Fix mac unit test by skipping mac runtime on runners < macOS15 (#19615)

Author: metascroy

devtools/intermediate_output_tap/tests/test_coreml_e2e.py

@@ -23,6 +23,7 @@
 
 import math
 import os
+import platform
 import sys
 import tempfile
 import types
@@ -83,6 +84,23 @@ def _assert_df_quality(
             )
 
 
+def _macos_version() -> tuple[int, int]:
+    """Return (major, minor) macOS version, or (0, 0) on non-macOS."""
+    if sys.platform != "darwin":
+        return (0, 0)
+    release = platform.mac_ver()[0]
+    if not release:
+        return (0, 0)
+    parts = release.split(".")
+    major = int(parts[0]) if parts and parts[0].isdigit() else 0
+    minor = int(parts[1]) if len(parts) > 1 and parts[1].isdigit() else 0
+    return (major, minor)
+
+
+# iOS18 CoreML models require macOS 15+ to execute at runtime.
+_MACOS_SUPPORTS_IOS18_RUNTIME = _macos_version() >= (15, 0)
+
+
 def _print_df(df: pd.DataFrame, header: str) -> None:
     with pd.option_context(
         "display.max_columns",
@@ -240,6 +258,16 @@ def test_tap_compare_static_llama_coreml(self):
         with tempfile.TemporaryDirectory() as temp_dir:
             pte_path = os.path.join(temp_dir, "model.pte")
             et_program.save(pte_path)
+
+            # iOS18-targeted CoreML models require macOS 15+ at runtime; on
+            # older macOS we exercise AOT lowering + .pte serialization only
+            # and skip runtime execution and the AOT-vs-runtime comparison.
+            if not _MACOS_SUPPORTS_IOS18_RUNTIME:
+                self.skipTest(
+                    "Skipping runtime portion: iOS18 CoreML models require "
+                    f"macOS 15+, found macOS {platform.mac_ver()[0] or 'unknown'}"
+                )
+
             rt = Runtime.get()
             program = rt.load_program(pte_path, verification=Verification.Minimal)
             method = program.load_method("forward")