OP-3426 - refactor - replaced check of env var with function

It would be better to modify single function if necessary.

openpype/plugins/publish/cleanup.py

@@ -5,6 +5,8 @@ import shutil
 import pyblish.api
 import re
 
+from openpype.tests.lib import is_in_tests
+
 
 class CleanUp(pyblish.api.InstancePlugin):
     """Cleans up the staging directory after a successful publish.
@@ -44,7 +46,7 @@ class CleanUp(pyblish.api.InstancePlugin):
 
     def process(self, instance):
         """Plugin entry point."""
-        if os.environ.get("IS_TEST"):
+        if is_in_tests():
             # let automatic test process clean up temporary data
             return
         # Get the errored instances

openpype/plugins/publish/collect_scene_version.py

@@ -2,6 +2,7 @@ import os
 import pyblish.api
 
 from openpype.lib import get_version_from_path
+from openpype.tests.lib import is_in_tests
 
 
 class CollectSceneVersion(pyblish.api.ContextPlugin):
@@ -36,7 +37,7 @@ class CollectSceneVersion(pyblish.api.ContextPlugin):
         # tests should be close to regular publish as possible
         if (
             os.environ.get("HEADLESS_PUBLISH")
-            and not os.environ.get("IS_TEST")
+            and not is_in_tests()
             and context.data["hostName"] in self.skip_hosts_headless_publish):
             self.log.debug("Skipping for headless publishing")
             return