error stack trace visible with verifyError

Hello all,

How can I make my test running silently when using a VerifyError which checks an error is occurring? Now it displays the entire exception trace.

My testcase is defined as:

          function testcaseFHwrong(testCase)
              cd(testCase.foldername);
              try
                  testCase.verifyError(@() LoadFaultTable('Faulttablewrong.xls','SilentMode',1),'readfaulttable:NoFaultTable');
              catch ME
                  disp(ME);
                  testCase.verifyTrue(False);
              end
          end

The function LoadFaultTable will issue an error when being run, and this error is correctly verified by the unit test framework.

The unit test is triggered using:

import matlab.unittest.TestSuite;
import matlab.unittest.TestRunner;
import matlab.unittest.plugins.TAPPlugin;
import matlab.unittest.plugins.ToFile;

suite = TestSuite.fromPackage('test_LIB_SDS_LoadFaultTable');
runner= TestRunner.withTextOutput;
tapFile = 'FHtest.tap';
plugin = TAPPlugin.producingOriginalFormat(ToFile(tapFile));
runner.addPlugin(plugin);
delete(tapFile);
result = runner.run(suite);

The command line shows the error stack trace when running this function. I did not expect this behavior

regards, Han

Answer 1

[Andy Campbell]

Hi Hans,

I think that there is still some key ingredient missing. I wrote the following stub for LoadFaultTable:

    function LoadFaultTable(varargin)

    error('readfaulttable:NoFaultTable', 'Something went wrong');

With the following surrounding test:

 classdef ErrorTest < matlab.unittest.TestCase

     properties
         foldername = '.';
     end

     methods(Test)

         function testcaseFHwrong(testCase)
               cd(testCase.foldername);
               try
                   testCase.verifyError(@() LoadFaultTable('Faulttablewrong.xls', ...
                       'SilentMode',1),'readfaulttable:NoFaultTable');
               catch ME
                   disp(ME);
                   testCase.verifyTrue(False);
               end
         end
     end
 end

...and the output looks fine:

 >> runtests
 Running ErrorTest
 .
 Done ErrorTest
 __________

 ans = 

   TestResult with properties:

           Name: 'ErrorTest/testcaseFHwrong'
         Passed: 1
         Failed: 0
     Incomplete: 0
       Duration: 0.011415858

 Totals:
    1 Passed, 0 Failed, 0 Incomplete.
    0.011416 seconds testing time.

I think there is still something else at play here. Is the source code (LoadFaultTable) the thing which is printing the stack trace? Can you show the stack trace? Perhaps the call to CD removes the source and/or test from the path (here the cd is basically a no-op)?

Also, did you put the try-catch in there as a debugging step? Typically you don't need to use a try-catch when using the Throws constraint or verifyError. Taking out the try-catch produces the same expected, empty output when running the test.

[Han Geerligs]

Hello Andy,

thanks for the prompt response.

I was using a try catch construction. In the catch I was issueing an error report using disp(getReport(ME)). This was causing the stack trace. Your answer got me on track to identify this issue.

regards, Han