test.js

class FormFixture extends Fixture {
   @element submitButton;
  
   submit() {
     this.submitButton.click(); 
   }
}

class FooFixture extends FormFixture {
    constructor() {
        super('data-test-root');
    }

    @element emailField;
    @element commitButton;
    @element label;


    async enterEmail(email) {
        await this.emailField.fillIn(email);
        return this.commitButton.click();
    }
}

const fixture = new FooFixture();

describe("foo form', function() {
    
   // embjs front matter
         
  it('renders', function() {
    fixture.should.be.rendered
  });
   
  it('submits the form', function() {
    fixture.enterEmail('[email protected]');
    fxiture.submit();
    label.should.haveText('Success');
  });
});