test(JSONObjectAgg): add option to run tests on postgresql

pyproject.toml

@@ -22,14 +22,15 @@ Changelog = "https://github.com/quipucords/django-json-agg/releases"
 python = "^3.8"
 django = ">=4.2"
 
-[tool.poetry.group.dev.dependencies]
+[tool.poetry.group.devel.dependencies]
 Pygments = ">=2.10.0"
 coverage = { extras = ["toml"], version = ">=6.2" }
 faker = "^25.9.1"
 furo = ">=2021.11.12"
 myst-parser = { version = ">=0.16.1" }
 pre-commit = ">=2.16.0"
 pre-commit-hooks = ">=4.1.0"
+psycopg2 = "^2.9.9"
 pydoclint = "^0.4.1"
 pytest = ">=6.2.5"
 pytest-django = "^4.8.0"

tests/conftest.py

@@ -1,15 +1,32 @@
 """Testing setup."""
 
+from __future__ import annotations
+
 import django
+import pytest
+from django.conf import settings
+
+
+def pytest_addoption(parser: pytest.Parser):
+    parser.addoption("--db-vendor", action="store", default="sqlite")
+    parser.addoption("--db-name", action="store", default="postgres")
+    parser.addoption("--db-user", action="store", default="postgres")
+    parser.addoption("--db-password", action="store", default="")
+    parser.addoption("--db-host", action="store", default="127.0.0.1")
+    parser.addoption("--db-port", action="store", default="5432")
+
 
+@pytest.fixture(scope="session")
+def db_vendor(pytestconfig):
+    return pytestconfig.getoption("--db-vendor")
 
-def pytest_configure(config):
-    from django.conf import settings
 
+def pytest_configure(config: pytest.Config):
+    db_settings = get_db_settings(config)
     settings.configure(
         DEBUG_PROPAGATE_EXCEPTIONS=True,
         DATABASES={
-            "default": {"ENGINE": "django.db.backends.sqlite3", "NAME": ":memory:"},
+            "default": db_settings,
         },
         SITE_ID=1,
         SECRET_KEY="not a secret in tests",  # noqa: S106
@@ -45,3 +62,26 @@ def pytest_configure(config):
     )
 
     django.setup()
+
+
+def get_db_settings(config: pytest.Config):
+    valid_db_vendors = ["sqlite", "postgresql"]
+    vendor_name = config.getoption("--db-vendor")
+    if vendor_name not in valid_db_vendors:
+        raise pytest.UsageError(
+            f"Invalid db vendor ('{vendor_name}'). Valid values are {valid_db_vendors}."
+        )
+    settings_per_vendor = {
+        "sqlite": {"ENGINE": "django.db.backends.sqlite3", "NAME": ":memory:"},
+        "postgresql": {
+            "ENGINE": "django.db.backends.postgresql",
+            "NAME": config.getoption("--db-name"),
+            "USER": config.getoption("--db-user"),
+            "PASSWORD": config.getoption("--db-password"),
+            "HOST": config.getoption("--db-host"),
+            "PORT": config.getoption("--db-port"),
+        },
+    }
+
+    db_settings = settings_per_vendor[vendor_name]
+    return db_settings

tests/test_obj_agg.py

@@ -2,13 +2,13 @@
 
 from __future__ import annotations
 
+import datetime
 from functools import partial
 from itertools import chain
 from typing import TYPE_CHECKING
 
 import pytest
 from django.db.models import DateTimeField
-from django.db.models import JSONField
 
 from json_agg import JSONObjectAgg
 from tests.models import Author
@@ -116,12 +116,17 @@ def test_aggregate_text(faker: Faker):
 
 
 @pytest.mark.django_db
-def test_aggregate_datetime(faker: Faker):
+def test_aggregate_datetime(faker: Faker, db_vendor: str):
     """Test JSONObjectAgg over a datetime value (Post.updated_at)."""
+    kw = {}
+    if db_vendor == "postgresql":
+        # enforce tz for postgresql only - sqlite don't support it.
+        kw = dict(tzinfo=datetime.UTC)
+
     expected_value_per_author_name = post_factory(
         faker,
         value_name="updated_at",
-        value_factory=partial(faker.date_time),
+        value_factory=partial(faker.date_time, **kw),
     )
 
     queryset = Author.objects.annotate(
@@ -142,13 +147,17 @@ def test_aggregate_json(faker: Faker):
         value_name="metadata",
         value_factory=partial(faker.pydict, allowed_types=(str, int)),
     )
-
+    # we can't use nested_output_field for JSONField because it would only work
+    # for sqlite, which internally stores json as text. On postgres, data is
+    # stored as jsonb, which is automatically translated to dict (maybe by psycopg2?).
+    # This distinction on how those objects are stored internally breaks JSONField
+    # default decoder, which doesn't expect dicts.
     queryset = Author.objects.annotate(
         post_metadata=JSONObjectAgg(
             "posts__title",
             "posts__metadata",
-            nested_output_field=JSONField(),
-            # sqlite_func="json",
+            # nested_output_field=JSONField(),
+            sqlite_func="json",
         )
     ).all()