
    import cirq.testing._compat_test_data.fake_a.dupe  # type: ignore

    # should have a DUPE_CONSTANT as its defined on it, set to False
    assert cirq.testing._compat_test_data.fake_a.dupe.DUPE_CONSTANT is False


def _import_deprecated_same_name_in_earlier_subtree():
    from cirq.testing._compat_test_data.fake_a.sub.subsub.dupe import DUPE_CONSTANT  # type: ignore

    assert DUPE_CONSTANT


def _import_top_level_deprecated():
    from cirq.testing._compat_test_data.fake_freezegun import api  # type: ignore
    import time

    assert api.real_time == time.time


def _repeated_import_path():
    """to ensure that the highly unlikely repeated subpath import doesn't interfere"""

    # pylint: disable=line-too-long
    from cirq.testing._compat_test_data.repeated_child.cirq.testing._compat_test_data.repeated_child import (  # type: ignore
        child,
    )

    assert child.CHILD_ATTRIBUTE == 'child'


def _type_repr_in_deprecated_module():
    # initialize the DeprecatedModuleFinders
    # pylint: disable=unused-import
    import cirq.testing._compat_test_data.fake_a as mod_a

    expected_repr = "<class 'cirq.testing._compat_test_data.module_a.types.SampleType'>"
    assert repr(mod_a.SampleType) == expected_repr


old_parent = 'cirq.testing._compat_test_data'

# this is where the deprecation error should show where the deprecated usage
# has occured, which is this file
_deprecation_origin = ['_compat_test.py:']

# see cirq_compat_test_data/__init__.py for the setup code
_fake_a_deprecation_msg = [
    f'{old_parent}.fake_a was used but is deprecated',
    f'Use {old_parent}.module_a instead',
] + _deprecation_origin

# see cirq_compat_test_data/__init__.py for the setup code
_fake_b_deprecation_msg = [
    f'{old_parent}.fake_b was used but is deprecated',
    f'Use {old_parent}.module_a.module_b instead',
] + _deprecation_origin

# see cirq_compat_test_data/__init__.py for the setup code
_fake_ab_deprecation_msg = [
    f'{old_parent}.module_a.fake_ab was used but is deprecated',
    f'Use {old_parent}.module_a.module_b instead',
] + _deprecation_origin

# see cirq_compat_test_data/__init__.py for the setup code
_fake_ops_deprecation_msg = [
    f'{old_parent}.fake_ops was used but is deprecated',
    'Use cirq.ops instead',
] + _deprecation_origin


# see cirq_compat_test_data/__init__.py for the setup code
_fake_freezegun_deprecation_msg = [
    f'{old_parent}.fake_freezegun was used but is deprecated',
    'Use freezegun instead',
] + _deprecation_origin

# see cirq_compat_test_data/__init__.py for the setup code
_repeated_child_deprecation_msg = [
    f'{old_parent}.repeated_child was used but is deprecated',
    f'Use {old_parent}.repeated instead',
] + _deprecation_origin


def _trace_unhandled_exceptions(*args, queue: 'multiprocessing.Queue', func: Callable, **kwargs):
    try:
        func(*args, **kwargs)
        queue.put(None)
    except BaseException as ex:
        msg = str(ex)
        queue.put((type(ex).__name__, msg, traceback.format_exc()))


def subprocess_context(test_func):
    """Ensures that sys.modules changes in subprocesses won't impact the parent process."""
    assert callable(test_func), (
        "subprocess_context expects a function. Did you call the function instead of passing "
        "it to this method?"
    )

    import os

    ctx = multiprocessing.get_context('spawn' if os.name == 'nt' else 'fork')

    exception = ctx.Queue()

    def isolated_func(*args, **kwargs):
        kwargs['queue'] = exception
        kwargs['func'] = test_func
        p = ctx.Process(target=_trace_unhandled_exceptions, args=args, kwargs=kwargs)
        p.start()
        p.join()
        result = exception.get()
        if result:
            # coverage: ignore
            ex_type, msg, ex_trace = result
            if ex_type == "Skipped":
                warnings.warn(f"Skipping: {ex_type}: {msg}\n{ex_trace}")
                pytest.skip(f'{ex_type}: {msg}\n{ex_trace}')
            else:
                pytest.fail(f'{ex_type}: {msg}\n{ex_trace}')

    return isolated_func


@mock.patch.dict(os.environ, {"CIRQ_FORCE_DEDUPE_MODULE_DEPRECATION": "1"})
@pytest.mark.parametrize(
    'outdated_method,deprecation_messages',
    [
        (_from_parent_import_deprecated, [_fake_a_deprecation_msg]),
        (_import_deprecated_assert_sub, [_fake_a_deprecation_msg]),
        (_from_deprecated_import_sub, [_fake_a_deprecation_msg]),
        (_import_deprecated_first_new_second, [_fake_a_deprecation_msg]),
        (_import_new_first_deprecated_second, [_fake_a_deprecation_msg]),
        (_import_multiple_deprecated, [_fake_a_deprecation_msg, _fake_b_deprecation_msg]),
        (_deprecate_grandchild_assert_attributes_in_sys_modules, [_fake_ab_deprecation_msg]),
        (_new_module_in_different_parent, [_fake_ops_deprecation_msg]),
        # ignore the frame requirement - as we are using find_spec from importlib, it
        # is detected as an 'internal' frame by warnings
        (_find_spec_deprecated_multiple_times, [_fake_a_deprecation_msg[:-1]]),
        (_import_parent_use_constant_from_deprecated_module_attribute, [_fake_a_deprecation_msg]),
        (_import_deprecated_sub_use_constant, [_fake_a_deprecation_msg]),
        (_import_deprecated_same_name_in_earlier_subtree, [_fake_a_deprecation_msg]),
        (_import_top_level_deprecated, [_fake_freezegun_deprecation_msg]),
        (_from_deprecated_import_sub_of_sub, [_fake_a_deprecation_msg]),
        (_repeated_import_path, [_repeated_child_deprecation_msg]),
        (_type_repr_in_deprecated_module, [_fake_a_deprecation_msg]),
    ],
)
def test_deprecated_module(outdated_method, deprecation_messages):
    subprocess_context(_test_deprecated_module_inner)(outdated_method, deprecation_messages)


def _test_deprecated_module_inner(outdated_method, deprecation_messages):
    # ensure that both packages are initialized exactly once
    import cirq

    with cirq.testing.assert_logs(
        'init:compat_test_data',
        'init:module_a',
        min_level=logging.INFO,
        max_level=logging.INFO,
        count=2,
    ):
        with cirq.testing.assert_deprecated(
            *[msg for dep in deprecation_messages for msg in dep],
            deadline='v0.20',
            count=len(deprecation_messages),
        ):
            warnings.simplefilter('always')
            outdated_method()


def test_same_name_submodule_earlier_in_subtree():
    """Tests whether module resolution works in the right order.

    We have two packages with a bool `DUPE_CONSTANT` attribute each:
       1. cirq.testing._compat_test_data.module_a.sub.dupe.DUPE_CONSTANT=True # the right one
       2. cirq.testing._compat_test_data.module_a.dupe.DUPE_CONSTANT=False # the wrong one

    If the new module's (in this case cirq.testing._compat_test_data.module_a) path has precedence
    during module spec resolution, dupe number 2 is going to get resolved.

    You might wonder where this comes up in cirq. There was a bug where the lookup path was not in
    the right order. The motivating example is cirq.ops.calibration vs the
    cirq.ops.engine.calibration packages. The wrong resolution resulted in false circular
    imports!
    """
    subprocess_context(_test_same_name_submodule_earlier_in_subtree_inner)()


def _test_same_name_submodule_earlier_in_subtree_inner():
    from cirq.testing._compat_test_data.module_a.sub.subsub.dupe import DUPE_CONSTANT

    assert DUPE_CONSTANT


def test_metadata_search_path():
    # to cater for metadata path finders
    # https://docs.python.org/3/library/importlib.metadata.html#extending-the-search-algorithm
    subprocess_context(_test_metadata_search_path_inner)()


def _test_metadata_search_path_inner():
    # initialize the DeprecatedModuleFinders
    # pylint: disable=unused-import
    import cirq.testing._compat_test_data.module_a

    try:
        # importlib.metadata for python 3.8+
        # coverage: ignore
        import importlib.metadata as m
    except:  # coverage: ignore
        # coverage: ignore
        # importlib_metadata for python <3.8
        m = pytest.importorskip("importlib_metadata")

    assert m.metadata('flynt')


def test_metadata_distributions_after_deprecated_submodule():
    subprocess_context(_test_metadata_distributions_after_deprecated_submodule)()


def _test_metadata_distributions_after_deprecated_submodule():
    # verify deprecated_submodule does not break importlib_metadata.distributions()
    # See https://github.com/quantumlib/Cirq/issues/4729
    deprecated_submodule(
        new_module_name='cirq.neutral_atoms',
        old_parent='cirq',
        old_child='swiss_atoms',
        deadline="v0.14",
        create_attribute=True,
    )
    m = pytest.importorskip("importlib_metadata")
    distlist = list(m.distributions())
    assert all(isinstance(d.name, str) for d in distlist)


def test_parent_spec_after_deprecated_submodule():
    subprocess_context(_test_parent_spec_after_deprecated_submodule)()


def _test_parent_spec_after_deprecated_submodule():
    import cirq.testing._compat_test_data

    assert cirq.testing._compat_test_data.__spec__.name == 'cirq.testing._compat_test_data'


def test_type_repr_in_new_module():
    # to cater for metadata path finders
    # https://docs.python.org/3/library/importlib.metadata.html#extending-the-search-algorithm
    subprocess_context(_test_type_repr_in_new_module_inner)()


def _test_type_repr_in_new_module_inner():
    # initialize the DeprecatedModuleFinders
    # pylint: disable=unused-import
    import cirq.testing._compat_test_data.module_a as mod_a

    expected_repr = "<class 'cirq.testing._compat_test_data.module_a.types.SampleType'>"
    assert repr(mod_a.SampleType) == expected_repr


def test_deprecated_module_deadline_validation():
    with pytest.raises(AssertionError, match='deadline should match vX.Y'):
        deprecated_submodule(
            new_module_name='new',
            old_parent='old_p',
            old_child='old_ch',
            deadline='invalid',
            create_attribute=False,
        )


def _test_broken_module_1_inner():
    with pytest.raises(
        DeprecatedModuleImportError,
        match="missing_module cannot be imported. " "The typical reasons",
    ):
        # pylint: disable=unused-import
        import cirq.testing._compat_test_data.broken_ref as br  # type: ignore


def _test_broken_module_2_inner():
    warnings.simplefilter('always')
    with cirq.testing.assert_deprecated(deadline="v0.20", count=None):
        with pytest.raises(
            DeprecatedModuleImportError,
            match="missing_module cannot be imported. The typical reasons",
        ):
            # note that this passes
            from cirq.testing._compat_test_data import broken_ref

            # but when you try to use it
            broken_ref.something()


def _test_broken_module_3_inner():
    import cirq.testing._compat_test_data

    warnings.simplefilter('always')
    with cirq.testing.assert_deprecated(deadline="v0.20", count=None):
        with pytest.raises(
            DeprecatedModuleImportError,
            match="missing_module cannot be imported. The typical reasons",
        ):
            cirq.testing._compat_test_data.broken_ref.something()


def test_deprecated_module_error_handling_1():
    subprocess_context(_test_broken_module_1_inner)()


def test_deprecated_module_error_handling_2():
    subprocess_context(_test_broken_module_2_inner)()


def test_deprecated_module_error_handling_3():
    subprocess_context(_test_broken_module_3_inner)()


def test_new_module_is_top_level():
    subprocess_context(_test_new_module_is_top_level_inner)()


def _test_new_module_is_top_level_inner():
    # sets up the DeprecationFinders
    # pylint: disable=unused-import
    import cirq.testing._compat_test_data

    # imports a top level module that was also deprecated
    from freezegun import api
    import time

    assert api.real_time == time.time


def test_import_deprecated_with_no_attribute():
    subprocess_context(_test_import_deprecated_with_no_attribute_inner)()


def _test_import_deprecated_with_no_attribute_inner():
    """to ensure that create_attribute=False works too"""

    # sets up the DeprecationFinders - fake_b is setup with create_attribute=False
    import cirq.testing._compat_test_data

    # the parent module should not have fake_b as an attribute
    assert not hasattr(cirq.testing._compat_test_data, 'fake_b')


def test_loader_cleanup_on_failure():
    class FakeLoader(importlib.abc.Loader):
        def exec_module(self, module: ModuleType) -> None:
            raise KeyboardInterrupt()

    with pytest.raises(KeyboardInterrupt):
        module = types.ModuleType('old')
        DeprecatedModuleLoader(FakeLoader(), 'old', 'new').exec_module(module)

    assert 'old' not in sys.modules
    assert 'new' not in sys.modules


def test_loader_create_module():
    class EmptyLoader(importlib.abc.Loader):
        pass

    dml = DeprecatedModuleLoader(EmptyLoader(), 'old', 'new')
    # the default implementation is from the abstract class, which is just pass
    assert dml.create_module('test') is None

    fake_mod = ModuleType('hello')

    class CreateModuleLoader(importlib.abc.Loader):
        def create_module(self, spec: ModuleSpec) -> Optional[ModuleType]:
            return fake_mod

    assert (
        DeprecatedModuleLoader(CreateModuleLoader(), 'old', 'new').create_module(None) == fake_mod
    )


def test_deprecated_module_loader_load_module_wrapper():
    hello_module = types.ModuleType('hello')

    class StubLoader(importlib.abc.Loader):
        def load_module(self, fullname: str) -> ModuleType:
            # we simulate loader behavior - it is assumed that loaders will set the
            # module cache with the loaded module
            sys.modules[fullname] = hello_module
            return hello_module

    with pytest.raises(AssertionError, match="for old was asked to load something_else"):
        DeprecatedModuleLoader(StubLoader(), 'old', 'new').load_module('something_else')

    # new module already loaded
    sys.modules['new_hello'] = hello_module
    assert (
        DeprecatedModuleLoader(StubLoader(), 'old_hello', 'new_hello').load_module('old_hello')
        == hello_module
    )
    assert 'old_hello' in sys.modules and sys.modules['old_hello'] == sys.modules['new_hello']
    del sys.modules['new_hello']
    del sys.modules['old_hello']

    # new module is not loaded
    assert (
        DeprecatedModuleLoader(StubLoader(), 'old_hello', 'new_hello').load_module('old_hello')
        == hello_module
    )
    assert 'new_hello' in sys.modules
    assert 'old_hello' in sys.modules and sys.modules['old_hello'] == sys.modules['new_hello']
    del sys.modules['new_hello']
    del sys.modules['old_hello']


def test_deprecated_module_loader_repr():
    class StubLoader(importlib.abc.Loader):
        def module_repr(self, module: ModuleType) -> str:
            return 'hello'

    module = types.ModuleType('old')
    assert (
        DeprecatedModuleLoader(StubLoader(), 'old_hello', 'new_hello').module_repr(module)
        == 'hello'
    )


def test_subprocess_test_failure():
    with pytest.raises(Failed, match='ValueError.*this fails'):
        subprocess_context(_test_subprocess_test_failure_inner)()


def _test_subprocess_test_failure_inner():
    raise ValueError('this fails')


def test_dir_is_still_valid():
    subprocess_context(_dir_is_still_valid_inner)()


def _dir_is_still_valid_inner():
    """to ensure that create_attribute=True keeps the dir(module) intact"""

    import cirq.testing._compat_test_data as mod

    for m in ['fake_a', 'info', 'module_a', 'sys']:
        assert m in dir(mod)


def test_block_overlapping_deprecation():
    @deprecated(fix="Don't use g.", deadline="v1000.0")
    def g(y):
        return y - 4

    @deprecated(fix="Don't use f.", deadline="v1000.0")
    def f(x):
        with block_overlapping_deprecation('g'):
            return [g(i + 1) for i in range(x)]

    with cirq.testing.assert_deprecated('f', deadline='v1000.0', count=1):
        f(5)


def test_cached_property():
    class Foo:
        def __init__(self):
            self.bar_calls = 0

        @cached_property
        def bar(self):
            self.bar_calls += 1
            return []

    foo = Foo()
    bar = foo.bar
    bar2 = foo.bar
    assert bar2 is bar
    assert foo.bar_calls == 1


class Bar:
    def __init__(self) -> None:
        self.foo_calls: Dict[int, int] = collections.Counter()
        self.bar_calls: Dict[int, int] = collections.Counter()

    @cached_method
    def foo(self, n: int) -> Tuple[int, int]:
        self.foo_calls[n] += 1
        return (id(self), n)

    @cached_method(maxsize=1)
    def bar(self, n: int) -> Tuple[int, int]:
        self.bar_calls[n] += 1
        return (id(self), 2 * n)


def test_cached_method():
    b = Bar()
    assert b.foo(123) == b.foo(123) == b.foo(123) == (id(b), 123)
    assert b.foo(234) == b.foo(234) == b.foo(234) == (id(b), 234)
    assert b.foo_calls == {123: 1, 234: 1}

    assert b.bar(123) == b.bar(123) == (id(b), 123 * 2)
    assert b.bar_calls == {123: 1}
    assert b.bar(234) == b.bar(234) == (id(b), 234 * 2)
    assert b.bar_calls == {123: 1, 234: 1}
    assert b.bar(123) == b.bar(123) == (id(b), 123 * 2)
    assert b.bar_calls == {123: 2, 234: 1}