TST: fix test_convert_dtypes for PANDAS_FUTURE_INFER_STRING=0

When using_infer_string is False, string columns start as object dtype
and get converted to Arrow, so memory is not shared.

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Co-Authored-By: Claude Opus 4.5 <[email protected]>

Author: fangchenli

pandas/tests/copy_view/test_astype.py

@@ -216,7 +216,12 @@ def test_convert_dtypes(using_infer_string):
     df_orig = df.copy()
     df2 = df.convert_dtypes()
 
-    assert tm.shares_memory(get_array(df2, "a"), get_array(df, "a"))
+    if using_infer_string:
+        # String column is already Arrow-backed, so memory is shared
+        assert tm.shares_memory(get_array(df2, "a"), get_array(df, "a"))
+    else:
+        # String column converts from object to Arrow, no memory sharing
+        assert not tm.shares_memory(get_array(df2, "a"), get_array(df, "a"))
     assert tm.shares_memory(get_array(df2, "d"), get_array(df, "d"))
     assert tm.shares_memory(get_array(df2, "b"), get_array(df, "b"))
     assert tm.shares_memory(get_array(df2, "c"), get_array(df, "c"))