make sure ModeBuilder generates tz aware values for Timestamptz (#…

…923)

piccolo/columns/column_types.py

@@ -1005,6 +1005,11 @@ class Concert(Table):
     """
 
     value_type = datetime
+
+    # Currently just used by ModelBuilder, to know that we want a timezone
+    # aware datetime.
+    tz_aware = True
+
     timedelta_delegate = TimedeltaDelegate()
 
     def __init__(

piccolo/testing/model_builder.py

@@ -1,8 +1,8 @@
 from __future__ import annotations
 
+import datetime
 import json
 import typing as t
-from datetime import date, datetime, time, timedelta
 from decimal import Decimal
 from uuid import UUID
 
@@ -16,13 +16,13 @@ class ModelBuilder:
     __DEFAULT_MAPPER: t.Dict[t.Type, t.Callable] = {
         bool: RandomBuilder.next_bool,
         bytes: RandomBuilder.next_bytes,
-        date: RandomBuilder.next_date,
-        datetime: RandomBuilder.next_datetime,
+        datetime.date: RandomBuilder.next_date,
+        datetime.datetime: RandomBuilder.next_datetime,
         float: RandomBuilder.next_float,
         int: RandomBuilder.next_int,
         str: RandomBuilder.next_str,
-        time: RandomBuilder.next_time,
-        timedelta: RandomBuilder.next_timedelta,
+        datetime.time: RandomBuilder.next_time,
+        datetime.timedelta: RandomBuilder.next_timedelta,
         UUID: RandomBuilder.next_uuid,
     }
 
@@ -155,6 +155,9 @@ def _randomize_attribute(cls, column: Column) -> t.Any:
             random_value = RandomBuilder.next_float(
                 maximum=10 ** (precision - scale), scale=scale
             )
+        elif column.value_type == datetime.datetime:
+            tz_aware = getattr(column, "tz_aware", False)
+            random_value = RandomBuilder.next_datetime(tz_aware=tz_aware)
         elif column.value_type == list:
             length = RandomBuilder.next_int(maximum=10)
             base_type = t.cast(Array, column).base_column.value_type

piccolo/testing/random_builder.py

@@ -1,9 +1,9 @@
+import datetime
 import enum
 import random
 import string
 import typing as t
 import uuid
-from datetime import date, datetime, time, timedelta
 
 
 class RandomBuilder:
@@ -16,22 +16,23 @@ def next_bytes(cls, length=8) -> bytes:
         return random.getrandbits(length * 8).to_bytes(length, "little")
 
     @classmethod
-    def next_date(cls) -> date:
-        return date(
+    def next_date(cls) -> datetime.date:
+        return datetime.date(
             year=random.randint(2000, 2050),
             month=random.randint(1, 12),
             day=random.randint(1, 28),
         )
 
     @classmethod
-    def next_datetime(cls) -> datetime:
-        return datetime(
+    def next_datetime(cls, tz_aware: bool = False) -> datetime.datetime:
+        return datetime.datetime(
             year=random.randint(2000, 2050),
             month=random.randint(1, 12),
             day=random.randint(1, 28),
             hour=random.randint(0, 23),
             minute=random.randint(0, 59),
             second=random.randint(0, 59),
+            tzinfo=datetime.timezone.utc if tz_aware else None,
         )
 
     @classmethod
@@ -53,16 +54,16 @@ def next_str(cls, length=16) -> str:
         )
 
     @classmethod
-    def next_time(cls) -> time:
-        return time(
+    def next_time(cls) -> datetime.time:
+        return datetime.time(
             hour=random.randint(0, 23),
             minute=random.randint(0, 59),
             second=random.randint(0, 59),
         )
 
     @classmethod
-    def next_timedelta(cls) -> timedelta:
-        return timedelta(
+    def next_timedelta(cls) -> datetime.timedelta:
+        return datetime.timedelta(
             days=random.randint(1, 7),
             hours=random.randint(1, 23),
             minutes=random.randint(0, 59),

tests/testing/test_model_builder.py

@@ -11,6 +11,8 @@
     LazyTableReference,
     Numeric,
     Real,
+    Timestamp,
+    Timestamptz,
     Varchar,
 )
 from piccolo.table import Table, create_db_tables_sync, drop_db_tables_sync
@@ -97,6 +99,25 @@ def test_choices(self):
             ["s", "l", "m"],
         )
 
+    def test_datetime(self):
+        """
+        Make sure that ``ModelBuilder`` generates timezone aware datetime
+        objects for ``Timestamptz`` columns, and timezone naive datetime
+        objects for ``Timestamp`` columns.
+        """
+
+        class Table1(Table):
+            starts = Timestamptz()
+
+        class Table2(Table):
+            starts = Timestamp()
+
+        model_1 = ModelBuilder.build_sync(Table1, persist=False)
+        assert model_1.starts.tzinfo is not None
+
+        model_2 = ModelBuilder.build_sync(Table2, persist=False)
+        assert model_2.starts.tzinfo is None
+
     def test_foreign_key(self):
         model = ModelBuilder.build_sync(Band, persist=True)