tests: use datetime.now() with timezone to handle DST correctly (#531)

* tests: use datetime.now() to ensure DST is handled correctly

* 🦉 Updates from OwlBot

See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md

* test: change fixture scope

* 🦉 Updates from OwlBot

See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md

Co-authored-by: larkee <[email protected]>
Co-authored-by: Owl Bot <gcf-owl-bot[bot]@users.noreply.github.com>

Author: larkee

tests/system/test_backup_api.py

@@ -79,9 +79,9 @@ def diff_config_instance(
     _helpers.scrub_instance_ignore_not_found(diff_config_instance)
 
 
-@pytest.fixture(scope="session")
-def database_version_time():
-    return datetime.datetime.utcnow().replace(tzinfo=datetime.timezone.utc)
+@pytest.fixture(scope="function")
+def database_version_time(shared_database):  # Ensure database exists.
+    return datetime.datetime.now(datetime.timezone.utc)
 
 
 @pytest.fixture(scope="session")
@@ -124,8 +124,9 @@ def test_backup_workflow(
     )
 
     backup_id = _helpers.unique_id("backup_id", separator="_")
-    expire_time = datetime.datetime.utcnow() + datetime.timedelta(days=3)
-    expire_time = expire_time.replace(tzinfo=datetime.timezone.utc)
+    expire_time = datetime.datetime.now(datetime.timezone.utc) + datetime.timedelta(
+        days=3
+    )
     encryption_enum = CreateBackupEncryptionConfig.EncryptionType
     encryption_config = CreateBackupEncryptionConfig(
         encryption_type=encryption_enum.GOOGLE_DEFAULT_ENCRYPTION,
@@ -162,8 +163,9 @@ def test_backup_workflow(
     )
 
     # Update with valid argument.
-    valid_expire_time = datetime.datetime.utcnow() + datetime.timedelta(days=7)
-    valid_expire_time = valid_expire_time.replace(tzinfo=datetime.timezone.utc)
+    valid_expire_time = datetime.datetime.now(
+        datetime.timezone.utc
+    ) + datetime.timedelta(days=7)
     backup.update_expire_time(valid_expire_time)
     assert valid_expire_time == backup.expire_time
 
@@ -193,15 +195,12 @@ def test_backup_workflow(
 
 
 def test_backup_create_w_version_time_dflt_to_create_time(
-    shared_instance,
-    shared_database,
-    database_version_time,
-    backups_to_delete,
-    databases_to_delete,
+    shared_instance, shared_database, backups_to_delete, databases_to_delete,
 ):
     backup_id = _helpers.unique_id("backup_id", separator="_")
-    expire_time = datetime.datetime.utcnow() + datetime.timedelta(days=3)
-    expire_time = expire_time.replace(tzinfo=datetime.timezone.utc)
+    expire_time = datetime.datetime.now(datetime.timezone.utc) + datetime.timedelta(
+        days=3
+    )
 
     # Create backup.
     backup = shared_instance.backup(
@@ -228,7 +227,7 @@ def test_backup_create_w_version_time_dflt_to_create_time(
 
 def test_backup_create_w_invalid_expire_time(shared_instance, shared_database):
     backup_id = _helpers.unique_id("backup_id", separator="_")
-    expire_time = datetime.datetime.utcnow().replace(tzinfo=datetime.timezone.utc)
+    expire_time = datetime.datetime.now(datetime.timezone.utc)
 
     backup = shared_instance.backup(
         backup_id, database=shared_database, expire_time=expire_time
@@ -243,10 +242,12 @@ def test_backup_create_w_invalid_version_time_past(
     shared_instance, shared_database,
 ):
     backup_id = _helpers.unique_id("backup_id", separator="_")
-    expire_time = datetime.datetime.utcnow() + datetime.timedelta(days=3)
-    expire_time = expire_time.replace(tzinfo=datetime.timezone.utc)
-    version_time = datetime.datetime.utcnow() - datetime.timedelta(days=10)
-    version_time = version_time.replace(tzinfo=datetime.timezone.utc)
+    expire_time = datetime.datetime.now(datetime.timezone.utc) + datetime.timedelta(
+        days=3
+    )
+    version_time = datetime.datetime.now(datetime.timezone.utc) - datetime.timedelta(
+        days=10
+    )
 
     backup = shared_instance.backup(
         backup_id,
@@ -264,10 +265,12 @@ def test_backup_create_w_invalid_version_time_future(
     shared_instance, shared_database,
 ):
     backup_id = _helpers.unique_id("backup_id", separator="_")
-    expire_time = datetime.datetime.utcnow() + datetime.timedelta(days=3)
-    expire_time = expire_time.replace(tzinfo=datetime.timezone.utc)
-    version_time = datetime.datetime.utcnow() + datetime.timedelta(days=2)
-    version_time = version_time.replace(tzinfo=datetime.timezone.utc)
+    expire_time = datetime.datetime.now(datetime.timezone.utc) + datetime.timedelta(
+        days=3
+    )
+    version_time = datetime.datetime.now(datetime.timezone.utc) + datetime.timedelta(
+        days=2
+    )
 
     backup = shared_instance.backup(
         backup_id,
@@ -289,8 +292,9 @@ def test_database_restore_to_diff_instance(
     databases_to_delete,
 ):
     backup_id = _helpers.unique_id("backup_id", separator="_")
-    expire_time = datetime.datetime.utcnow() + datetime.timedelta(days=3)
-    expire_time = expire_time.replace(tzinfo=datetime.timezone.utc)
+    expire_time = datetime.datetime.now(datetime.timezone.utc) + datetime.timedelta(
+        days=3
+    )
 
     # Create backup.
     backup = shared_instance.backup(
@@ -322,8 +326,9 @@ def test_multi_create_cancel_update_error_restore_errors(
 ):
     backup_id_1 = _helpers.unique_id("backup_id1", separator="_")
     backup_id_2 = _helpers.unique_id("backup_id2", separator="_")
-    expire_time = datetime.datetime.utcnow() + datetime.timedelta(days=3)
-    expire_time = expire_time.replace(tzinfo=datetime.timezone.utc)
+    expire_time = datetime.datetime.now(datetime.timezone.utc) + datetime.timedelta(
+        days=3
+    )
 
     backup1 = shared_instance.backup(
         backup_id_1, database=shared_database, expire_time=expire_time
@@ -354,8 +359,8 @@ def test_multi_create_cancel_update_error_restore_errors(
 
     # Update expire time to invalid value.
     max_expire_days = 366  # documented maximum
-    invalid_expire_time = datetime.datetime.now().replace(
-        tzinfo=datetime.timezone.utc
+    invalid_expire_time = datetime.datetime.now(
+        datetime.timezone.utc
     ) + datetime.timedelta(days=max_expire_days + 1)
     with pytest.raises(exceptions.InvalidArgument):
         backup1.update_expire_time(invalid_expire_time)
@@ -385,8 +390,9 @@ def test_instance_list_backups(
     backup_id_1 = _helpers.unique_id("backup_id1", separator="_")
     backup_id_2 = _helpers.unique_id("backup_id2", separator="_")
 
-    expire_time_1 = datetime.datetime.utcnow() + datetime.timedelta(days=21)
-    expire_time_1 = expire_time_1.replace(tzinfo=datetime.timezone.utc)
+    expire_time_1 = datetime.datetime.now(datetime.timezone.utc) + datetime.timedelta(
+        days=21
+    )
     expire_time_1_stamp = expire_time_1.strftime("%Y-%m-%dT%H:%M:%S.%fZ")
 
     backup1 = shared_instance.backup(
@@ -396,8 +402,9 @@ def test_instance_list_backups(
         version_time=database_version_time,
     )
 
-    expire_time_2 = datetime.datetime.utcnow() + datetime.timedelta(days=1)
-    expire_time_2 = expire_time_2.replace(tzinfo=datetime.timezone.utc)
+    expire_time_2 = datetime.datetime.now(datetime.timezone.utc) + datetime.timedelta(
+        days=1
+    )
     backup2 = shared_instance.backup(
         backup_id_2, database=second_database, expire_time=expire_time_2
     )
@@ -408,9 +415,7 @@ def test_instance_list_backups(
     op1.result()  # blocks indefinitely
     backup1.reload()
 
-    create_time_compare = datetime.datetime.utcnow().replace(
-        tzinfo=datetime.timezone.utc
-    )
+    create_time_compare = datetime.datetime.now(datetime.timezone.utc)
     create_time_stamp = create_time_compare.strftime("%Y-%m-%dT%H:%M:%S.%fZ")
 
     backup2.create()