text: import pytest
  
  from janitor.utils import check_column
  
  
  @pytest.mark.utils
  def test_check_column(dataframe):
      """
      check_column should return if column exist
      """
      assert check_column(dataframe, ["a"]) is None
  
  
  @pytest.mark.utils
  def test_check_column_single(dataframe):
      """
      Check works with a single input
      """
  
      assert check_column(dataframe, "a") is None
  
      with pytest.raises(ValueError):
          check_column(dataframe, "b")
  
      # should also work with non-string inputs
  
      with pytest.raises(ValueError):
          check_column(dataframe, 2)
  
      dataframe[2] = "asdf"
  
      assert check_column(dataframe, 2) is None
  
  
  @pytest.mark.utils
  def test_check_column_absent_column(dataframe):
      """
      check_column should raise an error if the column is absent.
      """
      with pytest.raises(ValueError):
          check_column(dataframe, ["b"])
  
  
  @pytest.mark.utils
  def test_check_column_excludes(dataframe):
      """
      check_column should return if column is absent and present is False
      """
      assert check_column(dataframe, ["b"], present=False) is None
  
  
  @pytest.mark.utils
  def test_check_column_absent_column_excludes(dataframe):
      """
      check_column should raise an error if the column is absent and present is
      False
      """
      with pytest.raises(ValueError):
          check_column(dataframe, ["a"], present=False)
  