public void UpdateInvokeCountWhenInputValid()
    {
        TestableMemberControlPanel control = new TestableMemberControlPanel();

        control.invoke_box.Text = uint.MaxValue.ToString();
        control.invoke_box_Validating(null, null);
        Assert.AreEqual(uint.MaxValue, control.InvokeCount);
    }
    public void ValidationErrorWhenInvokeCountNegative()
    {
        TestableMemberControlPanel control = new TestableMemberControlPanel();

        control.InvokeCount     = 888;
        control.invoke_box.Text = "-1";
        control.invoke_box_Validating(null, null);
        Assert.AreEqual("Enter a valid whole number greater than 0.", control.validation_error_message);
        Assert.AreEqual(888, control.InvokeCount);
    }