Matlab: test a class that takes user keyboard input

I would like to test a class GetInput that gets keyboard input from the user. How can my test class provide simulated keyboard input to GetInput? Here's the class to be tested.

classdef GetInput

    properties
        Answer
    end

    methods
        function obj = GetInput
            obj.Answer = input("Your answer? ","s");
        end
    end
end

And here's the test class.

classdef testGetInput < matlab.unittest.TestCase

    methods (Test)

        function tInput(testCase)
            g = GetInput();    
            myInput = 'abcdef';
            % I want to provide input automatically at this point   
            verifyEqual(testCase,g.Answer,myInput)
        end
    end
end

This all works, but only if I manually type in "abcdef" at the command window prompt. I want a way to automate the keyboard input.

Here's how you can do it. It's a bit roundabout. Start with an input interface class:

classdef (Abstract) InputInterface
    methods
        inp = getInput(inputGetter,prompt)
    end
end

Create a default input class KeyboardInput that inherits from the abstract interface:

classdef KeyboardInput < InputInterface
    methods
        function inp = getInput(~,prompt) % 1st input arg is InputInterface obj
            inp = input(prompt,"s");
        end
    end
end

Add a class UserQuery that uses one of these input classes:

classdef UserQuery < handle

    properties
        InputSource
        Response
    end

    methods
        function obj = UserQuery(inputSrc)
            arguments
                inputSrc (1,1) InputInterface = KeyboardInput
            end
            obj.InputSource = inputSrc;
        end

        function ask(obj,prompt)
            obj.Response = obj.InputSource.getInput(prompt);
        end
    end
end

Now test UserQuery with a mock:

classdef tUserQuery < matlab.mock.TestCase

    properties
        Mock
        Behavior
        Asker
    end

    methods (Test)
        function testInput(tc)
            userSaid = "whatUserSaid";
            when(tc.Behavior.getInput(99), ...
                matlab.mock.actions.AssignOutputs(userSaid))
            tc.Asker.ask(99)            
            tc.verifyTrue(isequal(tc.Asker.Response,userSaid))
        end
    end

    methods (TestClassSetup)
        function setupMock(tc)
            [tc.Mock,tc.Behavior] = tc.createMock(?InputInterface);
            tc.Asker = UserQuery(tc.Mock);
        end
    end

end    

The mock inherits from the abstract InputInterface, so the UserQuery accepts it as an input argument. The mock behavior is set up so that when it's called with input argument 99, it outputs "whatUserSaid".

>> q = UserQuery(KeyboardInput);
>> q.ask("Your answer? ")
Your answer? yes
>> q

q = 

  UserQuery with properties:

    InputSource: [1×1 KeyboardInput]
       Response: 'yes'

>>