fixup test_impl

Author: MarcoGorelli

pandas/tests/interchange/test_impl.py

@@ -7,6 +7,8 @@
 from pandas._libs.tslibs import iNaT
 import pandas.util._test_decorators as td
 
+from pandas.core.dtypes.common import is_float_dtype
+
 import pandas as pd
 import pandas._testing as tm
 from pandas.core.interchange.column import PandasColumn
@@ -115,7 +117,12 @@ def test_missing_from_masked():
         null_idx = df.index[
             rng.choice(np.arange(len(df)), size=num_nulls, replace=False)
         ]
-        df.loc[null_idx, col] = None
+        if is_float_dtype(df[col]):
+            warn = None
+        else:
+            warn = FutureWarning
+        with tm.assert_produces_warning(warn, match="item of incompatible dtype"):
+            df.loc[null_idx, col] = None
 
     df2 = df.__dataframe__()