Can't use import in meteor testing

I do not understand this error. Why can't I use import?

import { chai } from 'meteor/practicalmeteor:chai';
^^^^^^
SyntaxError: Unexpected reserved word

package.js

Package.onTest(function(api) {
    api.use('practicalmeteor:mocha');

    api.addFiles('tests/test.js');
});

test.js

import { chai } from 'meteor/practicalmeteor:chai';

describe('Array', function() {
    describe('#indexOf()', function () {
        it('should return -1 when the value is not present', function () {
            chai.assert.equal(-1, [1,2,3].indexOf(5));
            chai.assert.equal(-1, [1,2,3].indexOf(0));
        });
    });
});