reflex/tests/test_state.py

from __future__ import annotations

import asyncio
import copy
import datetime
import functools
import json
import os
import sys
from typing import Dict, Generator, List
from unittest.mock import AsyncMock, Mock

import pytest
from plotly.graph_objects import Figure

import reflex as rx
from reflex.base import Base
from reflex.constants import CompileVars, RouteVar, SocketEvent
from reflex.event import Event, EventHandler
from reflex.state import (
    ImmutableStateError,
    LockExpiredError,
    MutableProxy,
    State,
    StateManager,
    StateManagerMemory,
    StateManagerRedis,
    StateProxy,
    StateUpdate,
)
from reflex.utils import prerequisites
from reflex.vars import BaseVar, ComputedVar

from .states import GenState

CI = bool(os.environ.get("CI", False))
LOCK_EXPIRATION = 2000 if CI else 100
LOCK_EXPIRE_SLEEP = 2.5 if CI else 0.2


class Object(Base):
    """A test object fixture."""

    prop1: int = 42
    prop2: str = "hello"


class TestState(State):
    """A test state."""

    # Set this class as not test one
    __test__ = False

    num1: int
    num2: float = 3.14
    key: str
    map_key: str = "a"
    array: List[float] = [1, 2, 3.14]
    mapping: Dict[str, List[int]] = {"a": [1, 2, 3], "b": [4, 5, 6]}
    obj: Object = Object()
    complex: Dict[int, Object] = {1: Object(), 2: Object()}
    fig: Figure = Figure()
    dt: datetime.datetime = datetime.datetime.fromisoformat("1989-11-09T18:53:00+01:00")

    @ComputedVar
    def sum(self) -> float:
        """Dynamically sum the numbers.

        Returns:
            The sum of the numbers.
        """
        return self.num1 + self.num2

    @ComputedVar
    def upper(self) -> str:
        """Uppercase the key.

        Returns:
            The uppercased key.
        """
        return self.key.upper()

    def do_something(self):
        """Do something."""
        pass


class ChildState(TestState):
    """A child state fixture."""

    value: str
    count: int = 23

    def change_both(self, value: str, count: int):
        """Change both the value and count.

        Args:
            value: The new value.
            count: The new count.
        """
        self.value = value.upper()
        self.count = count * 2


class ChildState2(TestState):
    """A child state fixture."""

    value: str


class GrandchildState(ChildState):
    """A grandchild state fixture."""

    value2: str

    def do_nothing(self):
        """Do something."""
        pass


class DateTimeState(State):
    """A State with some datetime fields."""

    d: datetime.date = datetime.date.fromisoformat("1989-11-09")
    dt: datetime.datetime = datetime.datetime.fromisoformat("1989-11-09T18:53:00+01:00")
    t: datetime.time = datetime.time.fromisoformat("18:53:00+01:00")
    td: datetime.timedelta = datetime.timedelta(days=11, minutes=11)


@pytest.fixture
def test_state() -> TestState:
    """A state.

    Returns:
        A test state.
    """
    return TestState()  # type: ignore


@pytest.fixture
def child_state(test_state) -> ChildState:
    """A child state.

    Args:
        test_state: A test state.

    Returns:
        A test child state.
    """
    child_state = test_state.get_substate(["child_state"])
    assert child_state is not None
    return child_state


@pytest.fixture
def child_state2(test_state) -> ChildState2:
    """A second child state.

    Args:
        test_state: A test state.

    Returns:
        A second test child state.
    """
    child_state2 = test_state.get_substate(["child_state2"])
    assert child_state2 is not None
    return child_state2


@pytest.fixture
def grandchild_state(child_state) -> GrandchildState:
    """A state.

    Args:
        child_state: A child state.

    Returns:
        A test state.
    """
    grandchild_state = child_state.get_substate(["grandchild_state"])
    assert grandchild_state is not None
    return grandchild_state


def test_base_class_vars(test_state):
    """Test that the class vars are set correctly.

    Args:
        test_state: A state.
    """
    fields = test_state.get_fields()
    cls = type(test_state)

    for field in fields:
        if field in test_state.get_skip_vars():
            continue
        prop = getattr(cls, field)
        assert isinstance(prop, BaseVar)
        assert prop.name == field

    assert cls.num1.type_ == int
    assert cls.num2.type_ == float
    assert cls.key.type_ == str


def test_computed_class_var(test_state):
    """Test that the class computed vars are set correctly.

    Args:
        test_state: A state.
    """
    cls = type(test_state)
    vars = [(prop.name, prop.type_) for prop in cls.computed_vars.values()]
    assert ("sum", float) in vars
    assert ("upper", str) in vars


def test_class_vars(test_state):
    """Test that the class vars are set correctly.

    Args:
        test_state: A state.
    """
    cls = type(test_state)
    assert set(cls.vars.keys()) == {
        CompileVars.IS_HYDRATED,  # added by hydrate_middleware to all State
        "num1",
        "num2",
        "key",
        "map_key",
        "array",
        "mapping",
        "obj",
        "complex",
        "sum",
        "upper",
        "fig",
        "dt",
    }


def test_event_handlers(test_state):
    """Test that event handler is set correctly.

    Args:
        test_state: A state.
    """
    expected = {
        "do_something",
        "set_array",
        "set_complex",
        "set_fig",
        "set_key",
        "set_mapping",
        "set_num1",
        "set_num2",
        "set_obj",
    }

    cls = type(test_state)
    assert set(cls.event_handlers.keys()).intersection(expected) == expected


def test_default_value(test_state):
    """Test that the default value of a var is correct.

    Args:
        test_state: A state.
    """
    assert test_state.num1 == 0
    assert test_state.num2 == 3.14
    assert test_state.key == ""
    assert test_state.sum == 3.14
    assert test_state.upper == ""


def test_computed_vars(test_state):
    """Test that the computed var is computed correctly.

    Args:
        test_state: A state.
    """
    test_state.num1 = 1
    test_state.num2 = 4
    assert test_state.sum == 5
    test_state.key = "hello world"
    assert test_state.upper == "HELLO WORLD"


def test_dict(test_state):
    """Test that the dict representation of a state is correct.

    Args:
        test_state: A state.
    """
    substates = {"child_state", "child_state2"}
    assert set(test_state.dict().keys()) == set(test_state.vars.keys()) | substates
    assert (
        set(test_state.dict(include_computed=False).keys())
        == set(test_state.base_vars) | substates
    )


def test_default_setters(test_state):
    """Test that we can set default values.

    Args:
        test_state: A state.
    """
    for prop_name in test_state.base_vars:
        # Each base var should have a default setter.
        assert hasattr(test_state, f"set_{prop_name}")


def test_class_indexing_with_vars():
    """Test that we can index into a state var with another var."""
    prop = TestState.array[TestState.num1]
    assert str(prop) == "{test_state.array.at(test_state.num1)}"

    prop = TestState.mapping["a"][TestState.num1]
    assert str(prop) == '{test_state.mapping["a"].at(test_state.num1)}'

    prop = TestState.mapping[TestState.map_key]
    assert str(prop) == "{test_state.mapping[test_state.map_key]}"


def test_class_attributes():
    """Test that we can get class attributes."""
    prop = TestState.obj.prop1
    assert str(prop) == "{test_state.obj.prop1}"

    prop = TestState.complex[1].prop1
    assert str(prop) == "{test_state.complex[1].prop1}"


def test_get_parent_state():
    """Test getting the parent state."""
    assert TestState.get_parent_state() is None
    assert ChildState.get_parent_state() == TestState
    assert ChildState2.get_parent_state() == TestState
    assert GrandchildState.get_parent_state() == ChildState


def test_get_substates():
    """Test getting the substates."""
    assert TestState.get_substates() == {ChildState, ChildState2}
    assert ChildState.get_substates() == {GrandchildState}
    assert ChildState2.get_substates() == set()
    assert GrandchildState.get_substates() == set()


def test_get_name():
    """Test getting the name of a state."""
    assert TestState.get_name() == "test_state"
    assert ChildState.get_name() == "child_state"
    assert ChildState2.get_name() == "child_state2"
    assert GrandchildState.get_name() == "grandchild_state"


def test_get_full_name():
    """Test getting the full name."""
    assert TestState.get_full_name() == "test_state"
    assert ChildState.get_full_name() == "test_state.child_state"
    assert ChildState2.get_full_name() == "test_state.child_state2"
    assert GrandchildState.get_full_name() == "test_state.child_state.grandchild_state"


def test_get_class_substate():
    """Test getting the substate of a class."""
    assert TestState.get_class_substate(("child_state",)) == ChildState
    assert TestState.get_class_substate(("child_state2",)) == ChildState2
    assert ChildState.get_class_substate(("grandchild_state",)) == GrandchildState
    assert (
        TestState.get_class_substate(("child_state", "grandchild_state"))
        == GrandchildState
    )
    with pytest.raises(ValueError):
        TestState.get_class_substate(("invalid_child",))
    with pytest.raises(ValueError):
        TestState.get_class_substate(
            (
                "child_state",
                "invalid_child",
            )
        )


def test_get_class_var():
    """Test getting the var of a class."""
    assert TestState.get_class_var(("num1",)).equals(TestState.num1)
    assert TestState.get_class_var(("num2",)).equals(TestState.num2)
    assert ChildState.get_class_var(("value",)).equals(ChildState.value)
    assert GrandchildState.get_class_var(("value2",)).equals(GrandchildState.value2)
    assert TestState.get_class_var(("child_state", "value")).equals(ChildState.value)
    assert TestState.get_class_var(
        ("child_state", "grandchild_state", "value2")
    ).equals(
        GrandchildState.value2,
    )
    assert ChildState.get_class_var(("grandchild_state", "value2")).equals(
        GrandchildState.value2,
    )
    with pytest.raises(ValueError):
        TestState.get_class_var(("invalid_var",))
    with pytest.raises(ValueError):
        TestState.get_class_var(
            (
                "child_state",
                "invalid_var",
            )
        )


def test_set_class_var():
    """Test setting the var of a class."""
    with pytest.raises(AttributeError):
        TestState.num3  # type: ignore
    TestState._set_var(BaseVar(name="num3", type_=int).set_state(TestState))
    var = TestState.num3  # type: ignore
    assert var.name == "num3"
    assert var.type_ == int
    assert var.state == TestState.get_full_name()


def test_set_parent_and_substates(test_state, child_state, grandchild_state):
    """Test setting the parent and substates.

    Args:
        test_state: A state.
        child_state: A child state.
        grandchild_state: A grandchild state.
    """
    assert len(test_state.substates) == 2
    assert set(test_state.substates) == {"child_state", "child_state2"}

    assert child_state.parent_state == test_state
    assert len(child_state.substates) == 1
    assert set(child_state.substates) == {"grandchild_state"}

    assert grandchild_state.parent_state == child_state
    assert len(grandchild_state.substates) == 0


def test_get_child_attribute(test_state, child_state, child_state2, grandchild_state):
    """Test getting the attribute of a state.

    Args:
        test_state: A state.
        child_state: A child state.
        child_state2: A child state.
        grandchild_state: A grandchild state.
    """
    assert test_state.num1 == 0
    assert child_state.value == ""
    assert child_state2.value == ""
    assert child_state.count == 23
    assert grandchild_state.value2 == ""
    with pytest.raises(AttributeError):
        test_state.invalid
    with pytest.raises(AttributeError):
        test_state.child_state.invalid
    with pytest.raises(AttributeError):
        test_state.child_state.grandchild_state.invalid


def test_set_child_attribute(test_state, child_state, grandchild_state):
    """Test setting the attribute of a state.

    Args:
        test_state: A state.
        child_state: A child state.
        grandchild_state: A grandchild state.
    """
    test_state.num1 = 10
    assert test_state.num1 == 10
    assert child_state.num1 == 10
    assert grandchild_state.num1 == 10

    grandchild_state.num1 = 5
    assert test_state.num1 == 5
    assert child_state.num1 == 5
    assert grandchild_state.num1 == 5

    child_state.value = "test"
    assert child_state.value == "test"
    assert grandchild_state.value == "test"

    grandchild_state.value = "test2"
    assert child_state.value == "test2"
    assert grandchild_state.value == "test2"

    grandchild_state.value2 = "test3"
    assert grandchild_state.value2 == "test3"


def test_get_substate(test_state, child_state, child_state2, grandchild_state):
    """Test getting the substate of a state.

    Args:
        test_state: A state.
        child_state: A child state.
        child_state2: A child state.
        grandchild_state: A grandchild state.
    """
    assert test_state.get_substate(("child_state",)) == child_state
    assert test_state.get_substate(("child_state2",)) == child_state2
    assert (
        test_state.get_substate(("child_state", "grandchild_state")) == grandchild_state
    )
    assert child_state.get_substate(("grandchild_state",)) == grandchild_state
    with pytest.raises(ValueError):
        test_state.get_substate(("invalid",))
    with pytest.raises(ValueError):
        test_state.get_substate(("child_state", "invalid"))
    with pytest.raises(ValueError):
        test_state.get_substate(("child_state", "grandchild_state", "invalid"))


def test_set_dirty_var(test_state):
    """Test changing state vars marks the value as dirty.

    Args:
        test_state: A state.
    """
    # Initially there should be no dirty vars.
    assert test_state.dirty_vars == set()

    # Setting a var should mark it as dirty.
    test_state.num1 = 1
    assert test_state.dirty_vars == {"num1", "sum"}

    # Setting another var should mark it as dirty.
    test_state.num2 = 2
    assert test_state.dirty_vars == {"num1", "num2", "sum"}

    # Cleaning the state should remove all dirty vars.
    test_state._clean()
    assert test_state.dirty_vars == set()


def test_set_dirty_substate(test_state, child_state, child_state2, grandchild_state):
    """Test changing substate vars marks the value as dirty.

    Args:
        test_state: A state.
        child_state: A child state.
        child_state2: A child state.
        grandchild_state: A grandchild state.
    """
    # Initially there should be no dirty vars.
    assert test_state.dirty_vars == set()
    assert child_state.dirty_vars == set()
    assert child_state2.dirty_vars == set()
    assert grandchild_state.dirty_vars == set()

    # Setting a var should mark it as dirty.
    child_state.value = "test"
    assert child_state.dirty_vars == {"value"}
    assert test_state.dirty_substates == {"child_state"}
    assert child_state.dirty_substates == set()

    # Cleaning the parent state should remove the dirty substate.
    test_state._clean()
    assert test_state.dirty_substates == set()
    assert child_state.dirty_vars == set()

    # Setting a var on the grandchild should bubble up.
    grandchild_state.value2 = "test2"
    assert child_state.dirty_substates == {"grandchild_state"}
    assert test_state.dirty_substates == {"child_state"}

    # Cleaning the middle state should keep the parent state dirty.
    child_state._clean()
    assert test_state.dirty_substates == {"child_state"}
    assert child_state.dirty_substates == set()
    assert grandchild_state.dirty_vars == set()


def test_reset(test_state, child_state):
    """Test resetting the state.

    Args:
        test_state: A state.
        child_state: A child state.
    """
    # Set some values.
    test_state.num1 = 1
    test_state.num2 = 2
    child_state.value = "test"

    # Reset the state.
    test_state.reset()

    # The values should be reset.
    assert test_state.num1 == 0
    assert test_state.num2 == 3.14
    assert child_state.value == ""

    expected_dirty_vars = {
        "num1",
        "num2",
        "obj",
        "upper",
        "complex",
        "is_hydrated",
        "fig",
        "key",
        "sum",
        "array",
        "map_key",
        "mapping",
        "dt",
    }

    # The dirty vars should be reset.
    assert test_state.dirty_vars == expected_dirty_vars
    assert child_state.dirty_vars == {"count", "value"}

    # The dirty substates should be reset.
    assert test_state.dirty_substates == {"child_state", "child_state2"}


@pytest.mark.asyncio
async def test_process_event_simple(test_state):
    """Test processing an event.

    Args:
        test_state: A state.
    """
    assert test_state.num1 == 0

    event = Event(token="t", name="set_num1", payload={"value": 69})
    update = await test_state._process(event).__anext__()

    # The event should update the value.
    assert test_state.num1 == 69

    # The delta should contain the changes, including computed vars.
    # assert update.delta == {"test_state": {"num1": 69, "sum": 72.14}}
    assert update.delta == {"test_state": {"num1": 69, "sum": 72.14, "upper": ""}}
    assert update.events == []


@pytest.mark.asyncio
async def test_process_event_substate(test_state, child_state, grandchild_state):
    """Test processing an event on a substate.

    Args:
        test_state: A state.
        child_state: A child state.
        grandchild_state: A grandchild state.
    """
    # Events should bubble down to the substate.
    assert child_state.value == ""
    assert child_state.count == 23
    event = Event(
        token="t", name="child_state.change_both", payload={"value": "hi", "count": 12}
    )
    update = await test_state._process(event).__anext__()
    assert child_state.value == "HI"
    assert child_state.count == 24
    assert update.delta == {
        "test_state": {"sum": 3.14, "upper": ""},
        "test_state.child_state": {"value": "HI", "count": 24},
    }
    test_state._clean()

    # Test with the granchild state.
    assert grandchild_state.value2 == ""
    event = Event(
        token="t",
        name="child_state.grandchild_state.set_value2",
        payload={"value": "new"},
    )
    update = await test_state._process(event).__anext__()
    assert grandchild_state.value2 == "new"
    assert update.delta == {
        "test_state": {"sum": 3.14, "upper": ""},
        "test_state.child_state.grandchild_state": {"value2": "new"},
    }


@pytest.mark.asyncio
async def test_process_event_generator():
    """Test event handlers that generate multiple updates."""
    gen_state = GenState()  # type: ignore
    event = Event(
        token="t",
        name="go",
        payload={"c": 5},
    )
    gen = gen_state._process(event)

    count = 0
    async for update in gen:
        count += 1
        if count == 6:
            assert update.delta == {}
            assert update.final
        else:
            assert gen_state.value == count
            assert update.delta == {
                "gen_state": {"value": count},
            }
            assert not update.final

    assert count == 6


def test_get_token(test_state, mocker, router_data):
    """Test that the token obtained from the router_data is correct.

    Args:
        test_state: The test state.
        mocker: Pytest Mocker object.
        router_data: The router data fixture.
    """
    mocker.patch.object(test_state, "router_data", router_data)

    assert test_state.get_token() == "b181904c-3953-4a79-dc18-ae9518c22f05"


def test_get_sid(test_state, mocker, router_data):
    """Test getting session id.

    Args:
        test_state: A state.
        mocker: Pytest Mocker object.
        router_data: The router data fixture.
    """
    mocker.patch.object(test_state, "router_data", router_data)

    assert test_state.get_sid() == "9fpxSzPb9aFMb4wFAAAH"


def test_get_headers(test_state, mocker, router_data, router_data_headers):
    """Test getting client headers.

    Args:
        test_state: A state.
        mocker: Pytest Mocker object.
        router_data: The router data fixture.
        router_data_headers: The expected headers.
    """
    mocker.patch.object(test_state, "router_data", router_data)

    assert test_state.get_headers() == router_data_headers


def test_get_client_ip(test_state, mocker, router_data):
    """Test getting client IP.

    Args:
        test_state: A state.
        mocker: Pytest Mocker object.
        router_data: The router data fixture.
    """
    mocker.patch.object(test_state, "router_data", router_data)

    assert test_state.get_client_ip() == "127.0.0.1"


def test_get_cookies(test_state, mocker, router_data):
    """Test getting client cookies.

    Args:
        test_state: A state.
        mocker: Pytest Mocker object.
        router_data: The router data fixture.
    """
    mocker.patch.object(test_state, "router_data", router_data)

    assert test_state.get_cookies() == {
        "csrftoken": "mocktoken",
        "name": "reflex",
        "list_cookies": ["some", "random", "cookies"],
        "dict_cookies": {"name": "reflex"},
        "val": True,
    }


def test_get_current_page(test_state):
    assert test_state.get_current_page() == ""

    route = "mypage/subpage"
    test_state.router_data = {RouteVar.PATH: route}

    assert test_state.get_current_page() == route


def test_get_query_params(test_state):
    assert test_state.get_query_params() == {}

    params = {"p1": "a", "p2": "b"}
    test_state.router_data = {RouteVar.QUERY: params}

    assert test_state.get_query_params() == params


def test_add_var():
    class DynamicState(State):
        pass

    ds1 = DynamicState()
    assert "dynamic_int" not in ds1.__dict__
    assert not hasattr(ds1, "dynamic_int")
    ds1.add_var("dynamic_int", int, 42)
    # Existing instances get the BaseVar
    assert ds1.dynamic_int.equals(DynamicState.dynamic_int)  # type: ignore
    # New instances get an actual value with the default
    assert DynamicState().dynamic_int == 42

    ds1.add_var("dynamic_list", List[int], [5, 10])
    assert ds1.dynamic_list.equals(DynamicState.dynamic_list)  # type: ignore
    ds2 = DynamicState()
    assert ds2.dynamic_list == [5, 10]
    ds2.dynamic_list.append(15)
    assert ds2.dynamic_list == [5, 10, 15]
    assert DynamicState().dynamic_list == [5, 10]

    ds1.add_var("dynamic_dict", Dict[str, int], {"k1": 5, "k2": 10})
    assert ds1.dynamic_dict.equals(DynamicState.dynamic_dict)  # type: ignore
    assert ds2.dynamic_dict.equals(DynamicState.dynamic_dict)  # type: ignore
    assert DynamicState().dynamic_dict == {"k1": 5, "k2": 10}
    assert DynamicState().dynamic_dict == {"k1": 5, "k2": 10}


def test_add_var_default_handlers(test_state):
    test_state.add_var("rand_int", int, 10)
    assert "set_rand_int" in test_state.event_handlers
    assert isinstance(test_state.event_handlers["set_rand_int"], EventHandler)


class InterdependentState(State):
    """A state with 3 vars and 3 computed vars.

    x: a variable that no computed var depends on
    v1: a varable that one computed var directly depeneds on
    _v2: a backend variable that one computed var directly depends on

    v1x2: a computed var that depends on v1
    v2x2: a computed var that depends on backend var _v2
    v1x2x2: a computed var that depends on computed var v1x2
    """

    x: int = 0
    v1: int = 0
    _v2: int = 1

    @rx.cached_var
    def v1x2(self) -> int:
        """Depends on var v1.

        Returns:
            Var v1 multiplied by 2
        """
        return self.v1 * 2

    @rx.cached_var
    def v2x2(self) -> int:
        """Depends on backend var _v2.

        Returns:
            backend var _v2 multiplied by 2
        """
        return self._v2 * 2

    @rx.cached_var
    def v1x2x2(self) -> int:
        """Depends on ComputedVar v1x2.

        Returns:
            ComputedVar v1x2 multiplied by 2
        """
        return self.v1x2 * 2


@pytest.fixture
def interdependent_state() -> State:
    """A state with varying dependency between vars.

    Returns:
        instance of InterdependentState
    """
    s = InterdependentState()
    s.dict()  # prime initial relationships by accessing all ComputedVars
    return s


def test_not_dirty_computed_var_from_var(interdependent_state):
    """Set Var that no ComputedVar depends on, expect no recalculation.

    Args:
        interdependent_state: A state with varying Var dependencies.
    """
    interdependent_state.x = 5
    assert interdependent_state.get_delta() == {
        interdependent_state.get_full_name(): {"x": 5},
    }


def test_dirty_computed_var_from_var(interdependent_state):
    """Set Var that ComputedVar depends on, expect recalculation.

    The other ComputedVar depends on the changed ComputedVar and should also be
    recalculated. No other ComputedVars should be recalculated.

    Args:
        interdependent_state: A state with varying Var dependencies.
    """
    interdependent_state.v1 = 1
    assert interdependent_state.get_delta() == {
        interdependent_state.get_full_name(): {"v1": 1, "v1x2": 2, "v1x2x2": 4},
    }


def test_dirty_computed_var_from_backend_var(interdependent_state):
    """Set backend var that ComputedVar depends on, expect recalculation.

    Args:
        interdependent_state: A state with varying Var dependencies.
    """
    interdependent_state._v2 = 2
    assert interdependent_state.get_delta() == {
        interdependent_state.get_full_name(): {"v2x2": 4},
    }


def test_per_state_backend_var(interdependent_state):
    """Set backend var on one instance, expect no affect in other instances.

    Args:
        interdependent_state: A state with varying Var dependencies.
    """
    s2 = InterdependentState()
    assert s2._v2 == interdependent_state._v2
    interdependent_state._v2 = 2
    assert s2._v2 != interdependent_state._v2
    s3 = InterdependentState()
    assert s3._v2 != interdependent_state._v2
    # both s2 and s3 should still have the default value
    assert s2._v2 == s3._v2
    # changing s2._v2 should not affect others
    s2._v2 = 4
    assert s2._v2 != interdependent_state._v2
    assert s2._v2 != s3._v2


def test_child_state():
    """Test that the child state computed vars can reference parent state vars."""

    class MainState(State):
        v: int = 2

    class ChildState(MainState):
        @ComputedVar
        def rendered_var(self):
            return self.v

    ms = MainState()
    cs = ms.substates[ChildState.get_name()]
    assert ms.v == 2
    assert cs.v == 2
    assert cs.rendered_var == 2


def test_conditional_computed_vars():
    """Test that computed vars can have conditionals."""

    class MainState(State):
        flag: bool = False
        t1: str = "a"
        t2: str = "b"

        @ComputedVar
        def rendered_var(self) -> str:
            if self.flag:
                return self.t1
            return self.t2

    ms = MainState()
    # Initially there are no dirty computed vars.
    assert ms._dirty_computed_vars(from_vars={"flag"}) == {"rendered_var"}
    assert ms._dirty_computed_vars(from_vars={"t2"}) == {"rendered_var"}
    assert ms._dirty_computed_vars(from_vars={"t1"}) == {"rendered_var"}
    assert ms.computed_vars["rendered_var"].deps(objclass=MainState) == {
        "flag",
        "t1",
        "t2",
    }


def test_event_handlers_convert_to_fns(test_state, child_state):
    """Test that when the state is initialized, event handlers are converted to fns.

    Args:
        test_state: A state with event handlers.
        child_state: A child state with event handlers.
    """
    # The class instances should be event handlers.
    assert isinstance(TestState.do_something, EventHandler)
    assert isinstance(ChildState.change_both, EventHandler)

    # The object instances should be fns.
    test_state.do_something()

    child_state.change_both(value="goose", count=9)
    assert child_state.value == "GOOSE"
    assert child_state.count == 18


def test_event_handlers_call_other_handlers():
    """Test that event handlers can call other event handlers."""

    class MainState(State):
        v: int = 0

        def set_v(self, v: int):
            self.v = v

        def set_v2(self, v: int):
            self.set_v(v)

    class SubState(MainState):
        def set_v3(self, v: int):
            self.set_v2(v)

    ms = MainState()
    ms.set_v2(1)
    assert ms.v == 1

    # ensure handler can be called from substate
    ms.substates[SubState.get_name()].set_v3(2)
    assert ms.v == 2


def test_computed_var_cached():
    """Test that a ComputedVar doesn't recalculate when accessed."""
    comp_v_calls = 0

    class ComputedState(State):
        v: int = 0

        @rx.cached_var
        def comp_v(self) -> int:
            nonlocal comp_v_calls
            comp_v_calls += 1
            return self.v

    cs = ComputedState()
    assert cs.dict()["v"] == 0
    assert comp_v_calls == 1
    assert cs.dict()["comp_v"] == 0
    assert comp_v_calls == 1
    assert cs.comp_v == 0
    assert comp_v_calls == 1
    cs.v = 1
    assert comp_v_calls == 1
    assert cs.comp_v == 1
    assert comp_v_calls == 2


def test_computed_var_cached_depends_on_non_cached():
    """Test that a cached_var is recalculated if it depends on non-cached ComputedVar."""

    class ComputedState(State):
        v: int = 0

        @rx.var
        def no_cache_v(self) -> int:
            return self.v

        @rx.cached_var
        def dep_v(self) -> int:
            return self.no_cache_v

        @rx.cached_var
        def comp_v(self) -> int:
            return self.v

    cs = ComputedState()
    assert cs.dirty_vars == set()
    assert cs.get_delta() == {cs.get_name(): {"no_cache_v": 0, "dep_v": 0}}
    cs._clean()
    assert cs.dirty_vars == set()
    assert cs.get_delta() == {cs.get_name(): {"no_cache_v": 0, "dep_v": 0}}
    cs._clean()
    assert cs.dirty_vars == set()
    cs.v = 1
    assert cs.dirty_vars == {"v", "comp_v", "dep_v", "no_cache_v"}
    assert cs.get_delta() == {
        cs.get_name(): {"v": 1, "no_cache_v": 1, "dep_v": 1, "comp_v": 1}
    }
    cs._clean()
    assert cs.dirty_vars == set()
    assert cs.get_delta() == {cs.get_name(): {"no_cache_v": 1, "dep_v": 1}}
    cs._clean()
    assert cs.dirty_vars == set()
    assert cs.get_delta() == {cs.get_name(): {"no_cache_v": 1, "dep_v": 1}}
    cs._clean()
    assert cs.dirty_vars == set()


def test_computed_var_depends_on_parent_non_cached():
    """Child state cached_var that depends on parent state un cached var is always recalculated."""
    counter = 0

    class ParentState(State):
        @rx.var
        def no_cache_v(self) -> int:
            nonlocal counter
            counter += 1
            return counter

    class ChildState(ParentState):
        @rx.cached_var
        def dep_v(self) -> int:
            return self.no_cache_v

    ps = ParentState()
    cs = ps.substates[ChildState.get_name()]

    assert ps.dirty_vars == set()
    assert cs.dirty_vars == set()

    assert ps.dict() == {
        cs.get_name(): {"dep_v": 2},
        "no_cache_v": 1,
        CompileVars.IS_HYDRATED: False,
    }
    assert ps.dict() == {
        cs.get_name(): {"dep_v": 4},
        "no_cache_v": 3,
        CompileVars.IS_HYDRATED: False,
    }
    assert ps.dict() == {
        cs.get_name(): {"dep_v": 6},
        "no_cache_v": 5,
        CompileVars.IS_HYDRATED: False,
    }
    assert counter == 6


@pytest.mark.parametrize("use_partial", [True, False])
def test_cached_var_depends_on_event_handler(use_partial: bool):
    """A cached_var that calls an event handler calculates deps correctly.

    Args:
        use_partial: if true, replace the EventHandler with functools.partial
    """
    counter = 0

    class HandlerState(State):
        x: int = 42

        def handler(self):
            self.x = self.x + 1

        @rx.cached_var
        def cached_x_side_effect(self) -> int:
            self.handler()
            nonlocal counter
            counter += 1
            return counter

    if use_partial:
        HandlerState.handler = functools.partial(HandlerState.handler.fn)
        assert isinstance(HandlerState.handler, functools.partial)
    else:
        assert isinstance(HandlerState.handler, EventHandler)

    s = HandlerState()
    assert "cached_x_side_effect" in s.computed_var_dependencies["x"]
    assert s.cached_x_side_effect == 1
    assert s.x == 43
    s.handler()
    assert s.cached_x_side_effect == 2
    assert s.x == 45


def test_computed_var_dependencies():
    """Test that a ComputedVar correctly tracks its dependencies."""

    class ComputedState(State):
        v: int = 0
        w: int = 0
        x: int = 0
        y: List[int] = [1, 2, 3]
        _z: List[int] = [1, 2, 3]

        @rx.cached_var
        def comp_v(self) -> int:
            """Direct access.

            Returns:
                The value of self.v.
            """
            return self.v

        @rx.cached_var
        def comp_w(self):
            """Nested lambda.

            Returns:
                A lambda that returns the value of self.w.
            """
            return lambda: self.w

        @rx.cached_var
        def comp_x(self):
            """Nested function.

            Returns:
                A function that returns the value of self.x.
            """

            def _():
                return self.x

            return _

        @rx.cached_var
        def comp_y(self) -> List[int]:
            """Comprehension iterating over attribute.

            Returns:
                A list of the values of self.y.
            """
            return [round(y) for y in self.y]

        @rx.cached_var
        def comp_z(self) -> List[bool]:
            """Comprehension accesses attribute.

            Returns:
                A list of whether the values 0-4 are in self._z.
            """
            return [z in self._z for z in range(5)]

    cs = ComputedState()
    assert cs.computed_var_dependencies["v"] == {"comp_v"}
    assert cs.computed_var_dependencies["w"] == {"comp_w"}
    assert cs.computed_var_dependencies["x"] == {"comp_x"}
    assert cs.computed_var_dependencies["y"] == {"comp_y"}
    assert cs.computed_var_dependencies["_z"] == {"comp_z"}


def test_backend_method():
    """A method with leading underscore should be callable from event handler."""

    class BackendMethodState(State):
        def _be_method(self):
            return True

        def handler(self):
            assert self._be_method()

    bms = BackendMethodState()
    bms.handler()
    assert bms._be_method()


def test_setattr_of_mutable_types(mutable_state):
    """Test that mutable types are converted to corresponding Reflex wrappers.

    Args:
        mutable_state: A test state.
    """
    array = mutable_state.array
    hashmap = mutable_state.hashmap
    test_set = mutable_state.test_set

    assert isinstance(array, MutableProxy)
    assert isinstance(array, list)
    assert isinstance(array[1], MutableProxy)
    assert isinstance(array[1], list)
    assert isinstance(array[2], MutableProxy)
    assert isinstance(array[2], dict)

    assert isinstance(hashmap, MutableProxy)
    assert isinstance(hashmap, dict)
    assert isinstance(hashmap["key"], MutableProxy)
    assert isinstance(hashmap["key"], list)
    assert isinstance(hashmap["third_key"], MutableProxy)
    assert isinstance(hashmap["third_key"], dict)

    assert isinstance(test_set, MutableProxy)
    assert isinstance(test_set, set)

    assert isinstance(mutable_state.custom, MutableProxy)
    assert isinstance(mutable_state.custom.array, MutableProxy)
    assert isinstance(mutable_state.custom.array, list)
    assert isinstance(mutable_state.custom.hashmap, MutableProxy)
    assert isinstance(mutable_state.custom.hashmap, dict)
    assert isinstance(mutable_state.custom.test_set, MutableProxy)
    assert isinstance(mutable_state.custom.test_set, set)
    assert isinstance(mutable_state.custom.custom, MutableProxy)

    mutable_state.reassign_mutables()

    array = mutable_state.array
    hashmap = mutable_state.hashmap
    test_set = mutable_state.test_set

    assert isinstance(array, MutableProxy)
    assert isinstance(array, list)
    assert isinstance(array[1], MutableProxy)
    assert isinstance(array[1], list)
    assert isinstance(array[2], MutableProxy)
    assert isinstance(array[2], dict)

    assert isinstance(hashmap, MutableProxy)
    assert isinstance(hashmap, dict)
    assert isinstance(hashmap["mod_key"], MutableProxy)
    assert isinstance(hashmap["mod_key"], list)
    assert isinstance(hashmap["mod_third_key"], MutableProxy)
    assert isinstance(hashmap["mod_third_key"], dict)

    assert isinstance(test_set, MutableProxy)
    assert isinstance(test_set, set)


def test_error_on_state_method_shadow():
    """Test that an error is thrown when an event handler shadows a state method."""
    with pytest.raises(NameError) as err:

        class InvalidTest(rx.State):
            def reset(self):
                pass

    assert (
        err.value.args[0]
        == f"The event handler name `reset` shadows a builtin State method; use a different name instead"
    )


def test_state_with_invalid_yield():
    """Test that an error is thrown when a state yields an invalid value."""

    class StateWithInvalidYield(rx.State):
        """A state that yields an invalid value."""

        def invalid_handler(self):
            """Invalid handler.

            Yields:
                an invalid value.
            """
            yield 1

    invalid_state = StateWithInvalidYield()
    with pytest.raises(TypeError) as err:
        invalid_state._check_valid(
            invalid_state.event_handlers["invalid_handler"],
            rx.event.Event(token="fake_token", name="invalid_handler"),
        )
    assert (
        "must only return/yield: None, Events or other EventHandlers"
        in err.value.args[0]
    )


@pytest.fixture(scope="function", params=["in_process", "redis"])
def state_manager(request) -> Generator[StateManager, None, None]:
    """Instance of state manager parametrized for redis and in-process.

    Args:
        request: pytest request object.

    Yields:
        A state manager instance
    """
    state_manager = StateManager.create(state=TestState)
    if request.param == "redis":
        if not isinstance(state_manager, StateManagerRedis):
            pytest.skip("Test requires redis")
    else:
        # explicitly NOT using redis
        state_manager = StateManagerMemory(state=TestState)
        assert not state_manager._states_locks

    yield state_manager

    if isinstance(state_manager, StateManagerRedis):
        asyncio.get_event_loop().run_until_complete(state_manager.redis.close())


@pytest.mark.asyncio
async def test_state_manager_modify_state(state_manager: StateManager, token: str):
    """Test that the state manager can modify a state exclusively.

    Args:
        state_manager: A state manager instance.
        token: A token.
    """
    async with state_manager.modify_state(token):
        if isinstance(state_manager, StateManagerRedis):
            assert await state_manager.redis.get(f"{token}_lock")
        elif isinstance(state_manager, StateManagerMemory):
            assert token in state_manager._states_locks
            assert state_manager._states_locks[token].locked()
    # lock should be dropped after exiting the context
    if isinstance(state_manager, StateManagerRedis):
        assert (await state_manager.redis.get(f"{token}_lock")) is None
    elif isinstance(state_manager, StateManagerMemory):
        assert not state_manager._states_locks[token].locked()

        # separate instances should NOT share locks
        sm2 = StateManagerMemory(state=TestState)
        assert sm2._state_manager_lock is state_manager._state_manager_lock
        assert not sm2._states_locks
        if state_manager._states_locks:
            assert sm2._states_locks != state_manager._states_locks


@pytest.mark.asyncio
async def test_state_manager_contend(state_manager: StateManager, token: str):
    """Multiple coroutines attempting to access the same state.

    Args:
        state_manager: A state manager instance.
        token: A token.
    """
    n_coroutines = 10
    exp_num1 = 10

    async with state_manager.modify_state(token) as state:
        state.num1 = 0

    async def _coro():
        async with state_manager.modify_state(token) as state:
            await asyncio.sleep(0.01)
            state.num1 += 1

    tasks = [asyncio.create_task(_coro()) for _ in range(n_coroutines)]

    for f in asyncio.as_completed(tasks):
        await f

    assert (await state_manager.get_state(token)).num1 == exp_num1

    if isinstance(state_manager, StateManagerRedis):
        assert (await state_manager.redis.get(f"{token}_lock")) is None
    elif isinstance(state_manager, StateManagerMemory):
        assert token in state_manager._states_locks
        assert not state_manager._states_locks[token].locked()


@pytest.fixture(scope="function")
def state_manager_redis() -> Generator[StateManager, None, None]:
    """Instance of state manager for redis only.

    Yields:
        A state manager instance
    """
    state_manager = StateManager.create(TestState)

    if not isinstance(state_manager, StateManagerRedis):
        pytest.skip("Test requires redis")

    yield state_manager

    asyncio.get_event_loop().run_until_complete(state_manager.redis.close())


@pytest.mark.asyncio
async def test_state_manager_lock_expire(state_manager_redis: StateManager, token: str):
    """Test that the state manager lock expires and raises exception exiting context.

    Args:
        state_manager_redis: A state manager instance.
        token: A token.
    """
    state_manager_redis.lock_expiration = LOCK_EXPIRATION

    async with state_manager_redis.modify_state(token):
        await asyncio.sleep(0.01)

    with pytest.raises(LockExpiredError):
        async with state_manager_redis.modify_state(token):
            await asyncio.sleep(LOCK_EXPIRE_SLEEP)


@pytest.mark.asyncio
async def test_state_manager_lock_expire_contend(
    state_manager_redis: StateManager, token: str
):
    """Test that the state manager lock expires and queued waiters proceed.

    Args:
        state_manager_redis: A state manager instance.
        token: A token.
    """
    exp_num1 = 4252
    unexp_num1 = 666

    state_manager_redis.lock_expiration = LOCK_EXPIRATION

    order = []

    async def _coro_blocker():
        async with state_manager_redis.modify_state(token) as state:
            order.append("blocker")
            await asyncio.sleep(LOCK_EXPIRE_SLEEP)
            state.num1 = unexp_num1

    async def _coro_waiter():
        while "blocker" not in order:
            await asyncio.sleep(0.005)
        async with state_manager_redis.modify_state(token) as state:
            order.append("waiter")
            assert state.num1 != unexp_num1
            state.num1 = exp_num1

    tasks = [
        asyncio.create_task(_coro_blocker()),
        asyncio.create_task(_coro_waiter()),
    ]
    with pytest.raises(LockExpiredError):
        await tasks[0]
    await tasks[1]

    assert order == ["blocker", "waiter"]
    assert (await state_manager_redis.get_state(token)).num1 == exp_num1


@pytest.fixture(scope="function")
def mock_app(monkeypatch, app: rx.App, state_manager: StateManager) -> rx.App:
    """Mock app fixture.

    Args:
        monkeypatch: Pytest monkeypatch object.
        app: An app.
        state_manager: A state manager.

    Returns:
        The app, after mocking out prerequisites.get_app()
    """
    app_module = Mock()
    setattr(app_module, CompileVars.APP, app)
    app.state = TestState
    app.state_manager = state_manager
    assert app.event_namespace is not None
    app.event_namespace.emit = AsyncMock()
    monkeypatch.setattr(prerequisites, "get_app", lambda: app_module)
    return app


@pytest.mark.asyncio
async def test_state_proxy(grandchild_state: GrandchildState, mock_app: rx.App):
    """Test that the state proxy works.

    Args:
        grandchild_state: A grandchild state.
        mock_app: An app that will be returned by `get_app()`
    """
    child_state = grandchild_state.parent_state
    assert child_state is not None
    parent_state = child_state.parent_state
    assert parent_state is not None
    if isinstance(mock_app.state_manager, StateManagerMemory):
        mock_app.state_manager.states[parent_state.get_token()] = parent_state

    sp = StateProxy(grandchild_state)
    assert sp.__wrapped__ == grandchild_state
    assert sp._self_substate_path == grandchild_state.get_full_name().split(".")
    assert sp._self_app is mock_app
    assert not sp._self_mutable
    assert sp._self_actx is None

    # cannot use normal contextmanager protocol
    with pytest.raises(TypeError), sp:
        pass

    with pytest.raises(ImmutableStateError):
        # cannot directly modify state proxy outside of async context
        sp.value2 = 16

    async with sp:
        assert sp._self_actx is not None
        assert sp._self_mutable  # proxy is mutable inside context
        if isinstance(mock_app.state_manager, StateManagerMemory):
            # For in-process store, only one instance of the state exists
            assert sp.__wrapped__ is grandchild_state
        else:
            # When redis is used, a new+updated instance is assigned to the proxy
            assert sp.__wrapped__ is not grandchild_state
        sp.value2 = 42
    assert not sp._self_mutable  # proxy is not mutable after exiting context
    assert sp._self_actx is None
    assert sp.value2 == 42

    # Get the state from the state manager directly and check that the value is updated
    gotten_state = await mock_app.state_manager.get_state(grandchild_state.get_token())
    if isinstance(mock_app.state_manager, StateManagerMemory):
        # For in-process store, only one instance of the state exists
        assert gotten_state is parent_state
    else:
        assert gotten_state is not parent_state
    gotten_grandchild_state = gotten_state.get_substate(sp._self_substate_path)
    assert gotten_grandchild_state is not None
    assert gotten_grandchild_state.value2 == 42

    # ensure state update was emitted
    assert mock_app.event_namespace is not None
    mock_app.event_namespace.emit.assert_called_once()
    mcall = mock_app.event_namespace.emit.mock_calls[0]
    assert mcall.args[0] == str(SocketEvent.EVENT)
    assert json.loads(mcall.args[1]) == StateUpdate(
        delta={
            parent_state.get_full_name(): {
                "upper": "",
                "sum": 3.14,
            },
            grandchild_state.get_full_name(): {
                "value2": 42,
            },
        }
    )
    assert mcall.kwargs["to"] == grandchild_state.get_sid()


class BackgroundTaskState(State):
    """A state with a background task."""

    order: List[str] = []
    dict_list: Dict[str, List[int]] = {"foo": []}

    @rx.background
    async def background_task(self):
        """A background task that updates the state."""
        async with self:
            assert not self.order
            self.order.append("background_task:start")

        assert isinstance(self, StateProxy)
        with pytest.raises(ImmutableStateError):
            self.order.append("bad idea")

        with pytest.raises(ImmutableStateError):
            # Even nested access to mutables raises an exception.
            self.dict_list["foo"].append(42)

        with pytest.raises(ImmutableStateError):
            # Direct calling another handler that modifies state raises an exception.
            self.other()

        with pytest.raises(ImmutableStateError):
            # Calling other methods that modify state raises an exception.
            self._private_method()

        # wait for some other event to happen
        while len(self.order) == 1:
            await asyncio.sleep(0.01)
            async with self:
                pass  # update proxy instance

        async with self:
            self.order.append("background_task:stop")
            self.other()  # direct calling event handlers works in context
            self._private_method()

    @rx.background
    async def background_task_reset(self):
        """A background task that resets the state."""
        with pytest.raises(ImmutableStateError):
            # Resetting the state should be explicitly blocked.
            self.reset()

        async with self:
            self.order.append("foo")
            self.reset()
        assert not self.order
        async with self:
            self.order.append("reset")

    @rx.background
    async def background_task_generator(self):
        """A background task generator that does nothing.

        Yields:
            None
        """
        yield

    def other(self):
        """Some other event that updates the state."""
        self.order.append("other")

    def _private_method(self):
        """Some private method that updates the state."""
        self.order.append("private")

    async def bad_chain1(self):
        """Test that a background task cannot be chained."""
        await self.background_task()

    async def bad_chain2(self):
        """Test that a background task generator cannot be chained."""
        async for _foo in self.background_task_generator():
            pass


@pytest.mark.asyncio
async def test_background_task_no_block(mock_app: rx.App, token: str):
    """Test that a background task does not block other events.

    Args:
        mock_app: An app that will be returned by `get_app()`
        token: A token.
    """
    router_data = {"query": {}}
    mock_app.state_manager.state = mock_app.state = BackgroundTaskState
    async for update in rx.app.process(  # type: ignore
        mock_app,
        Event(
            token=token,
            name=f"{BackgroundTaskState.get_name()}.background_task",
            router_data=router_data,
            payload={},
        ),
        sid="",
        headers={},
        client_ip="",
    ):
        # background task returns empty update immediately
        assert update == StateUpdate()

    # wait for the coroutine to start
    await asyncio.sleep(0.5 if CI else 0.1)
    assert len(mock_app.background_tasks) == 1

    # Process another normal event
    async for update in rx.app.process(  # type: ignore
        mock_app,
        Event(
            token=token,
            name=f"{BackgroundTaskState.get_name()}.other",
            router_data=router_data,
            payload={},
        ),
        sid="",
        headers={},
        client_ip="",
    ):
        # other task returns delta
        assert update == StateUpdate(
            delta={
                BackgroundTaskState.get_name(): {
                    "order": [
                        "background_task:start",
                        "other",
                    ],
                }
            }
        )

    # Explicit wait for background tasks
    for task in tuple(mock_app.background_tasks):
        await task
    assert not mock_app.background_tasks

    assert (await mock_app.state_manager.get_state(token)).order == [
        "background_task:start",
        "other",
        "background_task:stop",
        "other",
        "private",
    ]


@pytest.mark.asyncio
async def test_background_task_reset(mock_app: rx.App, token: str):
    """Test that a background task calling reset is protected by the state proxy.

    Args:
        mock_app: An app that will be returned by `get_app()`
        token: A token.
    """
    router_data = {"query": {}}
    mock_app.state_manager.state = mock_app.state = BackgroundTaskState
    async for update in rx.app.process(  # type: ignore
        mock_app,
        Event(
            token=token,
            name=f"{BackgroundTaskState.get_name()}.background_task_reset",
            router_data=router_data,
            payload={},
        ),
        sid="",
        headers={},
        client_ip="",
    ):
        # background task returns empty update immediately
        assert update == StateUpdate()

    # Explicit wait for background tasks
    for task in tuple(mock_app.background_tasks):
        await task
    assert not mock_app.background_tasks

    assert (await mock_app.state_manager.get_state(token)).order == [
        "reset",
    ]


@pytest.mark.asyncio
async def test_background_task_no_chain():
    """Test that a background task cannot be chained."""
    bts = BackgroundTaskState()
    with pytest.raises(RuntimeError):
        await bts.bad_chain1()
    with pytest.raises(RuntimeError):
        await bts.bad_chain2()


def test_mutable_list(mutable_state):
    """Test that mutable lists are tracked correctly.

    Args:
        mutable_state: A test state.
    """
    assert not mutable_state.dirty_vars

    def assert_array_dirty():
        assert mutable_state.dirty_vars == {"array"}
        mutable_state._clean()
        assert not mutable_state.dirty_vars

    # Test all list operations
    mutable_state.array.append(42)
    assert_array_dirty()
    mutable_state.array.extend([1, 2, 3])
    assert_array_dirty()
    mutable_state.array.insert(0, 0)
    assert_array_dirty()
    mutable_state.array.pop()
    assert_array_dirty()
    mutable_state.array.remove(42)
    assert_array_dirty()
    mutable_state.array.clear()
    assert_array_dirty()
    mutable_state.array += [1, 2, 3]
    assert_array_dirty()
    mutable_state.array.reverse()
    assert_array_dirty()
    mutable_state.array.sort()
    assert_array_dirty()
    mutable_state.array[0] = 666
    assert_array_dirty()
    del mutable_state.array[0]
    assert_array_dirty()

    # Test nested list operations
    mutable_state.array[0] = [1, 2, 3]
    assert_array_dirty()
    mutable_state.array[0].append(4)
    assert_array_dirty()
    assert isinstance(mutable_state.array[0], MutableProxy)

    # Test proxy returned from __iter__
    mutable_state.array = [{}]
    assert_array_dirty()
    assert isinstance(mutable_state.array[0], MutableProxy)
    for item in mutable_state.array:
        assert isinstance(item, MutableProxy)
        item["foo"] = "bar"
        assert_array_dirty()


def test_mutable_dict(mutable_state):
    """Test that mutable dicts are tracked correctly.

    Args:
        mutable_state: A test state.
    """
    assert not mutable_state.dirty_vars

    def assert_hashmap_dirty():
        assert mutable_state.dirty_vars == {"hashmap"}
        mutable_state._clean()
        assert not mutable_state.dirty_vars

    # Test all dict operations
    mutable_state.hashmap.update({"new_key": 43})
    assert_hashmap_dirty()
    assert mutable_state.hashmap.setdefault("another_key", 66) == "another_value"
    assert_hashmap_dirty()
    assert mutable_state.hashmap.setdefault("setdefault_key", 67) == 67
    assert_hashmap_dirty()
    assert mutable_state.hashmap.setdefault("setdefault_key", 68) == 67
    assert_hashmap_dirty()
    assert mutable_state.hashmap.pop("new_key") == 43
    assert_hashmap_dirty()
    mutable_state.hashmap.popitem()
    assert_hashmap_dirty()
    mutable_state.hashmap.clear()
    assert_hashmap_dirty()
    mutable_state.hashmap["new_key"] = 42
    assert_hashmap_dirty()
    del mutable_state.hashmap["new_key"]
    assert_hashmap_dirty()
    if sys.version_info >= (3, 9):
        mutable_state.hashmap |= {"new_key": 44}
        assert_hashmap_dirty()

    # Test nested dict operations
    mutable_state.hashmap["array"] = []
    assert_hashmap_dirty()
    mutable_state.hashmap["array"].append(1)
    assert_hashmap_dirty()
    mutable_state.hashmap["dict"] = {}
    assert_hashmap_dirty()
    mutable_state.hashmap["dict"]["key"] = 42
    assert_hashmap_dirty()
    mutable_state.hashmap["dict"]["dict"] = {}
    assert_hashmap_dirty()
    mutable_state.hashmap["dict"]["dict"]["key"] = 43
    assert_hashmap_dirty()

    # Test proxy returned from `setdefault` and `get`
    mutable_value = mutable_state.hashmap.setdefault("setdefault_mutable_key", [])
    assert_hashmap_dirty()
    assert mutable_value == []
    assert isinstance(mutable_value, MutableProxy)
    mutable_value.append("foo")
    assert_hashmap_dirty()
    mutable_value_other_ref = mutable_state.hashmap.get("setdefault_mutable_key")
    assert isinstance(mutable_value_other_ref, MutableProxy)
    assert mutable_value is not mutable_value_other_ref
    assert mutable_value == mutable_value_other_ref
    assert not mutable_state.dirty_vars
    mutable_value_other_ref.append("bar")
    assert_hashmap_dirty()

    # `pop` should NOT return a proxy, because the returned value is no longer in the dict
    mutable_value_third_ref = mutable_state.hashmap.pop("setdefault_mutable_key")
    assert not isinstance(mutable_value_third_ref, MutableProxy)
    assert_hashmap_dirty()
    mutable_value_third_ref.append("baz")
    assert not mutable_state.dirty_vars
    # Unfortunately previous refs still will mark the state dirty... nothing doing about that
    assert mutable_value.pop()
    assert_hashmap_dirty()


def test_mutable_set(mutable_state):
    """Test that mutable sets are tracked correctly.

    Args:
        mutable_state: A test state.
    """
    assert not mutable_state.dirty_vars

    def assert_set_dirty():
        assert mutable_state.dirty_vars == {"test_set"}
        mutable_state._clean()
        assert not mutable_state.dirty_vars

    # Test all set operations
    mutable_state.test_set.add(42)
    assert_set_dirty()
    mutable_state.test_set.update([1, 2, 3])
    assert_set_dirty()
    mutable_state.test_set.remove(42)
    assert_set_dirty()
    mutable_state.test_set.discard(3)
    assert_set_dirty()
    mutable_state.test_set.pop()
    assert_set_dirty()
    mutable_state.test_set.intersection_update([1, 2, 3])
    assert_set_dirty()
    mutable_state.test_set.difference_update([99])
    assert_set_dirty()
    mutable_state.test_set.symmetric_difference_update([102, 99])
    assert_set_dirty()
    mutable_state.test_set |= {1, 2, 3}
    assert_set_dirty()
    mutable_state.test_set &= {2, 3, 4}
    assert_set_dirty()
    mutable_state.test_set -= {2}
    assert_set_dirty()
    mutable_state.test_set ^= {42}
    assert_set_dirty()
    mutable_state.test_set.clear()
    assert_set_dirty()


def test_mutable_custom(mutable_state):
    """Test that mutable custom types derived from Base are tracked correctly.

    Args:
        mutable_state: A test state.
    """
    assert not mutable_state.dirty_vars

    def assert_custom_dirty():
        assert mutable_state.dirty_vars == {"custom"}
        mutable_state._clean()
        assert not mutable_state.dirty_vars

    mutable_state.custom.foo = "bar"
    assert_custom_dirty()
    mutable_state.custom.array.append(42)
    assert_custom_dirty()
    mutable_state.custom.hashmap["key"] = 68
    assert_custom_dirty()
    mutable_state.custom.test_set.add(42)
    assert_custom_dirty()
    mutable_state.custom.custom.bar = "baz"
    assert_custom_dirty()


def test_mutable_backend(mutable_state):
    """Test that mutable backend vars are tracked correctly.

    Args:
        mutable_state: A test state.
    """
    assert not mutable_state.dirty_vars

    def assert_custom_dirty():
        assert mutable_state.dirty_vars == {"_be_custom"}
        mutable_state._clean()
        assert not mutable_state.dirty_vars

    mutable_state._be_custom.foo = "bar"
    assert_custom_dirty()
    mutable_state._be_custom.array.append(42)
    assert_custom_dirty()
    mutable_state._be_custom.hashmap["key"] = 68
    assert_custom_dirty()
    mutable_state._be_custom.test_set.add(42)
    assert_custom_dirty()
    mutable_state._be_custom.custom.bar = "baz"
    assert_custom_dirty()


@pytest.mark.parametrize(
    ("copy_func",),
    [
        (copy.copy,),
        (copy.deepcopy,),
    ],
)
def test_mutable_copy(mutable_state, copy_func):
    """Test that mutable types are copied correctly.

    Args:
        mutable_state: A test state.
        copy_func: A copy function.
    """
    ms_copy = copy_func(mutable_state)
    assert ms_copy is not mutable_state
    for attr in ("array", "hashmap", "test_set", "custom"):
        assert getattr(ms_copy, attr) == getattr(mutable_state, attr)
        assert getattr(ms_copy, attr) is not getattr(mutable_state, attr)
    ms_copy.custom.array.append(42)
    assert "custom" in ms_copy.dirty_vars
    if copy_func is copy.copy:
        assert "custom" in mutable_state.dirty_vars
    else:
        assert not mutable_state.dirty_vars


@pytest.mark.parametrize(
    ("copy_func",),
    [
        (copy.copy,),
        (copy.deepcopy,),
    ],
)
def test_mutable_copy_vars(mutable_state, copy_func):
    """Test that mutable types are copied correctly.

    Args:
        mutable_state: A test state.
        copy_func: A copy function.
    """
    for attr in ("array", "hashmap", "test_set", "custom"):
        var_orig = getattr(mutable_state, attr)
        var_copy = copy_func(var_orig)
        assert var_orig is not var_copy
        assert var_orig == var_copy
        # copied vars should never be proxies, as they by definition are no longer attached to the state.
        assert not isinstance(var_copy, MutableProxy)


def test_duplicate_substate_class(duplicate_substate):
    with pytest.raises(ValueError):
        duplicate_substate()