ter-50, center, 50, 100), "child 2 position ok");
          assert.isTrue(positionEquals(c3, center, center+50, 0, 50), "child 3 position ok");
          assert.isTrue(positionEquals(c4, center, center+50, 50, 100), "child 4 position ok");
          assert.isTrue(positionEquals(c5, center+50, center+100, 0, 50), "child 5 position ok");
        });

        test('layout-between-aligned', function() {
          container.classList.add('between-aligned');
          assert.isTrue(positionEquals(container, 0, 30