tests.testlib: bugfix in site.Site; enables usage of REUSE=1.

Skip creation of (existing) automation user within an existing site
, when REUSE=1.

Details:

During a (system) test-run in the site creation stage,
a new automation user is being created.

When tests are re-run using `REUSE=1`, the site-creation is skipped
BUT the automation user creation is not. This led to a pytest run
failure, as the user already existed.

CMK-21035

Change-Id: I8352872e0766b32792999794916a14914e96a15b

tests/testlib/site.py

@@ -1134,10 +1134,9 @@ def core_history_log(self) -> Path:
     def core_history_log_timeout(self) -> int:
         return 10 if self.core_name() == "cmc" else 30
 
-    def _create_automation_user(self) -> None:
-        username = AUTOMATION_USER
+    def _create_automation_user(self, username: str) -> None:
         self._automation_secret = Password.random(24)
-
+        logger.info("Creating test-user: '%s'.", username)
         self.openapi.users.create(
             username=username,
             fullname="Automation user for tests",
@@ -1152,7 +1151,11 @@ def _create_automation_user(self) -> None:
     @tracer.start_as_current_span("Site.prepare_for_tests")
     def prepare_for_tests(self) -> None:
         logger.info("Prepare for tests")
-        self._create_automation_user()
+        username = AUTOMATION_USER
+        if self.openapi.users.get(username) is None:
+            self._create_automation_user(username)
+        else:
+            logger.info("Reusing existing test-user: '%s' (REUSE=1).", username)
         if self.enforce_english_gui:
             web = CMKWebSession(self)
             if not self.version.is_saas_edition():