code: def test_to_csv():
      """Test converting between Dataset and CSV"""
      tmpdir = tempfile.TemporaryDirectory()
      csv_path = os.path.join(tmpdir.name, "tmp.csv")
  
      dataset = load_solubility_data()
      dataset.reshard(2)
      dataset.to_csv(csv_path)
  
      df = pd.read_csv(csv_path)
      dataset2 = dc.data.Dataset.from_dataframe(df)
      np.testing.assert_array_equal(dataset.X, dataset2.X)
      np.testing.assert_array_equal(dataset.y, dataset2.y)
      np.testing.assert_array_equal(dataset.w, dataset2.w)
      np.testing.assert_array_equal(dataset.ids, dataset2.ids)
  
      # Try specifying particular columns
      dataset3 = dc.data.Dataset.from_dataframe(
          df, X=["X2", "X4"], y="w", w=["y", "X1"]
      )
      np.testing.assert_array_equal(dataset.X[:, (1, 3)], dataset3.X)
      np.testing.assert_array_equal(dataset.w, dataset3.y)
      np.testing.assert_array_equal(
          np.stack([dataset.y[:, 0], dataset.X[:, 0]], axis=1),
          dataset3.w,
      )
  
      x = np.array([np.random.randn(2, 3), np.random.randn(2, 3)])
      dataset = dc.data.NumpyDataset(X=x, y=np.array([[1], [2]]))
      with pytest.raises(AssertionError):
          dataset.to_csv(csv_path)
  
imports: import random
  import math
  import unittest
  import os
  import numpy
  import pytest
  import deepchem
  import pandas
  import tempfile
label_desc: Use image node_id 27 for calling a global function with example usage: test_to_csv() without return types