text: import { d3Attr } from 'dummy/helpers/d3-attr';
  import { test } from 'qunit';
  import d3UnitModule from '../../helpers/d3-unit-helper';
  
  d3UnitModule('Unit | Helper | d3 attr');
  
  test('it returns a function', function(assert) {
    assert.equal(typeof d3Attr(['r', 10]), 'function');
  });
  
  
  test('attribute helper', function(assert) {
    let { d3Selection } = this;
    
    assert.ok(d3Selection.attr, 'has attr method');
    
    assert.equal(d3Selection.attr('opacity'), null, 'does not have attribute before setting');
  
    d3Attr(['opacity', '1.0'])(d3Selection);
    assert.equal(d3Selection.attr('opacity'), 1.0, 'attribute can be set');
  
    d3Attr(['opacity', '0.2'])(d3Selection);
    assert.equal(d3Selection.attr('opacity'), 0.2, 'attribute can be changed');
  });
  