Bump test dependencies (#673)

* Bump some test dependencies

* Tweak tests for coverage

* Small test refactor

* Rebump coverage, pin Hypothesis

* Fix tests

* Docs and test

* Bump Hypothesis, rework `FAST`

* Move tests around

* Remove unused imports

* Refactor `kw_only` to a FeatureFlag

* Remove unused import

Author: Tinche

HISTORY.md

@@ -32,6 +32,9 @@ Our backwards-compatibility policy can be found [here](https://github.com/python
 - For {class}`cattrs.errors.StructureHandlerNotFoundError` and {class}`cattrs.errors.ForbiddenExtraKeysError`
   correctly set {attr}`BaseException.args` in `super()` and hence make them pickable.
   ([#666](https://github.com/python-attrs/cattrs/pull/666))
+- The default disambiguation hook factory is now only enabled for converters with `unstructure_strat=AS_DICT` (the default).
+  Since the strategy doesn't support tuples, it is skipped for `unstructure_strat=AS_TUPLE` converters.
+  ([#673](https://github.com/python-attrs/cattrs/pull/673))
 
 ## 25.1.1 (2025-06-04)
 

pdm.lock

@@ -7,12 +7,12 @@ lint = [
     "ruff>=0.12.2",
 ]
 test = [
-    "hypothesis>=6.111.2",
-    "pytest>=8.3.2",
-    "pytest-benchmark>=4.0.0",
-    "immutables>=0.20",
-    "coverage>=7.6.1",
-    "pytest-xdist>=3.6.1",
+    "hypothesis>=6.135.26",
+    "pytest>=8.4.1",
+    "pytest-benchmark>=5.1.0",
+    "immutables>=0.21",
+    "coverage>=7.9.2",
+    "pytest-xdist>=3.8.0",
 ]
 docs = [
     "sphinx>=5.3.0",

pyproject.toml

@@ -281,7 +281,11 @@ def __init__(
                 (is_tuple, self._structure_tuple),
                 (is_namedtuple, namedtuple_structure_factory, "extended"),
                 (is_mapping, self._structure_dict),
-                (is_supported_union, self._gen_attrs_union_structure, True),
+                *(
+                    [(is_supported_union, self._gen_attrs_union_structure, True)]
+                    if unstruct_strat is UnstructureStrategy.AS_DICT
+                    else []
+                ),
                 (is_optional, self._structure_optional),
                 (
                     lambda t: is_union_type(t) and t in self._union_struct_registry,

src/cattrs/converters.py

@@ -28,7 +28,7 @@ def converter_cls(request):
 )
 settings.register_profile("fast", settings.get_profile("tests"), max_examples=10)
 
-settings.load_profile("fast" if "FAST" in environ else "tests")
+settings.load_profile("fast" if environ.get("FAST") == "1" else "tests")
 
 collect_ignore_glob = []
 if sys.version_info < (3, 10):

tests/conftest.py

@@ -8,6 +8,7 @@
 from hypothesis.strategies import just, one_of
 
 from cattrs import BaseConverter, UnstructureStrategy
+from cattrs.errors import StructureHandlerNotFoundError
 
 from ._compat import is_py310_plus
 from .typed import nested_typed_classes, simple_typed_attrs, simple_typed_classes
@@ -28,7 +29,7 @@ def test_simple_roundtrip(cls_and_vals, strat):
 
 
 @given(
-    simple_typed_attrs(defaults=True, newtypes=False, allow_nan=False),
+    simple_typed_attrs(defaults="always", newtypes=False, allow_nan=False),
     unstructure_strats,
 )
 def test_simple_roundtrip_defaults(attr_and_strat, strat):
@@ -58,7 +59,7 @@ def test_nested_roundtrip(cls_and_vals):
     assert inst == converter.structure(converter.unstructure(inst), cl)
 
 
-@given(nested_typed_classes(kw_only=False, newtypes=False, allow_nan=False))
+@given(nested_typed_classes(kw_only="never", newtypes=False, allow_nan=False))
 def test_nested_roundtrip_tuple(cls_and_vals):
     """
     Nested classes with metadata can be unstructured and restructured.
@@ -71,24 +72,24 @@ def test_nested_roundtrip_tuple(cls_and_vals):
     assert inst == converter.structure(converter.unstructure(inst), cl)
 
 
-@settings(suppress_health_check=[HealthCheck.filter_too_much, HealthCheck.too_slow])
+@settings(suppress_health_check=[HealthCheck.too_slow])
 @given(
-    simple_typed_classes(defaults=False, newtypes=False, allow_nan=False),
-    simple_typed_classes(defaults=False, newtypes=False, allow_nan=False),
-    unstructure_strats,
+    simple_typed_classes(
+        defaults="never", newtypes=False, allow_nan=False, min_attrs=2
+    ),
+    simple_typed_classes(
+        defaults="never", newtypes=False, allow_nan=False, min_attrs=1
+    ),
 )
-def test_union_field_roundtrip(cl_and_vals_a, cl_and_vals_b, strat):
+def test_union_field_roundtrip_dict(cl_and_vals_a, cl_and_vals_b):
     """
     Classes with union fields can be unstructured and structured.
     """
-    converter = BaseConverter(unstruct_strat=strat)
+    converter = BaseConverter()
     cl_a, vals_a, kwargs_a = cl_and_vals_a
-    assume(strat is UnstructureStrategy.AS_DICT or not kwargs_a)
-    cl_b, vals_b, _ = cl_and_vals_b
+    cl_b, _, _ = cl_and_vals_b
     a_field_names = {a.name for a in fields(cl_a)}
     b_field_names = {a.name for a in fields(cl_b)}
-    assume(a_field_names)
-    assume(b_field_names)
 
     common_names = a_field_names & b_field_names
     assume(len(a_field_names) > len(common_names))
@@ -99,25 +100,55 @@ class C:
 
     inst = C(a=cl_a(*vals_a, **kwargs_a))
 
-    if strat is UnstructureStrategy.AS_DICT:
-        assert inst == converter.structure(converter.unstructure(inst), C)
-    else:
-        # Our disambiguation functions only support dictionaries for now.
-        with pytest.raises(ValueError):
-            converter.structure(converter.unstructure(inst), C)
+    unstructured = converter.unstructure(inst)
+    assert inst == converter.structure(converter.unstructure(unstructured), C)
 
-        def handler(obj, _):
-            return converter.structure(obj, cl_a)
 
-        converter.register_structure_hook(Union[cl_a, cl_b], handler)
-        assert inst == converter.structure(converter.unstructure(inst), C)
+@settings(suppress_health_check=[HealthCheck.too_slow])
+@given(
+    simple_typed_classes(
+        defaults="never", newtypes=False, allow_nan=False, kw_only="never", min_attrs=2
+    ),
+    simple_typed_classes(
+        defaults="never", newtypes=False, allow_nan=False, kw_only="never", min_attrs=1
+    ),
+)
+def test_union_field_roundtrip_tuple(cl_and_vals_a, cl_and_vals_b):
+    """
+    Classes with union fields can be unstructured and structured.
+    """
+    converter = BaseConverter(unstruct_strat=UnstructureStrategy.AS_TUPLE)
+    cl_a, vals_a, _ = cl_and_vals_a
+    cl_b, _, _ = cl_and_vals_b
+
+    @define
+    class C:
+        a: Union[cl_a, cl_b]
+
+    inst = C(a=cl_a(*vals_a))
+
+    # Our disambiguation functions only support dictionaries for now.
+    raw = converter.unstructure(inst)
+    with pytest.raises(StructureHandlerNotFoundError):
+        converter.structure(raw, C)
+
+    def handler(obj, _):
+        return converter.structure(obj, cl_a)
+
+    converter.register_structure_hook(Union[cl_a, cl_b], handler)
+    unstructured = converter.unstructure(inst)
+    assert inst == converter.structure(unstructured, C)
 
 
 @pytest.mark.skipif(not is_py310_plus, reason="3.10+ union syntax")
-@settings(suppress_health_check=[HealthCheck.filter_too_much, HealthCheck.too_slow])
+@settings(suppress_health_check=[HealthCheck.too_slow])
 @given(
-    simple_typed_classes(defaults=False, newtypes=False, allow_nan=False),
-    simple_typed_classes(defaults=False, newtypes=False, allow_nan=False),
+    simple_typed_classes(
+        defaults="never", newtypes=False, allow_nan=False, min_attrs=1
+    ),
+    simple_typed_classes(
+        defaults="never", newtypes=False, allow_nan=False, min_attrs=1
+    ),
     unstructure_strats,
 )
 def test_310_union_field_roundtrip(cl_and_vals_a, cl_and_vals_b, strat):
@@ -126,12 +157,10 @@ def test_310_union_field_roundtrip(cl_and_vals_a, cl_and_vals_b, strat):
     """
     converter = BaseConverter(unstruct_strat=strat)
     cl_a, vals_a, kwargs_a = cl_and_vals_a
-    cl_b, vals_b, _ = cl_and_vals_b
+    cl_b, _, _ = cl_and_vals_b
     assume(strat is UnstructureStrategy.AS_DICT or not kwargs_a)
     a_field_names = {a.name for a in fields(cl_a)}
     b_field_names = {a.name for a in fields(cl_b)}
-    assume(a_field_names)
-    assume(b_field_names)
 
     common_names = a_field_names & b_field_names
     assume(len(a_field_names) > len(common_names))
@@ -146,7 +175,7 @@ class C:
         assert inst == converter.structure(converter.unstructure(inst), C)
     else:
         # Our disambiguation functions only support dictionaries for now.
-        with pytest.raises(ValueError):
+        with pytest.raises(StructureHandlerNotFoundError):
             converter.structure(converter.unstructure(inst), C)
 
         def handler(obj, _):
@@ -156,7 +185,7 @@ def handler(obj, _):
         assert inst == converter.structure(converter.unstructure(inst), C)
 
 
-@given(simple_typed_classes(defaults=False, newtypes=False, allow_nan=False))
+@given(simple_typed_classes(defaults="never", newtypes=False, allow_nan=False))
 def test_optional_field_roundtrip(cl_and_vals):
     """
     Classes with optional fields can be unstructured and structured.
@@ -178,7 +207,7 @@ class C:
 
 
 @pytest.mark.skipif(not is_py310_plus, reason="3.10+ union syntax")
-@given(simple_typed_classes(defaults=False, newtypes=False, allow_nan=False))
+@given(simple_typed_classes(defaults="never", newtypes=False, allow_nan=False))
 def test_310_optional_field_roundtrip(cl_and_vals):
     """
     Classes with optional fields can be unstructured and structured.