code: def test_interp_scipy_basic(self):
      pytest.importorskip("scipy")
      s = Series([1, 3, np.nan, 12, np.nan, 25])
      # slinear
      expected = Series([1.0, 3.0, 7.5, 12.0, 18.5, 25.0])
      result = s.interpolate(method="slinear")
      tm.assert_series_equal(result, expected)
  
      msg = "The 'downcast' keyword in Series.interpolate is deprecated"
      with tm.assert_produces_warning(FutureWarning, match=msg):
          result = s.interpolate(method="slinear", downcast="infer")
      tm.assert_series_equal(result, expected)
      # nearest
      expected = Series([1, 3, 3, 12, 12, 25])
      result = s.interpolate(method="nearest")
      tm.assert_series_equal(result, expected.astype("float"))
  
      with tm.assert_produces_warning(FutureWarning, match=msg):
          result = s.interpolate(method="nearest", downcast="infer")
      tm.assert_series_equal(result, expected)
      # zero
      expected = Series([1, 3, 3, 12, 12, 25])
      result = s.interpolate(method="zero")
      tm.assert_series_equal(result, expected.astype("float"))
  
      with tm.assert_produces_warning(FutureWarning, match=msg):
          result = s.interpolate(method="zero", downcast="infer")
      tm.assert_series_equal(result, expected)
      # quadratic
      # GH #15662.
      expected = Series([1, 3.0, 6.823529, 12.0, 18.058824, 25.0])
      result = s.interpolate(method="quadratic")
      tm.assert_series_equal(result, expected)
  
      with tm.assert_produces_warning(FutureWarning, match=msg):
          result = s.interpolate(method="quadratic", downcast="infer")
      tm.assert_series_equal(result, expected)
      # cubic
      expected = Series([1.0, 3.0, 6.8, 12.0, 18.2, 25.0])
      result = s.interpolate(method="cubic")
      tm.assert_series_equal(result, expected)
  
imports: import numpy
  import pytest
  import pandas.util._test_decorators
  import pandas
  from pandas import Index, MultiIndex, Series, date_range, isna
  import pandas._testing
label_desc: Use image node_id 16 for calling the TestSeriesInterpolateData obj's underlying member method code with example usage: obj.test_interp_scipy_basic() without return types