def test_find_node_after_removal(self):
nodes = ['0', '1', '2']
rendezvous = RendezvousHash(nodes=nodes)
rendezvous.remove_node('1')
self.assertEqual('0', rendezvous.find_node('ok'))
self.assertEqual('0', rendezvous.find_node('mykey'))
self.assertEqual('2', rendezvous.find_node('wat'))
def test_shrink(self):
rendezvous = RendezvousHash()
placements = {}
for i in range(10):
rendezvous.add_node(str(i))
placements[str(i)] = []
for i in range(1000):
node = rendezvous.find_node(str(i))
placements[node].append(i)
rendezvous.remove_node('9')
new_placements = {}
for i in range(9):
new_placements[str(i)] = []
for i in range(1000):
node = rendezvous.find_node(str(i))
new_placements[node].append(i)
keys = [k for sublist in placements.values() for k in sublist]
new_keys = [k for sublist in new_placements.values() for k in sublist]
self.assertEqual(sorted(keys), sorted(new_keys))
added = 0
removed = 0
for node, assignments in placements.items():
after = set(assignments)
before = set(new_placements.get(node, []))
removed += len(before.difference(after))
added += len(after.difference(before))
self.assertEqual(added, removed)
self.assertEqual(202, (added + removed))
def test_find_node_after_removal(self):
nodes = ['0', '1', '2']
rendezvous = RendezvousHash(nodes=nodes)
rendezvous.remove_node('1')
self.assertEqual('0', rendezvous.find_node('ok'))
self.assertEqual('0', rendezvous.find_node('mykey'))
self.assertEqual('2', rendezvous.find_node('wat'))
def test_shrink(self):
rendezvous = RendezvousHash()
placements = {}
for i in range(10):
rendezvous.add_node(str(i))
placements[str(i)] = []
for i in range(1000):
node = rendezvous.find_node(str(i))
placements[node].append(i)
rendezvous.remove_node('9')
new_placements = {}
for i in range(9):
new_placements[str(i)] = []
for i in range(1000):
node = rendezvous.find_node(str(i))
new_placements[node].append(i)
keys = [k for sublist in placements.values() for k in sublist]
new_keys = [k for sublist in new_placements.values() for k in sublist]
self.assertEqual(sorted(keys), sorted(new_keys))
added = 0
removed = 0
for node, assignments in placements.items():
after = set(assignments)
before = set(new_placements.get(node, []))
removed += len(before.difference(after))
added += len(after.difference(before))
self.assertEqual(added, removed)
self.assertEqual(202, (added + removed))
def test_remove_node(self):
nodes = ['0', '1', '2']
rendezvous = RendezvousHash(nodes=nodes)
rendezvous.remove_node('2')
self.assertEqual(2, len(rendezvous.nodes))
self.assertRaises(ValueError, rendezvous.remove_node, '2')
self.assertEqual(2, len(rendezvous.nodes))
rendezvous.remove_node('1')
self.assertEqual(1, len(rendezvous.nodes))
rendezvous.remove_node('0')
self.assertEqual(0, len(rendezvous.nodes))
def test_remove_node(self):
nodes = ['0', '1', '2']
rendezvous = RendezvousHash(nodes=nodes)
rendezvous.remove_node('2')
self.assertEqual(2, len(rendezvous.nodes))
self.assertRaises(ValueError, rendezvous.remove_node, '2')
self.assertEqual(2, len(rendezvous.nodes))
rendezvous.remove_node('1')
self.assertEqual(1, len(rendezvous.nodes))
rendezvous.remove_node('0')
self.assertEqual(0, len(rendezvous.nodes))