function defineTest(name, data) {
      it(name, () => {
        const b = createFakeBuffered(
            [{start: 10, end: 20}, {start: 30, end: 40}, {start: 50, end: 60}]);
        expect(TimeRangesUtils.getGapIndex(
            b, data.time, 0.1)).toBe(data.expected);
      });
    }
@param {string} name
@param {{time: number, expected: ?number}} data