private void verifyNumber(int n, byte [] expected) {
        ByteBuffer buf = ByteBuffer.allocate(expected.length);
        IntegerCompressor.putCompressedNumber(n, buf);
        assertArrayEquals(expected, buf.array());
    }
Test that integers compresses correctly.

@author baldersheim
vespajlib/src/test/java/com/yahoo/compress/IntegerCompressorTest.java