gui_e2e: make email notifications test more robust

Instead of asserting that the count is zero or not zero, let's take into
account the current stats before running the test. Now we are asserting
that the total notifications sent count has changed and the total
failures has remained the same.

This makes the test more robust because now notification failures from
other tests don't have an influence on what we are asserting in this
test.

CMK-21533

Change-Id: I79728f2929d83421518fadd4b4280f312e442367

tests/gui_e2e/test_email_notifications.py

@@ -53,6 +53,9 @@ def test_filesystem_email_notifications(
 
     logger.info("Clone the existing default notification rule")
     notification_configuration_page = NotificationConfiguration(dashboard_page.page)
+    total_sent = notification_configuration_page.get_total_sent_notifications_count()
+    total_failures = notification_configuration_page.get_failed_notifications_count()
+    logger.info("Current notification stats: sent=%s, failed=%s", total_sent, total_failures)
     # The scrollbar interrupts the interaction with rule edit button -> collapse overview
     notification_configuration_page.collapse_notification_overview(True)
     notification_configuration_page.notification_rule_copy_button(0).click()
@@ -112,8 +115,8 @@ def test_filesystem_email_notifications(
         notification_configuration_page.navigate()
         # The notifications stats need to be read -> open overview
         notification_configuration_page.collapse_notification_overview(False)
-        notification_configuration_page.check_total_sent_notifications_is_not_zero()
-        notification_configuration_page.check_failed_notifications_is_zero()
+        notification_configuration_page.check_total_sent_notifications_has_changed(total_sent)
+        notification_configuration_page.check_failed_notifications_has_not_changed(total_failures)
 
         with manage_new_page_from_browser_context(service_search_page.page.context) as new_page:
             email_page = EmailPage(new_page, html_file_path)

tests/gui_e2e/testlib/playwright/pom/setup/notification_configuration.py

@@ -108,10 +108,16 @@ def _get_notification_stat_count(self, title: str) -> Locator:
             .get_by_role("paragraph")
         )
 
-    def check_total_sent_notifications_is_not_zero(self) -> None:
+    def get_total_sent_notifications_count(self) -> int:
+        return int(self._get_notification_stat_count("Total sent notifications").inner_text())
+
+    def check_total_sent_notifications_has_changed(self, previous_count: int) -> None:
         locator = self._get_notification_stat_count("Total sent notifications")
-        expect(locator).not_to_have_text(re.compile(r"^0$"))  # "0" isn't valid
+        expect(locator).not_to_have_text(re.compile(rf"^{previous_count}$"))
+
+    def get_failed_notifications_count(self) -> int:
+        return int(self._get_notification_stat_count("Failed notifications").inner_text())
 
-    def check_failed_notifications_is_zero(self) -> None:
+    def check_failed_notifications_has_not_changed(self, previous_count: int) -> None:
         locator = self._get_notification_stat_count("Failed notifications")
-        expect(locator).to_have_text(re.compile(r"^\s0$"))  # " 0" is valid
+        expect(locator).to_have_text(re.compile(rf"^\s{previous_count}$"))