nim-eth/tests/p2p/test_routing_table.nim

import
  std/unittest,
  bearssl, eth/keys, eth/p2p/discoveryv5/[routing_table, node],
  ./discv5_test_helper

suite "Routing Table Tests":
  let rng = newRng()

  test "Bucket splitting in range branch b=1":
    let node = generateNode(PrivateKey.random(rng[]))
    var table: RoutingTable

    # bitsPerHop = 1 -> Split only the branch in range of own id
    table.init(node, 1, rng)

    for j in 0..5'u32:
      for i in 0..<BUCKET_SIZE:
        check table.addNode(node.nodeAtDistance(rng[], 256-j)) == nil
      check table.addNode(node.nodeAtDistance(rng[], 256-j)) != nil

  test "Bucket splitting off range branch b=1":
    let node = generateNode(PrivateKey.random(rng[]))
    var table: RoutingTable

    # bitsPerHop = 1 -> Split only the branch in range of own id
    table.init(node, 1, rng)

    # Add 16 nodes, distance 256
    for i in 0..<BUCKET_SIZE:
      check table.addNode(node.nodeAtDistance(rng[], 256)) == nil

    # This should split the bucket in the distance 256 branch, and the distance
    # <=255 branch. But not add the node, as distance 256 bucket is already full
    # and b=1 will not allow it to spit any further
    check table.addNode(node.nodeAtDistance(rng[], 256)) != nil

    # This add should be allowed as it is on the branch where the own node's id
    # id belongs to.
    check table.addNode(node.nodeAtDistance(rng[], 255)) == nil

  test "Bucket splitting off range branch b=2":
    let node = generateNode(PrivateKey.random(rng[]))
    var table: RoutingTable

    # bitsPerHop = 2, allow not in range branch to split once (2 buckets).
    table.init(node, 2, rng)

    # Add 16 nodes, distance 256 from `node`, but all with 2 bits shared prefix
    # among themselves.
    let firstNode = node.nodeAtDistance(rng[], 256)
    check table.addNode(firstNode) == nil
    for n in 1..<BUCKET_SIZE:
      check table.addNode(firstNode.nodeAtDistance(rng[], 254)) == nil

    # Add 16 more nodes with only 1 bit shared prefix with previous 16. This
    # should cause the initial bucket to split and and fill the second bucket
    # with the 16 new entries.
    for n in 0..<BUCKET_SIZE:
      check table.addNode(firstNode.nodeAtDistance(rng[], 255)) == nil

    # Adding another should fail as both buckets will be full and not be
    # allowed to split another time.
    check table.addNode(node.nodeAtDistance(rng[], 256)) != nil
    # And also when targetting one of the two specific buckets.
    check table.addNode(firstNode.nodeAtDistance(rng[], 255)) != nil
    check table.addNode(firstNode.nodeAtDistance(rng[], 254)) != nil
    # This add should be allowed as it is on the branch where the own node's id
    # id belongs to.
    check table.addNode(node.nodeAtDistance(rng[], 255)) == nil

  test "Replacement cache":
    let node = generateNode(PrivateKey.random(rng[]))
    var table: RoutingTable

    # bitsPerHop = 1 -> Split only the branch in range of own id
    table.init(node, 1, rng)

    # create a full bucket
    let bucketNodes = node.nodesAtDistance(rng[], 256, BUCKET_SIZE)
    for n in bucketNodes:
      check table.addNode(n) == nil

    # create a full replacement cache
    let replacementNodes = node.nodesAtDistance(rng[], 256, REPLACEMENT_CACHE_SIZE)
    for n in replacementNodes:
      check table.addNode(n) != nil

    # Add one more node to replacement (would drop first one)
    let lastNode = node.nodeAtDistance(rng[], 256)
    check table.addNode(lastNode) != nil

    # This should replace the last node in the bucket, with the last one of
    # the replacement cache.
    table.replaceNode(table.nodeToRevalidate())
    block:
      # Should return the last node of the replacement cache successfully.
      let result = table.getNode(lastNode.id)
      check:
        result.isSome()
        result.get() == lastNode
    block:
      # This node should be removed
      check (table.getNode(bucketNodes[bucketNodes.high].id)).isNone()

  test "Empty bucket":
    let node = generateNode(PrivateKey.random(rng[]))
    var table: RoutingTable

    # bitsPerHop = 1 -> Split only the branch in range of own id
    table.init(node, 1, rng)

    check table.nodeToRevalidate().isNil()

    # try to replace not existing node
    table.replaceNode(generateNode(PrivateKey.random(rng[])))
    check table.len == 0

    let addedNode = generateNode(PrivateKey.random(rng[]))
    check table.addNode(addedNode) == nil
    check table.len == 1

    # try to replace not existing node
    table.replaceNode(generateNode(PrivateKey.random(rng[])))
    check table.len == 1

    table.replaceNode(addedNode)
    check table.len == 0

  test "Empty replacement cache":
    let node = generateNode(PrivateKey.random(rng[]))
    var table: RoutingTable

    # bitsPerHop = 1 -> Split only the branch in range of own id
    table.init(node, 1, rng)

    # create a full bucket TODO: no need to store bucketNodes
    let bucketNodes = node.nodesAtDistance(rng[], 256, BUCKET_SIZE)
    for n in bucketNodes:
      check table.addNode(n) == nil

    table.replaceNode(table.nodeToRevalidate())
    # This node should still be removed
    check (table.getNode(bucketNodes[bucketNodes.high].id)).isNone()

  test "Double add":
    let node = generateNode(PrivateKey.random(rng[]))
    var table: RoutingTable

    # bitsPerHop = 1 -> Split only the branch in range of own id
    table.init(node, 1, rng)

    let doubleNode = node.nodeAtDistance(rng[], 256)
    # Try to add the node twice
    check table.addNode(doubleNode) == nil
    check table.addNode(doubleNode) == nil

    for n in 0..<BUCKET_SIZE-1:
      check table.addNode(node.nodeAtDistance(rng[], 256)) == nil

    check table.addNode(node.nodeAtDistance(rng[], 256)) != nil
    # Check when adding again once the bucket is full
    check table.addNode(doubleNode) == nil

    # Test if its order is preserved, there is one node in replacement cache
    # which is why we run `BUCKET_SIZE` times.
    for n in 0..<BUCKET_SIZE:
      table.replaceNode(table.nodeToRevalidate())

    let result = table.getNode(doubleNode.id)
    check:
      result.isSome()
      result.get() == doubleNode
      table.len == 1

  test "Double replacement add":
    let node = generateNode(PrivateKey.random(rng[]))
    var table: RoutingTable

    # bitsPerHop = 1 -> Split only the branch in range of own id
    table.init(node, 1, rng)

    # create a full bucket
    let bucketNodes = node.nodesAtDistance(rng[], 256, BUCKET_SIZE)
    for n in bucketNodes:
      check table.addNode(n) == nil

    # create a full replacement cache
    let replacementNodes = node.nodesAtDistance(rng[], 256, REPLACEMENT_CACHE_SIZE)
    for n in replacementNodes:
      check table.addNode(n) != nil

    check table.addNode(replacementNodes[0]) != nil

    table.replaceNode(table.nodeToRevalidate())
    block:
      # Should return the last node of the replacement cache successfully.
      let result = table.getNode(replacementNodes[0].id)
      check:
        result.isSome()
        result.get() == replacementNodes[0]
    block:
      # This node should be removed
      check (table.getNode(bucketNodes[bucketNodes.high].id)).isNone()

  test "Just seen":
    let node = generateNode(PrivateKey.random(rng[]))
    var table: RoutingTable

    # bitsPerHop = 1 -> Split only the branch in range of own id
    table.init(node, 1, rng)

    # create a full bucket
    let bucketNodes = node.nodesAtDistance(rng[], 256, BUCKET_SIZE)
    for n in bucketNodes:
      check table.addNode(n) == nil

    # swap seen order
    for n in bucketNodes:
      table.setJustSeen(n)

    for n in bucketNodes:
      table.replaceNode(table.nodeToRevalidate())
      check (table.getNode(n.id)).isNone()

  test "Just seen replacement":
    let node = generateNode(PrivateKey.random(rng[]))
    var table: RoutingTable

    # bitsPerHop = 1 -> Split only the branch in range of own id
    table.init(node, 1, rng)

    # create a full bucket
    let bucketNodes = node.nodesAtDistance(rng[], 256, BUCKET_SIZE)
    for n in bucketNodes:
      check table.addNode(n) == nil

    # create a full replacement cache
    let replacementNodes = node.nodesAtDistance(rng[], 256, REPLACEMENT_CACHE_SIZE)
    for n in replacementNodes:
      check table.addNode(n) != nil

    for i in countdown(replacementNodes.high, 0):
      table.replaceNode(table.nodeToRevalidate())
      table.setJustSeen(replacementNodes[i])

    for n in replacementNodes:
      let result = table.getNode(n.id)
      check:
        result.isSome()
        result.get() == n

    for i in 0..<int(BUCKET_SIZE/2):
      let result = table.getNode(bucketNodes[i].id)
      check:
        result.isSome()
        result.get() == bucketNodes[i]