 // case 1: first truncate to 1.5 blocks
    // we truncate 1 blocks, but not on the boundary, thus the diff should
    // be -block + (block - 0.5 block) = -0.5 block
 // case 1: first truncate to 1.5 blocks
    // we truncate 1 blocks, but not on the boundary, thus the diff should
    // be -block + (block - 0.5 block) = -0.5 block | TestTruncateQuotaUpdate.java