Correctly add default values to created pydantic models

piccolo_api/crud/serializers.py

@@ -50,6 +50,10 @@ def create_pydantic_model(
     """
     Create a Pydantic model representing a table.
 
+    Make sure that you are using the ``required`` attribute on each ``Field``
+    of your model because it is used here to find out whether each created
+    Pydantic field should have a default value or not.
+
     :param table:
         The Piccolo ``Table`` you want to create a Pydantic serialiser model
         for.
@@ -131,9 +135,10 @@ def create_pydantic_model(
         #######################################################################
 
         params: t.Dict[str, t.Any] = {
-            "default": None if is_optional else ...,
             "nullable": column._meta.null,
         }
+        if not column._meta.required:
+            params.update({"default_factory": column.get_default_value})
 
         extra = {
             "help_text": column._meta.help_text,

tests/crud/test_crud_endpoints.py

@@ -870,8 +870,14 @@ def test_new(self):
 
         response = client.get("/new/")
         self.assertEqual(response.status_code, 200)
+        response_json = response.json()
+        self.assertEqual(
+            response_json["name"],
+            "",
+        )
         self.assertEqual(
-            response.json(), {"id": None, "name": "", "rating": 0}
+            response_json["rating"],
+            0,
         )
 
 

tests/crud/test_serializers.py

@@ -2,7 +2,7 @@
 from unittest import TestCase
 
 import pydantic
-from piccolo.columns import Array, Numeric, Text, Varchar
+from piccolo.columns import Array, Integer, Numeric, Text, Varchar
 from piccolo.columns.column_types import JSON, JSONB, Secret
 from piccolo.table import Table
 from pydantic import ValidationError
@@ -256,3 +256,50 @@ class Computer2(Table):
 
         with self.assertRaises(ValueError):
             create_pydantic_model(Computer, exclude_columns=(Computer2.CPU,))
+
+
+class TestDefaultColumn(TestCase):
+    def test_default(self):
+        class Monitor(Table):
+            refresh_rate = Integer(default=144)
+            resolution = Varchar(required=True)
+
+        pydantic_model = create_pydantic_model(Monitor)
+
+        assert pydantic_model.schema()["required"] == ["resolution"]
+
+        pydantic_instance = pydantic_model(resolution="1440*2560")
+
+        assert pydantic_instance.refresh_rate == 144
+        assert pydantic_instance.resolution == "1440*2560"
+
+    def test_default_factory(self):
+        class Monitor(Table):
+            refresh_rate = Integer(required=True)
+            resolution = Varchar(default=lambda: "1920*1080")
+
+        pydantic_model = create_pydantic_model(Monitor)
+
+        assert pydantic_model.schema()["required"] == ["refresh_rate"]
+
+        pydantic_instance = pydantic_model(refresh_rate=60)
+
+        assert pydantic_instance.refresh_rate == 60
+        assert pydantic_instance.resolution == "1920*1080"
+
+    def test_override_default(self):
+        class Monitor(Table):
+            refresh_rate = Integer(default=240)
+            resolution = Varchar(default=lambda: "1440*2560")
+
+        pydantic_model = create_pydantic_model(Monitor)
+
+        assert not pydantic_model.schema().get("required")
+
+        pydantic_instance = pydantic_model(
+            refresh_rate=60,
+            resolution="1080*1920",
+        )
+
+        assert pydantic_instance.refresh_rate == 60
+        assert pydantic_instance.resolution == "1080*1920"

tests/fastapi/test_fastapi_endpoints.py

@@ -111,9 +111,14 @@ def test_get_responses(self):
 
         response = client.get("/movies/new/")
         self.assertEqual(response.status_code, 200)
+        response_json = response.json()
         self.assertEqual(
-            response.json(),
-            {"id": None, "name": "", "rating": 0},
+            response_json["name"],
+            "",
+        )
+        self.assertEqual(
+            response_json["rating"],
+            0,
         )
 
         response = client.get("/movies/references/")