public long floorFrameTs(long timestamp) {
        return subtractClamped(timestamp, floorMod(
                (timestamp >= Long.MIN_VALUE + frameOffset ? timestamp : timestamp + frameSize) - frameOffset,
                frameSize
        ));
    }
@Test
    public void when_frameLength3() {
        definition = new SlidingWindowPolicy(3, 0, 10);
        assertEquals(Long.MIN_VALUE, definition.floorFrameTs(Long.MIN_VALUE));
    }