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Fixed generate_class_instance return type hint #23

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Merged
joshvote merged 4 commits into from
May 7, 2026
Merged

Fixed generate_class_instance return type hint #23

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5898eb7
Fixed generate_class_instance type hint
joshvote May 7, 2026
7669983
Merge branch 'main' of github.com:bsgip/assertical into fixgeneratecl…
joshvote May 7, 2026
1346db9
Removed superfluous args
joshvote May 7, 2026
290dc32
Linting
joshvote May 7, 2026
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127 changes: 82 additions & 45 deletions src/assertical/fake/generator.py
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Original file line number Diff line number Diff line change
Expand Up @@ -59,7 +59,10 @@ class CollectionType(IntEnum):


SUPPORTED_COLLECTION_TYPES = {list, dict, set}
TWO_PARAMETER_COLLECTION_TYPES: set[CollectionType] = {CollectionType.OPTIONAL_DICT, CollectionType.REQUIRED_DICT}
TWO_PARAMETER_COLLECTION_TYPES: set[CollectionType] = {
CollectionType.OPTIONAL_DICT,
CollectionType.REQUIRED_DICT,
}


@dataclass
Expand Down Expand Up @@ -309,7 +312,9 @@ def is_member_public(member_name: str) -> bool:
return len(member_name) > 0 and member_name[0] != "_"


def enumerate_class_properties(t: type) -> Generator[PropertyGenerationDetails, None, None]: # noqa: C901
def enumerate_class_properties( # noqa: C901
t: type,
) -> Generator[PropertyGenerationDetails, None, None]:
"""Iterates through type t's properties returning the PropertyGenerationDetails for each discovered property.

Only "public" properties that don't exist on the BaseType will be returned
Expand All @@ -326,7 +331,6 @@ def enumerate_class_properties(t: type) -> Generator[PropertyGenerationDetails,
type_hints = TYPE_HINT_FETCHER[t_generatable_base](t)

for member_name in CLASS_MEMBER_FETCHERS[t_generatable_base](t):

# Skip members that are private OR that are public members of the base class
if not is_member_public(member_name):
continue
Expand Down Expand Up @@ -370,7 +374,10 @@ def enumerate_class_properties(t: type) -> Generator[PropertyGenerationDetails,
second_member_type = get_args(optional_arg_type)[1] if is_optional else get_args(member_type)[1]
second_optional_arg_type = get_optional_type_argument(second_member_type)
second_is_optional = second_optional_arg_type is not None
if collection_type in (CollectionType.OPTIONAL_DICT, CollectionType.REQUIRED_DICT):
if collection_type in (
CollectionType.OPTIONAL_DICT,
CollectionType.REQUIRED_DICT,
):
if is_generatable_type(second_member_type):
second_type_to_generate = get_first_generatable_primitive(
second_member_type, include_optional=False
Expand Down Expand Up @@ -425,41 +432,25 @@ def enumerate_class_properties(t: type) -> Generator[PropertyGenerationDetails,
)


def generate_class_instance( # noqa: C901
def _generate_class_instance_with_seed( # noqa: C901
t: type[AnyType],
seed: int = 1,
optional_is_none: bool = False,
generate_relationships: bool = False,
_return_seed: bool = False,
_visited_type_stack: Optional[list[type]] = None,
seed: int,
optional_is_none: bool,
generate_relationships: bool,
visited_type_stack: Optional[list[type]],
**kwargs: Any,
) -> Union[AnyType, tuple[AnyType, int]]:
"""Given a child class of a key to CLASS_INSTANCE_GENERATORS - generate an instance of that class
with all properties being assigned unique values based off of seed. The values will match type hints

Any "private" members beginning with '_' will be skipped

generate_relationships will recursively generate relationships generating instances as required. (SQL ALchemy
will handle assigning backreferences too)

If the type cannot be instantiated due to missing type hints / other info exceptions will be raised

Any additional specified "kwargs" will override the generated members. Eg generate_class_instance(Foo, my_arg="123")
will generate a new instance of Foo as per normal but the named member "my_arg" will have value "123". Please note
that this will change the way remaining values are allocated such that:
generate_class_instance(Foo, my_arg="123") != (generate_class_instance(Foo).my_arg = "123")
Specifying an invalid member name will raise an Exception

_visited_type_stack should not be specified - it's for internal use only"""
) -> tuple[AnyType, int]:
"""Internal function - performs the work of generate_class_instance but returns each generated type with an updated
seed value"""
t = remove_passthrough_type(t)

# stop back references from infinite looping
if _visited_type_stack is None:
_visited_type_stack = []
if t in _visited_type_stack:
if visited_type_stack is None:
visited_type_stack = []
if t in visited_type_stack:
# This only happens in recursion - the top level object will never be None
return (None, seed) if _return_seed else None # type: ignore
_visited_type_stack.append(t)
return (None, seed) # type: ignore
visited_type_stack.append(t)

# We can only generate class instances of classes that inherit from a known base
t_generatable_base = get_generatable_class_base(t)
Expand All @@ -473,7 +464,6 @@ def generate_class_instance( # noqa: C901
kwargs_references: set[str] = set() # For making sure we use all kwargs values to catch typos

for member in enumerate_class_properties(t):

# If there is a custom override for a member - apply it before going any further
if member.name in kwargs:
values[member.name] = kwargs[member.name]
Expand All @@ -487,34 +477,42 @@ def generate_class_instance( # noqa: C901
f"Type {t} has property {member.name} with type {member.declared_type} that cannot be generated"
)

if member.collection_type in (CollectionType.REQUIRED_DICT, CollectionType.OPTIONAL_DICT):
if member.collection_type in (
CollectionType.REQUIRED_DICT,
CollectionType.OPTIONAL_DICT,
):
if member.second_type_to_generate is None and not (
optional_is_none and member.collection_type == CollectionType.OPTIONAL_DICT
):
raise Exception(
f"Type {t} has property {member.name} with type {member.declared_type} that cannot be generated"
)

generated_value: Any = None
empty_collection: bool = False
collection_type: Optional[CollectionType] = member.collection_type

def generate_member(
is_primitive_type: bool, type_to_generate: type, current_seed: int, empty_collection: bool
is_primitive_type: bool,
type_to_generate: type,
current_seed: int,
empty_collection: bool,
) -> tuple[Any, int, bool]:
if is_primitive_type:
generated_value = generate_value(type_to_generate, seed=current_seed, optional_is_none=optional_is_none)
generated_value = generate_value(
type_to_generate,
seed=current_seed,
optional_is_none=optional_is_none,
)
current_seed += 1
else:
generated_value = None
if generate_relationships:
generated_value, current_seed = generate_class_instance(
generated_value, current_seed = _generate_class_instance_with_seed(
type_to_generate,
seed=current_seed,
optional_is_none=optional_is_none,
generate_relationships=generate_relationships,
_visited_type_stack=_visited_type_stack,
_return_seed=True,
visited_type_stack=visited_type_stack,
)

# None can be generated when Type A has child B that includes a backreference to A. in these
Expand All @@ -528,7 +526,11 @@ def generate_member(

if optional_is_none and (
member.collection_type
in [CollectionType.OPTIONAL_LIST, CollectionType.OPTIONAL_SET, CollectionType.OPTIONAL_DICT]
in [
CollectionType.OPTIONAL_LIST,
CollectionType.OPTIONAL_SET,
CollectionType.OPTIONAL_DICT,
]
):
# We can short circuit some generation if we know the top level collection should be None
# In this case - we just set everything to None
Expand Down Expand Up @@ -573,10 +575,44 @@ def generate_member(
if kwargs_references != expected_kwargs_references:
raise Exception(f"The following kwargs were unused {expected_kwargs_references.difference(kwargs_references)}")

_visited_type_stack.pop() # When we finish generating a type, allow recursion back into that type
visited_type_stack.pop() # When we finish generating a type, allow recursion back into that type

instance = CLASS_INSTANCE_GENERATORS[t_generatable_base](t, values)
return (instance, current_seed) if _return_seed else instance
return (instance, current_seed)


def generate_class_instance( # noqa: C901
t: type[AnyType],
seed: int = 1,
optional_is_none: bool = False,
generate_relationships: bool = False,
**kwargs: Any,
) -> AnyType:
"""Given a child class of a key to CLASS_INSTANCE_GENERATORS - generate an instance of that class
with all properties being assigned unique values based off of seed. The values will match type hints

Any "private" members beginning with '_' will be skipped

generate_relationships will recursively generate relationships generating instances as required. (SQL ALchemy
will handle assigning backreferences too)

If the type cannot be instantiated due to missing type hints / other info exceptions will be raised

Any additional specified "kwargs" will override the generated members. Eg generate_class_instance(Foo, my_arg="123")
will generate a new instance of Foo as per normal but the named member "my_arg" will have value "123". Please note
that this will change the way remaining values are allocated such that:
generate_class_instance(Foo, my_arg="123") != (generate_class_instance(Foo).my_arg = "123")
Specifying an invalid member name will raise an Exception"""

result, _ = _generate_class_instance_with_seed(
t,
seed=seed,
optional_is_none=optional_is_none,
generate_relationships=generate_relationships,
visited_type_stack=[],
**kwargs,
)
return result


def clone_class_instance(obj: AnyType, ignored_properties: Optional[set[str]] = None) -> AnyType:
Expand Down Expand Up @@ -696,7 +732,8 @@ def register_value_generator(t: type, generator: Callable[[int], Any]) -> None:
register_value_generator(bool, lambda seed: (seed % 2) == 0)
register_value_generator(Decimal, lambda seed: Decimal(seed))
register_value_generator(
datetime, lambda seed: datetime(2010, 1, 1, tzinfo=timezone.utc) + timedelta(days=seed) + timedelta(seconds=seed)
datetime,
lambda seed: (datetime(2010, 1, 1, tzinfo=timezone.utc) + timedelta(days=seed) + timedelta(seconds=seed)),
)
register_value_generator(time, lambda seed: time(seed % 24, seed % 60, (seed + 1) % 60))
register_value_generator(timedelta, lambda seed: timedelta(seconds=seed))
Expand Down
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