Question

I have a testing framework where each test is an M file (for instance, test_featureX.m) that makes assertions to an instance of a special (custom) AssertionCollection class. Users will run tests individually when developing their features and may want to print useful information to the console during the test that will help them debug their problems. I also have a routine testAll that runs all tests for the entire repository and prints results in a standardized way. During this latter usage, I don’t want any extraneous information printed to the console, so the test executions are wrapped in evalc (evalc(‘test_featureX(ac);’)) which hides any console writes test_featureX makes.

Now, I would like testAll to print to screen in real time every time an assertion is made. I want to do this by adding a callback function to the AssertionClass instance (ac) before passing it to test_featureX, and having that callback function print an update on each assertion that passes. The problem is that the callback function is executed from within the call stack that originates in the evalc command, so its output is routed to the evalc string rather than the console.

Is there any way to force output to the console, even during an evalc evaluation, so that my callback can print statuses to the console while testAll rejects most standard writing to the console?

I’m hoping a result might look like:

s = evalc('testFunction();')
function testFunction()
    disp('line 1');
    fprintf('line 2\n');
    fprintf(TO_THE_CONSOLE, 'line 3\n');
end

…and the resulting output would be

line 3
  s =
    line 1
    line 2

Answer 1

I do not think it is possible. evalc captures everything except errors. Your best bet would be to add a return argument to testFunction and display that if needed.