How can I test a long function in Matlab?

Hello community,

I have to test certain functions and some of them are very long, how can I generate a test that verifies it?

Thank you so much,

Gabriela

Answer 1

[Jan]

You test them the same way as you test short functions:

• Provide a set with specific input data and compare the results with known outputs
• Check if the output is very sensitive to a tiny variation of the inputs. If so, the function is an expensive random number generator.
• Call the function with irregulare values and check, if it throws error messages
• Check for NaN, +/-Inf, empty input, wrong file names, cell arrays instead of matrices etc.

Because it might be really hard to obtain some valid output data without using the original function, a validation of code usually requires to split the code to smaller functions, which can be tested independently. If the code is e.g. an integrator, you could compare the results with other integrators.

The base of unit-testing is to split the functions into units, whose output can be checked with controllable methods.

[Gabriela Garaizabal Etxeberria]

Thank you so much!!

[Gabriela Garaizabal Etxeberria]

And, another doubt:

I have a function that collects some parameters of an interface and whose result is in an Excel. How can I test that Excel is generated correctly?

Hear is the code that I have started:

classdef Test1 < matlab.unittest.TestCase
    
    properties
    end
    
    methods (Test)
        function graphicsTest(testCase)
            actSolution=graphics(2,0,700,320);
%             expSolution=?
%             testCase.verifyEqual(?)
            
        end
    end
end

[Jan]

I'm not sure, what you want to test here.

Answer 2

[John D'Errico]

Don't test your long function. Because you should be writing SHORT functions. Then you can test each piece, verify it works as designed. And only then put it all together.