[cyber]

kobezzza, вот что получилось в итоге, теперь я понял почему нужно писать тесты

describe('new ModalJS', function()  {

    var modal;

    it( 'new Object', function()  {

        modal = new ModalJS();

        expect( typeof modal  )
            .toBe( "object" );
    });

    it ( "Create overlay", function () {

        expect ( isHTMLElement( modal.overlay) )
            .toBe( true );

        expect ( modal.overlay.parentElement )
            .toBe( document.body );


    } );

});

function isHTMLElement( elem ) {
    return (typeof elem === "object") &&
        (elem.nodeType === 1) && (typeof elem.style === "object") &&
        (typeof elem.ownerDocument ==="object");
}

describe ( "Methods", function () {

    var modal, win;

    function resetWindow ( ) {

            win = document.getElementById( "modal-test-win");
            win2 = document.getElementById( "modal-test-win2");
            modal = new ModalJS( {
                NotUseAnimate: true
            } ).setWindow ( win || win2 );
    }

    resetWindow();

    it( "set window", function ()  {

        expect( modal.setWindow ( win ))
            .toEqual ( modal );
    });


    it ( "Show window", function ( ) {

        expect ( modal.show () )
            .toBe ( true );
    } );

    it ( "Hide window", function ( ) {

        expect ( modal.hide () )
            .toBe ( true );
    } );


    it ( "Window destroy", function ( ) {

        expect ( modal.destroy( ) )
            .toBe ( true );

    } );


    it ( "Window destroy [remove Window]", function ( ) {

        resetWindow ( );

        expect ( modal.destroy( true ) )
            .toBe ( true );

        expect ( modal.window )
            .toBeUndefined();
    } );


} );


describe ( "Async animate", function ( ) {

    var win2 = document.getElementById( "modal-test-win2"),
        modal = new ModalJS().setWindow ( win2 );

    beforeEach( function ( done )  {

        modal.on ( "showed", done );
        modal.show();
    } );


    it ( "Hide window", function ( done ) {

        modal.on ( "closed", done );
        modal.hide();

    } );

});