You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: pspm_get_mat_test.m
    path of file: ./repos/PsPM/test
    
    the code of the file until where you have to start completion: classdef pspm_get_mat_test < pspm_get_superclass
  % ● Description
  % unittest class for the pspm_get_mat function
  % PsPM TestEnvironment
  
    
function del_testdata_files(this)
      delete(this.testcases{1}.pth);
      delete(this.testcases{2}.pth);
      this.testcases = [];
    end
  end
  methods (Test)
    function invalid_datafile(this)
      fn = 'testfile_get_mat_test_3.mat';
      a = 3;
      save(fn, 'a');
      this.verifyWarning(@()pspm_get_mat(fn, this.testcases{1}.import), ...
      'ID:invalid_data_structure', 'invalid_datafile test 1');
      data = 'string';
      save(fn, 'data');
      this.verifyWarning(@()pspm_get_mat(fn, this.testcases{1}.import), ...
      'ID:invalid_data_structure', 'invalid_datafile test 2');
      data = cell(2,1);
      data{1} = ones(50,1);
      data{2} = ones(50,2);
      save(fn, 'data');
      this.verifyWarning(@()pspm_get_mat(fn, this.testcases{1}.import), ...
      'ID:invalid_data_structure', 'invalid_datafile test 3');
      delete(fn);
      fn = this.testcases{2}.pth;
      import{1} = struct('type', 'scr'   , 'channel', 1);
      import{2} = struct('type', 'marker', 'channel', 6);
      import = this.assign_chantype_number(import);
      this.verifyWarning(@()pspm_get_mat(fn, import), 'ID:channel_not_contained_in_file');
    end