tests fixing

Author: chelsea-lin

db_dtypes/__init__.py

@@ -338,18 +338,6 @@ def __sub__(self, other):
         return super().__sub__(other)
 
 
-sys_major, sys_minor, sys_micro = _versions_helpers.extract_runtime_version()
-if sys_major == 3 and sys_minor in (7, 8):
-    warnings.warn(
-        "The python-bigquery library will stop supporting Python 3.7 "
-        "and Python 3.8 in a future major release expected in Q4 2024. "
-        f"Your Python version is {sys_major}.{sys_minor}.{sys_micro}. We "
-        "recommend that you update soon to ensure ongoing support. For "
-        "more details, see: [Google Cloud Client Libraries Supported Python Versions policy](https://cloud.google.com/python/docs/supported-python-versions)",
-        PendingDeprecationWarning,
-    )
-
-
 __all__ = [
     "__version__",
     "DateArray",

noxfile.py

@@ -32,7 +32,7 @@
 ISORT_VERSION = "isort==5.11.0"
 LINT_PATHS = ["docs", "db_dtypes", "tests", "noxfile.py", "setup.py"]
 
-DEFAULT_PYTHON_VERSION = "3.9"
+DEFAULT_PYTHON_VERSION = "3.10"
 
 UNIT_TEST_PYTHON_VERSIONS: List[str] = ["3.9", "3.10", "3.11", "3.12"]
 UNIT_TEST_STANDARD_DEPENDENCIES = [