Work on dicts

Author: Tinche

src/cattrs/v/__init__.py

@@ -1,5 +1,5 @@
 """Cattrs validation."""
-from typing import Any, Callable, List, Tuple, Type, TypeVar, Union, overload
+from typing import Any, Callable, Dict, List, Tuple, Type, TypeVar, Union, overload
 
 from attrs import NOTHING, frozen
 
@@ -152,6 +152,7 @@ def transform_error(
 
 T = TypeVar("T")
 E = TypeVar("E")
+TV = TypeVar("TV")
 
 
 @overload
@@ -161,15 +162,30 @@ def ensure(
     ...
 
 
+@overload
+def ensure(
+    type: Type[Dict],
+    *validators: Callable[[Dict], Any],
+    keys: Type[E],
+    values: Type[TV],
+) -> Type[Dict[E, TV]]:
+    ...
+
+
 @overload
 def ensure(type: Type[T], *validators: Callable[[T], Any]) -> Type[T]:
     ...
 
 
-def ensure(type: Any, *validators: Any, elems: Any = NOTHING) -> Any:
+def ensure(type, *validators, elems=NOTHING, keys=NOTHING, values=NOTHING):
+    """Ensure validators run when structuring the given type."""
     if elems is not NOTHING:
         # These are lists.
         if not validators:
             return type[elems]
-        return Annotated[type, VAnnotation(*validators)]
+        return Annotated[type[elems], VAnnotation(*validators)]
+    if keys is not NOTHING or values is not NOTHING:
+        if not validators:
+            return type[keys, values]
+        return Annotated[type[keys, values], VAnnotation(*validators)]
     return Annotated[type, VAnnotation(*validators)]

tests/v/test_ensure.py

@@ -1,18 +1,19 @@
 """Tests for `cattrs.v.ensure`."""
 import sys
-from typing import List, MutableSequence, Sequence
+from typing import Dict, List, MutableSequence, Sequence
 
 from pytest import fixture, mark, raises
 
 from cattrs import BaseConverter
 from cattrs._compat import ExceptionGroup
+from cattrs.errors import IterableValidationError
 from cattrs.v import ensure
 from cattrs.v._hooks import is_validated, validator_factory
 
 
 @fixture
 def valconv(converter) -> BaseConverter:
-    converter.register_structure_hook_factory(is_validated)(validator_factory)
+    converter.register_structure_hook_factory(is_validated, validator_factory)
     return converter
 
 
@@ -38,7 +39,7 @@ def test_ensured_lists(valconv: BaseConverter):
         valconv.structure([], ensure(List[int], lambda lst: len(lst) > 0))
 
     if valconv.detailed_validation:
-        assert isinstance(exc.value, ExceptionGroup)
+        assert isinstance(exc.value, IterableValidationError)
         assert isinstance(exc.value.exceptions[0], ValueError)
     else:
         assert isinstance(exc.value, ValueError)
@@ -53,7 +54,53 @@ def test_ensured_list_elements(valconv: BaseConverter, type):
         valconv.structure([1, -2], ensure(type, elems=ensure(int, lambda i: i > 0)))
 
     if valconv.detailed_validation:
-        assert isinstance(exc.value, ExceptionGroup)
+        assert isinstance(exc.value, IterableValidationError)
+        assert isinstance(exc.value.exceptions[0], ExceptionGroup)
+        assert isinstance(exc.value.exceptions[0].exceptions[0], ValueError)
+    else:
+        assert isinstance(exc.value, ValueError)
+
+    # Now both elements and the list itself.
+    assert valconv.structure(
+        [1, 2],
+        ensure(type, lambda lst: len(lst) < 3, elems=ensure(int, lambda i: i > 0)),
+    )
+
+    with raises(Exception) as exc:
+        valconv.structure(
+            [1, 2, 3],
+            ensure(type, lambda lst: len(lst) < 3, elems=ensure(int, lambda i: i > 0)),
+        )
+
+    if valconv.detailed_validation:
+        assert isinstance(exc.value, IterableValidationError)
+        assert isinstance(exc.value.exceptions[0], ValueError)
+    else:
+        assert isinstance(exc.value, ValueError)
+
+    with raises(Exception) as exc:
+        valconv.structure(
+            [1, -2],
+            ensure(type, lambda lst: len(lst) < 3, elems=ensure(int, lambda i: i > 0)),
+        )
+
+    if valconv.detailed_validation:
+        assert isinstance(exc.value, IterableValidationError)
+        assert isinstance(exc.value.exceptions[0], ExceptionGroup)
+        assert isinstance(exc.value.exceptions[0].exceptions[0], ValueError)
+    else:
+        assert isinstance(exc.value, ValueError)
+
+
+def test_ensured_typing_list(valconv: BaseConverter):
+    """Ensure works for typing lists."""
+    assert valconv.structure([1, 2], ensure(List, elems=ensure(int, lambda i: i > 0)))
+
+    with raises(Exception) as exc:
+        valconv.structure([1, -2], ensure(List, elems=ensure(int, lambda i: i > 0)))
+
+    if valconv.detailed_validation:
+        assert isinstance(exc.value, IterableValidationError)
         assert isinstance(exc.value.exceptions[0], ExceptionGroup)
         assert isinstance(exc.value.exceptions[0].exceptions[0], ValueError)
     else:
@@ -63,13 +110,42 @@ def test_ensured_list_elements(valconv: BaseConverter, type):
 @mark.skipif(sys.version_info[:2] < (3, 10), reason="Not supported on older Pythons")
 def test_ensured_list(valconv: BaseConverter):
     """Ensure works for builtin lists."""
-    assert valconv.structure([1, 2], ensure(List, elems=ensure(int, lambda i: i > 0)))
+    assert valconv.structure([1, 2], ensure(list, elems=ensure(int, lambda i: i > 0)))
 
     with raises(Exception) as exc:
-        valconv.structure([1, -2], ensure(List, elems=ensure(int, lambda i: i > 0)))
+        valconv.structure([1, -2], ensure(list, elems=ensure(int, lambda i: i > 0)))
 
     if valconv.detailed_validation:
-        assert isinstance(exc.value, ExceptionGroup)
+        assert isinstance(exc.value, IterableValidationError)
+        assert isinstance(exc.value.exceptions[0], ExceptionGroup)
+        assert isinstance(exc.value.exceptions[0].exceptions[0], ValueError)
+    else:
+        assert isinstance(exc.value, ValueError)
+
+
+def test_ensured_typing_dict(valconv: BaseConverter):
+    """Ensure works for typing.Dicts."""
+    assert valconv.structure(
+        {"a": 1}, ensure(Dict, lambda d: len(d) > 0, keys=str, values=int)
+    )
+
+    with raises(Exception) as exc:
+        valconv.structure({}, ensure(Dict, lambda d: len(d) > 0, keys=str, values=int))
+
+    if valconv.detailed_validation:
+        assert isinstance(exc.value, IterableValidationError)
+        assert isinstance(exc.value.exceptions[0], ValueError)
+    else:
+        assert isinstance(exc.value, ValueError)
+
+    with raises(Exception) as exc:
+        valconv.structure(
+            {"b": 1, "c": "a"},
+            ensure(Dict, keys=ensure(str, lambda s: s.startswith("a")), values=int),
+        )
+
+    if valconv.detailed_validation:
+        assert isinstance(exc.value, IterableValidationError)
         assert isinstance(exc.value.exceptions[0], ExceptionGroup)
         assert isinstance(exc.value.exceptions[0].exceptions[0], ValueError)
     else: