diff --git a/lldb/packages/Python/lldbsuite/test/decorators.py b/lldb/packages/Python/lldbsuite/test/decorators.py
--- a/lldb/packages/Python/lldbsuite/test/decorators.py
+++ b/lldb/packages/Python/lldbsuite/test/decorators.py
@@ -538,10 +538,9 @@
 def skipIfRosetta(bugnumber):
     """Skip a test when running the testsuite on macOS under the Rosetta translation layer."""
     def is_running_rosetta(self):
-        if not lldbplatformutil.getPlatform() in ['darwin', 'macosx']:
-            return "not on macOS"
-        if (platform.uname()[5] == "arm") and (self.getArchitecture() == "x86_64"):
-            return "skipped under Rosetta"
+        if lldbplatformutil.getPlatform() in ['darwin', 'macosx']:
+            if (platform.uname()[5] == "arm") and (self.getArchitecture() == "x86_64"):
+                return "skipped under Rosetta"
         return None
     return skipTestIfFn(is_running_rosetta)