diff --git a/pyproject.toml b/pyproject.toml
index 406541c..8aafbf8 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -76,4 +76,13 @@ exclude = [
     "target",
     "*.egg-info",
     ".git",
-    ]
+]
+
+[tool.coverage.report]
+exclude_lines = [
+    "if __name__ == .__main__.:",
+    "raise NotImplemented.",
+    "return NotImplemented",
+    "def __repr__",
+    "...",
+]
diff --git a/rolo/dispatcher.py b/rolo/dispatcher.py
index a309d80..05772b0 100644
--- a/rolo/dispatcher.py
+++ b/rolo/dispatcher.py
@@ -72,9 +72,6 @@ def __call__(self, request: Request, **kwargs) -> ResultValue:
 
 
 def _try_parse_pydantic_request_body(request: Request, endpoint: Handler) -> Optional[dict]:
-    if not request.content_length:
-        return None
-
     if not inspect.isfunction(endpoint) and not inspect.ismethod(endpoint):
         # cannot yet dispatch to other callables (e.g. an object with a `__call__` method)
         return None
@@ -92,6 +89,10 @@ def _try_parse_pydantic_request_body(request: Request, endpoint: Handler) -> Opt
     if arg_type is None:
         return None
 
+    if not request.content_length:
+        # forces a Validation error "Invalid JSON: EOF while parsing a value at line 1 column 0"
+        arg_type.model_validate_json(b"")
+
     # TODO: error handling
     obj = request.get_json(force=True)
 
diff --git a/tests/test_dispatcher.py b/tests/test_dispatcher.py
index a5749ec..b9f9954 100644
--- a/tests/test_dispatcher.py
+++ b/tests/test_dispatcher.py
@@ -1,6 +1,5 @@
 from typing import Any, Dict
 
-import pydantic
 import pytest
 from werkzeug.exceptions import NotFound
 
@@ -81,65 +80,3 @@ def handler(_request: Request):
 
         router.add("/", handler)
         assert router.dispatch(Request("GET", "/")).status_code == 200
-
-
-class TestPydanticHandlerDispatcher:
-    def test_request_arg(self):
-        router = Router(dispatcher=handler_dispatcher())
-
-        class MyItem(pydantic.BaseModel):
-            name: str
-            price: float
-            is_offer: bool = None
-
-        def handler(_request: Request, item_id: int, item: MyItem) -> str:
-            return item.model_dump_json()
-
-        router.add("/items/<item_id>", handler)
-
-        request = Request("POST", "/items/123", body=b'{"name":"rolo","price":420.69}')
-        assert router.dispatch(request).data == b'{"name":"rolo","price":420.69,"is_offer":null}'
-
-    def test_response(self):
-        router = Router(dispatcher=handler_dispatcher())
-
-        class MyItem(pydantic.BaseModel):
-            name: str
-            price: float
-            is_offer: bool = None
-
-        def handler(_request: Request, item_id: int) -> MyItem:
-            return MyItem(name="rolo", price=420.69)
-
-        router.add("/items/<item_id>", handler)
-
-        request = Request("GET", "/items/123")
-        assert router.dispatch(request).get_json() == {
-            "name": "rolo",
-            "price": 420.69,
-            "is_offer": None,
-        }
-
-    def test_request_arg_validation_error(self):
-        router = Router(dispatcher=handler_dispatcher())
-
-        class MyItem(pydantic.BaseModel):
-            name: str
-            price: float
-            is_offer: bool = None
-
-        def handler(_request: Request, item_id: int, item: MyItem) -> str:
-            return item.model_dump_json()
-
-        router.add("/items/<item_id>", handler)
-
-        request = Request("POST", "/items/123", body=b'{"name":"rolo"}')
-        assert router.dispatch(request).get_json() == [
-            {
-                "type": "missing",
-                "loc": ["price"],
-                "msg": "Field required",
-                "input": {"name": "rolo"},
-                "url": "https://errors.pydantic.dev/2.8/v/missing",
-            }
-        ]
diff --git a/tests/test_pydantic.py b/tests/test_pydantic.py
new file mode 100644
index 0000000..ebed2c3
--- /dev/null
+++ b/tests/test_pydantic.py
@@ -0,0 +1,157 @@
+import pydantic
+import pytest
+
+from rolo import Request, Router, dispatcher, resource
+from rolo.dispatcher import handler_dispatcher
+
+
+class MyItem(pydantic.BaseModel):
+    name: str
+    price: float
+    is_offer: bool = None
+
+
+class TestPydanticHandlerDispatcher:
+    def test_request_arg(self):
+        router = Router(dispatcher=handler_dispatcher())
+
+        def handler(_request: Request, item: MyItem) -> dict:
+            return {"item": item.model_dump()}
+
+        router.add("/items", handler)
+
+        request = Request("POST", "/items", body=b'{"name":"rolo","price":420.69}')
+        assert router.dispatch(request).get_json(force=True) == {
+            "item": {
+                "name": "rolo",
+                "price": 420.69,
+                "is_offer": None,
+            },
+        }
+
+    def test_request_args(self):
+        router = Router(dispatcher=handler_dispatcher())
+
+        def handler(_request: Request, item_id: int, item: MyItem) -> dict:
+            return {"item_id": item_id, "item": item.model_dump()}
+
+        router.add("/items/<int:item_id>", handler)
+
+        request = Request("POST", "/items/123", body=b'{"name":"rolo","price":420.69}')
+        assert router.dispatch(request).get_json(force=True) == {
+            "item_id": "123",
+            "item": {
+                "name": "rolo",
+                "price": 420.69,
+                "is_offer": None,
+            },
+        }
+
+    def test_request_args_empty_body(self):
+        router = Router(dispatcher=handler_dispatcher())
+
+        def handler(_request: Request, item_id: int, item: MyItem) -> dict:
+            return {"item_id": item_id, "item": item.model_dump()}
+
+        router.add("/items/<int:item_id>", handler)
+
+        request = Request("POST", "/items/123", body=b"")
+        assert router.dispatch(request).get_json(force=True) == [
+            {
+                "type": "json_invalid",
+                "loc": [],
+                "msg": "Invalid JSON: EOF while parsing a value at line 1 column 0",
+                "ctx": {"error": "EOF while parsing a value at line 1 column 0"},
+                "input": "",
+                "url": "https://errors.pydantic.dev/2.8/v/json_invalid",
+            }
+        ]
+
+    def test_response(self):
+        router = Router(dispatcher=handler_dispatcher())
+
+        def handler(_request: Request, item_id: int) -> MyItem:
+            return MyItem(name="rolo", price=420.69)
+
+        router.add("/items/<int:item_id>", handler)
+
+        request = Request("GET", "/items/123")
+        assert router.dispatch(request).get_json() == {
+            "name": "rolo",
+            "price": 420.69,
+            "is_offer": None,
+        }
+
+    def test_request_arg_validation_error(self):
+        router = Router(dispatcher=handler_dispatcher())
+
+        def handler(_request: Request, item_id: int, item: MyItem) -> str:
+            return item.model_dump_json()
+
+        router.add("/items/<int:item_id>", handler)
+
+        request = Request("POST", "/items/123", body=b'{"name":"rolo"}')
+        assert router.dispatch(request).get_json() == [
+            {
+                "type": "missing",
+                "loc": ["price"],
+                "msg": "Field required",
+                "input": {"name": "rolo"},
+                "url": "https://errors.pydantic.dev/2.8/v/missing",
+            }
+        ]
+
+    def test_missing_annotation(self):
+        router = Router(dispatcher=handler_dispatcher())
+
+        # without an annotation, we cannot be sure what type to serialize into, so the dispatcher doesn't pass
+        # anything into ``item``.
+        def handler(_request: Request, item=None) -> dict:
+            return {"item": item}
+
+        router.add("/items", handler)
+
+        request = Request("POST", "/items", body=b'{"name":"rolo","price":420.69}')
+        assert router.dispatch(request).get_json(force=True) == {"item": None}
+
+    def test_with_pydantic_disabled(self, monkeypatch):
+        monkeypatch.setattr(dispatcher, "ENABLE_PYDANTIC", False)
+        router = Router(dispatcher=handler_dispatcher())
+
+        def handler(_request: Request, item: MyItem) -> dict:
+            return {"item": item.model_dump()}
+
+        router.add("/items", handler)
+
+        request = Request("POST", "/items", body=b'{"name":"rolo","price":420.69}')
+        with pytest.raises(TypeError):
+            # "missing 1 required positional argument: 'item'"
+            assert router.dispatch(request)
+
+    def test_with_resource(self):
+        router = Router(dispatcher=handler_dispatcher())
+
+        @resource("/items/<int:item_id>")
+        class MyResource:
+            def on_get(self, request: Request, item_id: int):
+                return MyItem(name="rolo", price=420.69)
+
+            def on_post(self, request: Request, item_id: int, item: MyItem):
+                return {"item_id": item_id, "item": item.model_dump()}
+
+        router.add(MyResource())
+
+        response = router.dispatch(Request("GET", "/items/123"))
+        assert response.get_json() == {
+            "name": "rolo",
+            "price": 420.69,
+            "is_offer": None,
+        }
+
+        response = router.dispatch(
+            Request("POST", "/items/123", body=b'{"name":"rolo","price":420.69}')
+        )
+        assert response.get_json() == {
+            "item": {"is_offer": None, "name": "rolo", "price": 420.69},
+            "item_id": "123",
+        }