<aura:component description="TestSelectW18">
        <aura:handler name="init" value="{!this}" action="{!c.doInit}"/>
        <aura:attribute name="dynamicComp" type="Aura.Component"/>
            {!v.dynamicComp}
    </aura:component>

({
        doInit: function (component, event, helper) {
            $A.createComponent(
                'ui:inputSelect',
                {
                    'aura:id': 'findableAuraId',
                    label: 'Test',
                    required: false,
                    change: {},
                    options: [
                        {
                            class: 'optionClass',
                            label: 'test1',
                            value: 'test1',
                            selected: 'true'
                        },
                        {
                            class: 'optionClass',
                            label: 'test2',
                            value: 'test2'
                        }
                    ],
                    multiple: 'false',
                    size: 1
                },
                function (newComp, status, errorMessage) {
                    if (status === 'SUCCESS' && component.isValid()) {
                        component.set('v.dynamicComp', newComp);
                    } else if (status === 'INCOMPLETE') {
                        console.log('No response from server.');
                    } else if (status === 'ERROR') {
                        console.log('Error: ' + errorMessage);
                    }
                }
            );
        }
    })