public void Node_should_return_appropriate_node_associated_with_partition()
{
IEnumerable <string> nodes = new CharRange('A', 'C').ToStrings();
var ch = new PartitionedConsistentHash(nodes, 32);
string node = ch.Node("foo");
node.Should().Be("B");
}
public void Hash_should_be_correct_value_when_high_order_bit_is_one()
{
var ch = new PartitionedConsistentHash(new[] { "a" });
var result = ch.Hash("this is a test");
result.Should().BeGreaterThan(0);
// Note: the 0 prefix is added by BigInteger to indicate it's a positive value
result.ToString("x").Should().Be("0fa26be19de6bff93f70bc2308434e4a440bbad02");
result.Should().Be(BigInteger.Parse("1428111681160539626773549155626795980060565941506"));
}
public void PreferenceList()
{
IEnumerable <string> nodes = new CharRange('A', 'J').ToStrings();
var ch = new PartitionedConsistentHash(nodes, 32);
string node = ch.Node("foo");
node.Should().Be("B");
var preferenceList = ch.PreferenceList("foo", 3); // belongs to node A
preferenceList.Should().BeEquivalentTo(new[] { "B", "C", "D" });
}
public void Hash_should_generate_correct_value()
{
// Generated SHA1 hash (for comparison) using npm 'sha1' or http://www.sha1-online.com/
// Generating a SHA1 in .NET is trivial, but this gives us a byte[]. We convert this
// to a BigInteger to make it easier to work and perform comparisons. BigInteger treats
// the byte array as little-endian which gives different results than you'll get from
// other SHA1 hash functions...
var ch = new PartitionedConsistentHash(new[] { "a" });
var result = ch.Hash("foo");
result.ToString("x").Should().Be("0beec7b5ea3f0fdbc95d0dd47f3c5bc275da8a33");
result.Should().Be(BigInteger.Parse("68123873083688143418383284816464454849230703155"));
// The Yubico ModHex converter (demo website) has some convenient hex-to-number conversions
// which is helpful to ensure BigInteger is providing the values we're expecting.
}
