code: def test_ewm_corr_cov_min_periods(name, min_periods):
      # GH 7898
      A = Series(
          np.random.default_rng(2).standard_normal(50), index=range(50)
      )
      B = A[2:] + np.random.default_rng(2).standard_normal(48)
  
      A[:10] = np.nan
      B.iloc[-10:] = np.nan
  
      result = getattr(A.ewm(com=20, min_periods=min_periods), name)(B)
      # binary functions (ewmcov, ewmcorr) with bias=False require at
      # least two values
      assert np.isnan(result.values[:11]).all()
      assert not np.isnan(result.values[11:]).any()
  
      # check series of length 0
      empty = Series([], dtype=np.float64)
      result = getattr(
          empty.ewm(com=50, min_periods=min_periods), name
      )(empty)
      tm.assert_series_equal(result, empty)
  
      # check series of length 1
      result = getattr(
          Series([1.0]).ewm(com=50, min_periods=min_periods), name
      )(Series([1.0]))
      tm.assert_series_equal(result, Series([np.nan]))
  
imports: import numpy
  import pytest
  from pandas import DataFrame, DatetimeIndex, Series, date_range
  import pandas._testing
label_desc: Use image node_id 26 for calling a global function with example usage: test_ewm_corr_cov_min_periods(name, min_periods) without return types