Sync from v0.13

tests/utils_/test_import_utils.py

@@ -0,0 +1,46 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+import pytest
+
+from vllm.utils.import_utils import PlaceholderModule
+
+
+def _raises_module_not_found():
+    return pytest.raises(ModuleNotFoundError, match="No module named")
+
+
+def test_placeholder_module_error_handling():
+    placeholder = PlaceholderModule("placeholder_1234")
+
+    with _raises_module_not_found():
+        int(placeholder)
+
+    with _raises_module_not_found():
+        placeholder()
+
+    with _raises_module_not_found():
+        _ = placeholder.some_attr
+
+    with _raises_module_not_found():
+        # Test conflict with internal __name attribute
+        _ = placeholder.name
+
+    # OK to print the placeholder or use it in a f-string
+    _ = repr(placeholder)
+    _ = str(placeholder)
+
+    # No error yet; only error when it is used downstream
+    placeholder_attr = placeholder.placeholder_attr("attr")
+
+    with _raises_module_not_found():
+        int(placeholder_attr)
+
+    with _raises_module_not_found():
+        placeholder_attr()
+
+    with _raises_module_not_found():
+        _ = placeholder_attr.some_attr
+
+    with _raises_module_not_found():
+        # Test conflict with internal __module attribute
+        _ = placeholder_attr.module