code: def test_groupby_quantile_allNA_column(dtype):
      # GH#42849
      df = DataFrame({"x": [1, 1], "y": [pd.NA] * 2}, dtype=dtype)
      result = df.groupby("x")["y"].quantile(0.5)
      expected = pd.Series(
          [np.nan],
          dtype=dtype,
          index=Index([1.0], dtype=dtype),
          name="y",
      )
      expected.index.name = "x"
      tm.assert_series_equal(expected, result)
  
imports: import numpy
  import pytest
  import pandas
  from pandas import DataFrame, Index
  import pandas._testing
label_desc: Use image node_id 17 for calling a global function with example usage: test_groupby_quantile_allNA_column(dtype) without return types