public void AssignBlocksToPeersWithNodesWithDifferentChainsCorrectlyDistributesDownloadTasks()
{
int ourBlockCount = 5;
// Create list of numbers ourBlockCount + 1 to 40 and shuffle it.
Random rnd = new Random();
List <int> requiredBlockHeights = new List <int>();
for (int i = ourBlockCount + 1; i <= 40; i++)
{
requiredBlockHeights.Add(i);
}
requiredBlockHeights = requiredBlockHeights.OrderBy(a => rnd.Next()).ToList();
// Initialize node's peers.
List <PullerDownloadAssignments.PeerInformation> availablePeersInformation = new List <PullerDownloadAssignments.PeerInformation>()
{
new PullerDownloadAssignments.PeerInformation()
{
PeerId = "A",
QualityScore = 100,
ChainHeight = 4,
TasksAssignedCount = 0
},
new PullerDownloadAssignments.PeerInformation()
{
PeerId = "B",
QualityScore = 100,
ChainHeight = 20,
TasksAssignedCount = 0
},
new PullerDownloadAssignments.PeerInformation()
{
PeerId = "C",
QualityScore = 50,
ChainHeight = 30,
TasksAssignedCount = 0
},
new PullerDownloadAssignments.PeerInformation()
{
PeerId = "D",
QualityScore = 150,
ChainHeight = 40,
TasksAssignedCount = 0
},
};
// Use the assignment strategy to assign tasks to peers.
Dictionary <PullerDownloadAssignments.PeerInformation, List <int> > assignments = PullerDownloadAssignments.AssignBlocksToPeers(requiredBlockHeights, availablePeersInformation);
// Check the assignment is valid per our requirements.
int tasksAssigned = 0;
Assert.Equal(availablePeersInformation.Count, assignments.Count);
foreach (KeyValuePair <PullerDownloadAssignments.PeerInformation, List <int> > kvp in assignments)
{
PullerDownloadAssignments.PeerInformation peer = kvp.Key;
List <int> assignedBlockHeights = kvp.Value;
tasksAssigned += assignedBlockHeights.Count;
switch ((string)peer.PeerId)
{
case "A":
// Peer A should not get any work.
Assert.Equal(0, assignedBlockHeights.Count);
break;
case "B":
case "C":
case "D":
// Peers B and C should only get tasks to download blocks up to its chain height.
// Peer D can be assigned anything.
Assert.True((assignedBlockHeights.Count == 0) || (assignedBlockHeights.Max() <= peer.ChainHeight));
break;
default:
// This should never occur.
Assert.True(false, "Invalid peer ID.");
break;
}
}
Assert.Equal(requiredBlockHeights.Count, tasksAssigned);
}
public void AssignBlocksToPeersWithNodesWithLowQualityProtectsLowerHalfRequestsFromBeingAssignedToPoorQualityNodes()
{
Random rnd = new Random();
int ourBlockCount = rnd.Next(1000) + 1;
int bestBlockCount = rnd.Next(1000) + ourBlockCount + 1;
// Create list of numbers ourBlockCount + 1 to bestBlockCount and shuffle it.
List <int> requiredBlockHeights = new List <int>();
for (int i = ourBlockCount + 1; i <= bestBlockCount; i++)
{
requiredBlockHeights.Add(i);
}
requiredBlockHeights = requiredBlockHeights.OrderBy(a => rnd.Next()).ToList();
int medianBlockHeight = requiredBlockHeights.Median();
// Initialize node's peers. We have 5 peers with median quality 100.
// Thus peers A and E should not receive any work from the lower half of the requests.
List <PullerDownloadAssignments.PeerInformation> availablePeersInformation = new List <PullerDownloadAssignments.PeerInformation>()
{
new PullerDownloadAssignments.PeerInformation()
{
PeerId = "A",
QualityScore = 20,
ChainHeight = bestBlockCount,
TasksAssignedCount = rnd.Next(1000)
},
new PullerDownloadAssignments.PeerInformation()
{
PeerId = "B",
QualityScore = 100,
ChainHeight = bestBlockCount,
TasksAssignedCount = rnd.Next(1000)
},
new PullerDownloadAssignments.PeerInformation()
{
PeerId = "C",
QualityScore = 150,
ChainHeight = bestBlockCount,
TasksAssignedCount = rnd.Next(1000)
},
new PullerDownloadAssignments.PeerInformation()
{
PeerId = "D",
QualityScore = 120,
ChainHeight = bestBlockCount,
TasksAssignedCount = rnd.Next(1000)
},
new PullerDownloadAssignments.PeerInformation()
{
PeerId = "E",
QualityScore = 90,
ChainHeight = bestBlockCount,
TasksAssignedCount = rnd.Next(1000)
},
};
// Use the assignment strategy to assign tasks to peers.
Dictionary <PullerDownloadAssignments.PeerInformation, List <int> > assignments = PullerDownloadAssignments.AssignBlocksToPeers(requiredBlockHeights, availablePeersInformation);
// Check the assignment is valid per our requirements.
int tasksAssigned = 0;
Assert.Equal(availablePeersInformation.Count, assignments.Count);
foreach (KeyValuePair <PullerDownloadAssignments.PeerInformation, List <int> > kvp in assignments)
{
PullerDownloadAssignments.PeerInformation peer = kvp.Key;
List <int> assignedBlockHeights = kvp.Value;
tasksAssigned += assignedBlockHeights.Count;
switch ((string)peer.PeerId)
{
case "A":
case "E":
// Peers A and E should not get work.
Assert.True((assignedBlockHeights.Count == 0) || (assignedBlockHeights.Max() >= medianBlockHeight));
break;
case "B":
case "C":
case "D":
// PeerS B, C, D can be assigned anything.
break;
default:
// This should never occur.
Assert.True(false, "Invalid peer ID.");
break;
}
}
Assert.Equal(requiredBlockHeights.Count, tasksAssigned);
}
public void AssignBlocksToPeersWithManyNodesWithLowQualityProtectsLowerHalfRequestsFromBeingAssignedToPoorQualityNodes()
{
Random rnd = new Random();
int ourBlockCount = rnd.Next(1000) + 1;
int bestBlockCount = rnd.Next(1000) + ourBlockCount + 1;
// Create list of numbers ourBlockCount + 1 to bestBlockCount and shuffle it.
List <int> requiredBlockHeights = new List <int>();
for (int i = ourBlockCount + 1; i <= bestBlockCount; i++)
{
requiredBlockHeights.Add(i);
}
requiredBlockHeights = requiredBlockHeights.OrderBy(a => rnd.Next()).ToList();
int medianBlockHeight = requiredBlockHeights.Median();
// Randomly generate peers and count median quality.
List <PullerDownloadAssignments.PeerInformation> availablePeersInformation = new List <PullerDownloadAssignments.PeerInformation>();
int peerCount = rnd.Next(1000) + 1;
List <double> qualities = new List <double>();
for (int i = 0; i < peerCount; i++)
{
var peerInfo = new PullerDownloadAssignments.PeerInformation()
{
PeerId = i.ToString(),
QualityScore = rnd.NextDouble() * (QualityScore.MaxScore - QualityScore.MinScore) + QualityScore.MinScore,
ChainHeight = bestBlockCount,
TasksAssignedCount = rnd.Next(1000)
};
qualities.Add(peerInfo.QualityScore);
availablePeersInformation.Add(peerInfo);
}
;
double qualityMedian = qualities.Median();
// Use the assignment strategy to assign tasks to peers.
Dictionary <PullerDownloadAssignments.PeerInformation, List <int> > assignments = PullerDownloadAssignments.AssignBlocksToPeers(requiredBlockHeights, availablePeersInformation);
// Check the assignment is valid per our requirements.
int tasksAssigned = 0;
Assert.Equal(availablePeersInformation.Count, assignments.Count);
foreach (KeyValuePair <PullerDownloadAssignments.PeerInformation, List <int> > kvp in assignments)
{
PullerDownloadAssignments.PeerInformation peer = kvp.Key;
List <int> assignedBlockHeights = kvp.Value;
tasksAssigned += assignedBlockHeights.Count;
// If the peer is poor, it must not get bottom half work assignment.
if (peer.QualityScore < qualityMedian)
{
Assert.True((assignedBlockHeights.Count == 0) || (assignedBlockHeights.Max() >= medianBlockHeight));
}
}
Assert.Equal(requiredBlockHeights.Count, tasksAssigned);
}
public void AssignBlocksToPeersLargeSampleCorrectlyDistributesDownloadTasks()
{
Random rnd = new Random();
int iterationCount = 1000;
for (int iteration = 0; iteration < iterationCount; iteration++)
{
// Choose scenario for this iteration.
int ourBlockCount = rnd.Next(1000);
int bestChainBlockCount = ourBlockCount + rnd.Next(1000);
int availablePeerCount = rnd.Next(100) + 1;
List <int> requiredBlockHeights = new List <int>();
for (int i = ourBlockCount + 1; i <= bestChainBlockCount; i++)
{
requiredBlockHeights.Add(i);
}
requiredBlockHeights = requiredBlockHeights.OrderBy(a => rnd.Next()).ToList();
// Initialize node's peers.
int maxPeerChainLength = 0;
List <PullerDownloadAssignments.PeerInformation> availablePeersInformation = new List <PullerDownloadAssignments.PeerInformation>();
for (int peerIndex = 0; peerIndex < availablePeerCount; peerIndex++)
{
PullerDownloadAssignments.PeerInformation peerInfo = new PullerDownloadAssignments.PeerInformation()
{
ChainHeight = rnd.Next(bestChainBlockCount) + 1,
PeerId = peerIndex,
QualityScore = rnd.NextDouble() * (QualityScore.MaxScore - QualityScore.MinScore) + QualityScore.MinScore,
TasksAssignedCount = rnd.Next(100)
};
availablePeersInformation.Add(peerInfo);
maxPeerChainLength = Math.Max(maxPeerChainLength, peerInfo.ChainHeight);
}
// Use the assignment strategy to assign tasks to peers.
Dictionary <PullerDownloadAssignments.PeerInformation, List <int> > assignments = PullerDownloadAssignments.AssignBlocksToPeers(requiredBlockHeights, availablePeersInformation);
// Check the assignment is valid per our requirements.
int tasksAssigned = 0;
Assert.Equal(availablePeersInformation.Count, assignments.Count);
foreach (KeyValuePair <PullerDownloadAssignments.PeerInformation, List <int> > kvp in assignments)
{
PullerDownloadAssignments.PeerInformation peer = kvp.Key;
List <int> assignedBlockHeights = kvp.Value;
tasksAssigned += assignedBlockHeights.Count;
// Peers with shorter chain should not get any work
// other peers should not get any work exceeding their knowledge.
if (peer.ChainHeight <= ourBlockCount)
{
Assert.Equal(0, assignedBlockHeights.Count);
}
else if (assignedBlockHeights.Count > 0)
{
Assert.True(assignedBlockHeights.Max() <= peer.ChainHeight);
}
}
// Check that all tasks that could be assigned were assigned.
int taskShouldAssign = requiredBlockHeights.Where(r => r <= maxPeerChainLength).Count();
Assert.Equal(taskShouldAssign, tasksAssigned);
}
}
