       // |c1| |    c2    | |c3|
          assert.isTrue(positionEquals(c1, 0, 50, 0, 50), "child 1 position ok");
          assert.isTrue(positionEquals(c2, 0, 50, 50, 250), "child 2 position ok");
          assert.isTrue(positionEquals(c3, 0, 50, 250, 300), "child 3 position ok");
        });

        test('layout-flex child in a vertical layout', function() {
          container.classList.add('vertical');
          container.classList.add('tall');
          c2.classList.add('flex');
          assert.isTr