# imports
from typing import Any, Callable

import pytest  # used for our unit tests


# Mock class to use for testing
class MockClass:
    pass

# Mock object with __set_name__ method
class MockWithSetName:
    def __set_name__(self, cls, name):
        self.cls = cls
        self.name = name

# Mock object with non-callable __set_name__ attribute
class MockWithNonCallableSetName:
    __set_name__ = None

# Mock object with overridden __set_name__ method
class MockWithOverriddenSetName:
    def __set_name__(self, cls, name):
        raise Exception("Unexpected")

# Placeholder for PydanticUndefined
PydanticUndefined = object()
from pydantic.fields import ModelPrivateAttr

# unit tests

def test_set_name_with_pydantic_undefined():
    """Test __set_name__ with default as PydanticUndefined."""
    attr = ModelPrivateAttr()
    attr.__set_name__(MockClass, 'attr_name')
    # No exception should be raised and no action should be taken

def test_set_name_with_default_lacking_set_name():
    """Test __set_name__ with default lacking __set_name__ method."""
    attr = ModelPrivateAttr(default=42)
    attr.__set_name__(MockClass, 'attr_name')
    # No exception should be raised and no action should be taken

def test_set_name_with_default_having_non_callable_set_name():
    """Test __set_name__ with default having non-callable __set_name__ attribute."""
    attr = ModelPrivateAttr(default=MockWithNonCallableSetName())
    attr.__set_name__(MockClass, 'attr_name')
    # No exception should be raised and no action should be taken

def test_set_name_with_default_having_callable_set_name():
    """Test __set_name__ with default having callable __set_name__ method."""
    mock = MockWithSetName()
    attr = ModelPrivateAttr(default=mock)
    attr.__set_name__(MockClass, 'attr_name')
    assert mock.cls == MockClass
    assert mock.name == 'attr_name'

def test_set_name_with_default_having_overridden_set_name():
    """Test __set_name__ with default having overridden __set_name__ method."""
    mock = MockWithOverriddenSetName()
    attr = ModelPrivateAttr(default=mock)
    with pytest.raises(Exception, match="Unexpected"):
        attr.__set_name__(MockClass, 'attr_name')

def test_set_name_with_default_as_descriptor():
    """Test __set_name__ with default as a descriptor."""
    class SomeDescriptor:
        def __get__(self, instance, owner):
            pass
    attr = ModelPrivateAttr(default=SomeDescriptor())
    attr.__set_name__(MockClass, 'attr_name')
    # No exception should be raised and no action should be taken

def test_set_name_with_default_factory_raising_exception():
    """Test __set_name__ with default factory raising an exception."""
    attr = ModelPrivateAttr(default_factory=lambda: 1 / 0)
    attr.__set_name__(MockClass, 'attr_name')
    # No exception should be raised and no action should be taken

def test_set_name_with_highly_nested_default():
    """Test __set_name__ with highly nested default values."""
    attr = ModelPrivateAttr(default=[[[[[42]]]]])
    attr.__set_name__(MockClass, 'attr_name')
    # No exception should be raised and no action should be taken

def test_set_name_with_circular_reference_default():
    """Test __set_name__ with default containing circular references."""
    a = []
    a.append(a)
    attr = ModelPrivateAttr(default=a)
    attr.__set_name__(MockClass, 'attr_name')
    # No exception should be raised and no action should be taken

def test_set_name_with_default_factory_side_effects():
    """Test __set_name__ with default factory having side effects."""
    global_list = []
    attr = ModelPrivateAttr(default_factory=lambda: global_list.append(42))
    attr.__set_name__(MockClass, 'attr_name')
    assert global_list == [42]