code: def test_plot_fit(self, close_figures):
      res = self.res
  
      fig = plot_fit(res, 0, y_true=None)
  
      x0 = res.model.exog[:, 0]
      yf = res.fittedvalues
      y = res.model.endog
  
      px1, px2 = fig.axes[0].get_lines()[0].get_data()
      np.testing.assert_equal(x0, px1)
      np.testing.assert_equal(y, px2)
  
      px1, px2 = fig.axes[0].get_lines()[1].get_data()
      np.testing.assert_equal(x0, px1)
      np.testing.assert_equal(yf, px2)
  
      close_or_save(pdf, fig)
  
imports: import numpy
  from numpy.testing import assert_array_less, assert_equal, assert_raises
  from pandas import DataFrame, Series
  import pytest
  import statsmodels.api
  from statsmodels.graphics.regressionplots import abline_plot, add_lowess, influence_plot, plot_added_variable, plot_ccpr, plot_ccpr_grid, plot_ceres_residuals, plot_fit, plot_leverage_resid2, plot_partial_residuals, plot_partregress_grid, plot_regress_exog
label_desc: Use image node_id 2 for calling the TestPlot obj's underlying member method code with example usage: obj.test_plot_fit(close_figures) without return types