Refactor allownull integration tests

Reduce test complexity by splitting up in multiple tests, suggested
in #64 (comment)

tests/unmarshal/unmarshal_nullable_test.py

@@ -5,60 +5,66 @@
 from jsonschema.exceptions import ValidationError
 
 
-@pytest.mark.parametrize('value', ['x', None])
-@pytest.mark.parametrize('nullable', [True, False])
-def test_unmarshal_with_primitive(empty_swagger_spec, value, nullable):
-    """If the value is a primitive, validation should pass if
-    `x-nullable` is `True` and the value is `None`. `required` is not
-    possible in this scenario.
-
-    +---------------------+--------------+
-    | x-nullable == False | 'x'  -> pass |
-    |                     | None -> fail |
-    +---------------------+--------------+
-    | x-nullable == True  | 'x'  -> pass |
-    |                     | None -> pass |
-    +---------------------+--------------+
-    """
+"""If the value is a primitive, validation should pass if
+`x-nullable` is `True` and the value is `None`. `required` is not
+possible in this scenario.
+
++---------------------+------------------+
+| x-nullable == False | 'x'  -> pass (1) |
+|                     | None -> fail (2) |
++---------------------+------------------+
+| x-nullable == True  | 'x'  -> pass (3) |
+|                     | None -> pass (4) |
++---------------------+------------------+
+"""
+
+
+@pytest.mark.parametrize(['nullable', 'value'],
+                         [(False, 'x'), (True, 'x'), (True, None)])
+def test_unmarshal_with_primitive_pass(empty_swagger_spec, value, nullable):
+    """Test scenarios in which validation should pass: (1), (3), (4)"""
     content_spec = {
         'type': 'string',
         'x-nullable': nullable,
     }
+    validate_schema_object(empty_swagger_spec, content_spec, value)
+    result = unmarshal_schema_object(empty_swagger_spec, content_spec, value)
+    assert result == value
 
-    try:
+
+def test_unmarshal_with_primitive_fail(empty_swagger_spec):
+    """Test scenarios in which validation should fail: (2)"""
+    content_spec = {
+        'type': 'string',
+        'x-nullable': False,
+    }
+    value = None
+    with pytest.raises(ValidationError) as excinfo:
         validate_schema_object(empty_swagger_spec, content_spec, value)
-        result = unmarshal_schema_object(
-            empty_swagger_spec, content_spec, value)
-    except ValidationError as e:
-        result = e
+        unmarshal_schema_object(empty_swagger_spec, content_spec, value)
+    assert excinfo.value.message == "None is not of type 'string'"
 
-    if nullable is False and not value:
-        assert result.message == "None is not of type 'string'"
-    else:
-        assert result == value
 
+"""If the value is an object, validation should pass if
+`x-nullable` is `True` and the value is `None`. `required` doesn't
+have an influence.
 
-@pytest.mark.parametrize('value', [{'x': 'y'}, {'x': None}, {}])
-@pytest.mark.parametrize('nullable', [True, False])
-@pytest.mark.parametrize('required', [True, False])
-def test_unmarshal_with_object(empty_swagger_spec, value, nullable, required):
-    """If the value is an object, validation should pass if
-    `x-nullable` is `True` and the value is `None`. `required` doesn't
-    have an influence.
-
-    +---------------------+---------------------+---------------------+
-    |                     | required == False   | required == True    |
-    +---------------------+---------------------+---------------------+
-    | x-nullable == False | {}          -> pass | {}          -> fail |
-    |                     | {'x': 'y'}  -> pass | {'x': 'y'}  -> pass |
-    |                     | {'x': None} -> fail | {'x': None} -> fail |
-    +---------------------+---------------------+---------------------+
-    | x-nullable == True  | {}          -> pass | {}          -> fail |
-    |                     | {'x': 'y'}  -> pass | {'x': 'y'}  -> pass |
-    |                     | {'x': None} -> pass | {'x': None} -> pass |
-    +---------------------+---------------------+---------------------+
-    """
-    content_spec = {
++---------------------+-------------------------+--------------------------+
+|                     | required == False       | required == True         |
++---------------------+-------------------------+--------------------------+
+| x-nullable == False | {}          -> pass (1) | {}          -> fail  (4) |
+|                     | {'x': 'y'}  -> pass (2) | {'x': 'y'}  -> pass  (5) |
+|                     | {'x': None} -> fail (3) | {'x': None} -> fail  (6) |
++---------------------+-------------------------+--------------------------+
+| x-nullable == True  | {}          -> pass (7) | {}          -> fail (10) |
+|                     | {'x': 'y'}  -> pass (8) | {'x': 'y'}  -> pass (11) |
+|                     | {'x': None} -> pass (9) | {'x': None} -> pass (12) |
++---------------------+-------------------------+--------------------------+
+"""
+
+
+def content_spec_factory(required, nullable):
+    return {
         'type': 'object',
         'required': ['x'] if required else [],
         'properties': {
@@ -69,19 +75,68 @@ def test_unmarshal_with_object(empty_swagger_spec, value, nullable, required):
         }
     }
 
-    try:
+
+@pytest.mark.parametrize('nullable', [True, False])
+@pytest.mark.parametrize('required', [True, False])
+def test_unmarshal_with_object_default(empty_swagger_spec, nullable, required):
+    """With a value set, validation should always pass: (2), (5), (8), (11)"""
+    content_spec = content_spec_factory(required, nullable)
+    value = {'x': 'y'}
+
+    validate_schema_object(empty_swagger_spec, content_spec, value)
+    result = unmarshal_schema_object(empty_swagger_spec, content_spec, value)
+    assert result == value
+
+
+@pytest.mark.parametrize('nullable', [True, False])
+def test_unmarshal_with_object_req_no_value(empty_swagger_spec, nullable):
+    """When the value is required but not set at all, validation
+    should fail: (4), (10)
+    """
+    content_spec = content_spec_factory(True, nullable)
+    value = {}
+
+    with pytest.raises(ValidationError) as excinfo:
+        validate_schema_object(empty_swagger_spec, content_spec, value)
+        unmarshal_schema_object(empty_swagger_spec, content_spec, value)
+    assert excinfo.value.message == "'x' is a required property"
+
+
+@pytest.mark.parametrize('nullable', [True, False])
+def test_unmarshal_with_object_no_req_no_value(empty_swagger_spec, nullable):
+    """When the value is not required and not set at all, validation
+    should pass: (1), (7)
+    """
+    content_spec = content_spec_factory(False, nullable=nullable)
+    value = {}
+
+    validate_schema_object(empty_swagger_spec, content_spec, value)
+    result = unmarshal_schema_object(empty_swagger_spec, content_spec, value)
+    assert result == {'x': None}  # Missing parameters are re-introduced
+
+
+@pytest.mark.parametrize('required', [True, False])
+def test_unmarshal_with_object_no_null_value_none(empty_swagger_spec, required):
+    """When nullable is `False` and the value is set to `None`, validation
+    should fail: (3), (6)
+    """
+    content_spec = content_spec_factory(required, False)
+    value = {'x': None}
+
+    with pytest.raises(ValidationError) as excinfo:
         validate_schema_object(empty_swagger_spec, content_spec, value)
-        result = unmarshal_schema_object(
-            empty_swagger_spec, content_spec, value)
-    except ValidationError as e:
-        result = e
-
-    if value == {} and required is True:
-        assert result.message == "'x' is a required property"
-    elif value == {} and required is False:
-        # Unmarshal re-introduces missing properties with None which is ok.
-        assert result == {'x': None}
-    elif nullable is False and value['x'] is None:
-        assert result.message == "None is not of type 'string'"
-    else:
-        result == value
+        unmarshal_schema_object(empty_swagger_spec, content_spec, value)
+    assert excinfo.value.message == "None is not of type 'string'"
+
+
+@pytest.mark.parametrize('required', [True, False])
+def test_unmarshal_with_object_null_value_none(empty_swagger_spec, required):
+    """When nullable is `True` and the value is set to `None`, validation
+    should pass: (9), (12)
+    """
+    content_spec = content_spec_factory(required, True)
+    value = {'x': None}
+
+    validate_schema_object(empty_swagger_spec, content_spec, value)
+    result = unmarshal_schema_object(empty_swagger_spec, content_spec, value)
+    assert result == {'x': None}