text: import { List } from 'immutable';
  import { expect } from 'chai';
  import dbnUtils from '../../public/js/utils/dbn_utils';
  
  describe('dbnUtils', function() {
    describe('#createStructure', function() {
      let sequence;
      let dbn;
  
      describe('when given invalid params', function() {
        beforeEach(function() {
          sequence = 'zxcv';
          dbn = '.((';
        });
  
        it('should throw an error', function () {
          const createStructureBound = dbnUtils.createStructure.bind(dbnUtils, sequence, dbn);
          expect(createStructureBound).to.throw(Error);
        });
      });
  
      describe('when given valid params', function() {
        beforeEach(function() {
          sequence = 'CATG';
          dbn = '.().';
        });
  
        it('should return an Immutable.List of same length', function() {
          const response = dbnUtils.createStructure(sequence, dbn);
  
  
          expect(response).to.be.an.instanceof(List);
          expect(response.size).to.equal(sequence.length);
        });
      });
    });
  });
  