sketch.nim

  test "Should actively cancel want-haves if block received from elsewhere":
    let
      # Peer wanting to download blocks
      downloader = nodes[4]
      # Bystander peer - gets block request but can't satisfy them
      bystander = nodes[3]
      # Holder of actual blocks
      blockHolder = nodes[1]

    await connectNodes(@[downloader, bystander])

    let downloaderId = downloader.switch.peerInfo.peerId
    let aBlock = blocks[0]
    let blockRequest = downloader.engine.requestBlock(aBlock.cid)

    # Bystander knows that downloader wants the block.
    check eventually(
      bystander
        .engine
        .peers
        .get(downloaderId)
        .peerWants
        .filterIt( it.address == aBlock.address )
        .len == 1
    )

    (await blockHolder.engine.localStore.putBlock(aBlock)).tryGet()
    await connectNodes(@[downloader, blockHolder])
    check (await blockRequest).cid == aBlock.cid

    # Downloader should have the block
    check (await downloader.engine.localStore.hasBlock(aBlock.cid)).tryGet()

    # Downloader should have actively cancelled the want-have at the bystander
    check eventually(
      bystander
        .engine
        .peers
        .get(downloaderId)
        .peerWants
        .filterIt( it.address == aBlock.address )
        .len == 0
    )