import matlab.unittest.constraints.IsEqualTo

% Create a TestCase for interactive use
testCase = matlab.unittest.TestCase.forInteractiveUse;

% Create StringDiagnostic upon failure
testCase.verifyThat(1, IsEqualTo(2), 'User supplied Diagnostic')

% Create FunctionHandleDiagnostic upon failure
testCase.verifyThat(1, IsEqualTo(2), @() system('ps'))

% Usage of user defined Diagnostic upon failure (see definition below)
testCase.verifyThat(1, IsEqualTo(2), ProcessStatusDiagnostic...
    ('Could not close my third party application!'))

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Diagnostic definition
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
classdef ProcessStatusDiagnostic < matlab.unittest.diagnostics.Diagnostic
    % ProcessStatusDiagnostic - an example diagnostic
    %
    %   Simple example to demonstrate how to create a custom
    %   diagnostic.
    
    properties
        
        % HeaderText - user-supplied header to display
        HeaderText = '(No header supplied)';
    end
    
    methods
        function diag = ProcessStatusDiagnostic(header)
            % Constructor - construct a ProcessStatusDiagnostic
            %
            %   The ProcessStatusDiagnostic constructor takes an
            %   optional header to be displayed along with process
            %   information.
            if (nargin >0)
                diag.HeaderText = header;
            end
        end
        
        function diagnose(diag)
            
            [status, processInfo] = system('ps');
            if (status ~= 0)
                processInfo = sprintf(...
                    ['!!! Could not obtain status diagnostic information!!!'...
                    ' [exit status code: %d]\n%s'], status, processInfo);
            end
            diag.DiagnosticText = sprintf('%s\n%s', diag.HeaderText,...
                processInfo);
        end
    end
    
end % classdef