MATLAB: Produce a diagnistic once per failed test method

Question

Is it possible to produce a diagnostic once per failed test method (as opposed to once per verify/assert, which is what TestCase.onFailure does)?

A common scenario in my test code is that I read some input data, process it and make several testCase.verify… on the processed data. If one or more verifications fail, I wish to produce a diagnostic message with the input data, but only once per test method to not pollute the log.

Answer 1

I think I found a way to do it using existing callbacks. The idea is to create a base class for the test case with a flag telling the test case status and update this flag in the onFailure callback. Then during the run of the test I can add messages or callbacks to a collection and display/call them in the addTeardown callback.

classdef TestCaseBase < matlab.unittest.TestCase
    properties
        Failed = false
        MethodFailFns = {} 
    end
    
    methods
        function setFailed(testCase)
            testCase.Failed = true;
        end
        
        function runMethodFailFns(testCase)
            if testCase.Failed                
                for i = 1:numel(testCase.MethodFailFns)
                    fn = testCase.MethodFailFns{i};
                    fn();
                end
            end
        end
        
        function addOnMethodFail(testCase, fn)
            testCase.MethodFailFns{end + 1} = fn;
        end
    end   
    
    methods(TestMethodSetup)
        function setup(testCase)
            testCase.onFailure(@()setFailed(testCase));
            testCase.addTeardown(@runMethodFailFns, testCase);
        end
    end
end