docstr: Test that acquisition function returns correct weighted acquisition
          
docstr_tok: ["Test","that","acquisition","function","returns","correct","weighted","acquisition"]
code: def test_acquisition_function(self):
      """Test that acquisition function returns correct weighted acquisition"""
      self.mock_model.predict.return_value = (1, 3)
      self.mock_model.get_fmin.return_value = 0.1
  
      weighted_acquisition = self.ei_acquisition.acquisition_function(
          np.array([2, 2])
      )
  
      assert np.isclose(
          weighted_acquisition, np.array([[-0.79646919], [-0.79646919]])
      ).all()
  
file_path: GPyOpt/GPyOpt/testing/acquisitions_tests/test_ei_acquisition.py
imports: import unittest
  from mock import Mock
  import numpy
  from GPyOpt.acquisitions import AcquisitionEI
  from GPyOpt.core.task.space import Design_space
label_desc: Use image node_id 2 for calling the TestEIAcquisition obj's underlying member method code with example usage: obj.test_acquisition_function() without return types