Strict validation of list, set and tuple (#86) (#200)

* Strict validation of `list`, `set` and `tuple` (#86)

* review fixes

HISTORY.rst

@@ -3,6 +3,10 @@
 History
 -------
 
+v0.10.1 (2018-xx-xx)
+....................
+* make ``list``, ``tuple`` and ``set`` types stricter #86
+
 v0.10.0 (2018-06-11)
 ....................
 * add ``Config.allow_population_by_alias`` #160, thanks @bendemaree

pydantic/validators.py

@@ -1,3 +1,4 @@
+import inspect
 from collections import OrderedDict
 from datetime import date, datetime, time, timedelta
 from decimal import Decimal, DecimalException
@@ -133,25 +134,28 @@ def dict_validator(v) -> dict:
 def list_validator(v) -> list:
     if isinstance(v, list):
         return v
-
-    with change_exception(errors.ListError, TypeError):
+    elif isinstance(v, (tuple, set)) or inspect.isgenerator(v):
         return list(v)
+    else:
+        raise errors.ListError()
 
 
 def tuple_validator(v) -> tuple:
     if isinstance(v, tuple):
         return v
-
-    with change_exception(errors.TupleError, TypeError):
+    elif isinstance(v, (list, set)) or inspect.isgenerator(v):
         return tuple(v)
+    else:
+        raise errors.TupleError()
 
 
 def set_validator(v) -> set:
     if isinstance(v, set):
         return v
-
-    with change_exception(errors.SetError, TypeError):
+    elif isinstance(v, (list, tuple)) or inspect.isgenerator(v):
         return set(v)
+    else:
+        raise errors.SetError()
 
 
 def enum_validator(v, field, config, **kwargs) -> Enum:

tests/test_types.py

@@ -428,16 +428,29 @@ def test_dict():
     ]
 
 
-def test_list():
+@pytest.mark.parametrize('value,result', (
+    ([1, 2, '3'], [1, 2, '3']),
+    ((1, 2, '3'), [1, 2, '3']),
+    ({1, 2, '3'}, [1, 2, '3']),
+    ((i**2 for i in range(5)), [0, 1, 4, 9, 16]),
+))
+def test_list_success(value, result):
     class Model(BaseModel):
         v: list
 
-    assert Model(v=[1, 2, '3']).v == [1, 2, '3']
-    assert Model(v='xyz').v == ['x', 'y', 'z']
-    assert Model(v=(i**2 for i in range(5))).v == [0, 1, 4, 9, 16]
+    assert Model(v=value).v == result
+
+
+@pytest.mark.parametrize('value', (
+    123,
+    '123',
+))
+def test_list_fails(value):
+    class Model(BaseModel):
+        v: list
 
     with pytest.raises(ValidationError) as exc_info:
-        Model(v=1)
+        Model(v=value)
     assert exc_info.value.errors() == [
         {
             'loc': ('v',),
@@ -466,16 +479,29 @@ def test_ordered_dict():
     ]
 
 
-def test_tuple():
+@pytest.mark.parametrize('value,result', (
+    ([1, 2, '3'], (1, 2, '3')),
+    ((1, 2, '3'), (1, 2, '3')),
+    ({1, 2, '3'}, (1, 2, '3')),
+    ((i**2 for i in range(5)), (0, 1, 4, 9, 16)),
+))
+def test_tuple_success(value, result):
     class Model(BaseModel):
         v: tuple
 
-    assert Model(v=(1, 2, '3')).v == (1, 2, '3')
-    assert Model(v='xyz').v == ('x', 'y', 'z')
-    assert Model(v=(i**2 for i in range(5))).v == (0, 1, 4, 9, 16)
+    assert Model(v=value).v == result
+
+
+@pytest.mark.parametrize('value', (
+    123,
+    '123',
+))
+def test_tuple_fails(value):
+    class Model(BaseModel):
+        v: tuple
 
     with pytest.raises(ValidationError) as exc_info:
-        Model(v=1)
+        Model(v=value)
     assert exc_info.value.errors() == [
         {
             'loc': ('v',),
@@ -485,16 +511,29 @@ def test_tuple():
     ]
 
 
-def test_set():
+@pytest.mark.parametrize('value,result', (
+    ({1, 2, 2, '3'}, {1, 2, '3'}),
+    ((1, 2, 2, '3'), {1, 2, '3'}),
+    ([1, 2, 2, '3'], {1, 2, '3'}),
+    ({i**2 for i in range(5)}, {0, 1, 4, 9, 16}),
+))
+def test_set_success(value, result):
     class Model(BaseModel):
         v: set
 
-    assert Model(v={1, 2, 2, '3'}).v == {1, 2, '3'}
-    assert Model(v='xyzxyz').v == {'x', 'y', 'z'}
-    assert Model(v={i**2 for i in range(5)}).v == {0, 1, 4, 9, 16}
+    assert Model(v=value).v == result
+
+
+@pytest.mark.parametrize('value', (
+    123,
+    '123',
+))
+def test_set_fails(value):
+    class Model(BaseModel):
+        v: set
 
     with pytest.raises(ValidationError) as exc_info:
-        Model(v=1)
+        Model(v=value)
     assert exc_info.value.errors() == [
         {
             'loc': ('v',),