def test_merge_servers(self):
# merge_servers merges a list of upload_servers and a dict of
# shareid -> serverid mappings.
shares = {
1: set(["server1"]),
2: set(["server2"]),
3: set(["server3"]),
4: set(["server4", "server5"]),
5: set(["server1", "server2"]),
}
# if not provided with a upload_servers argument, it should just
# return the first argument unchanged.
self.failUnlessEqual(shares, merge_servers(shares, set([])))
trackers = []
for (i, server) in [(i, "server%d" % i) for i in range(5, 9)]:
t = FakeServerTracker(server, [i])
trackers.append(t)
expected = {
1: set(["server1"]),
2: set(["server2"]),
3: set(["server3"]),
4: set(["server4", "server5"]),
5: set(["server1", "server2", "server5"]),
6: set(["server6"]),
7: set(["server7"]),
8: set(["server8"]),
}
self.failUnlessEqual(expected, merge_servers(shares, set(trackers)))
shares2 = {}
expected = {
5: set(["server5"]),
6: set(["server6"]),
7: set(["server7"]),
8: set(["server8"]),
}
self.failUnlessEqual(expected, merge_servers(shares2, set(trackers)))
shares3 = {}
trackers = []
expected = {}
for (i, server) in [(i, "server%d" % i) for i in range(10)]:
shares3[i] = set([server])
t = FakeServerTracker(server, [i])
trackers.append(t)
expected[i] = set([server])
self.failUnlessEqual(expected, merge_servers(shares3, set(trackers)))
def test_servers_of_happiness_utility_function(self):
# These tests are concerned with the servers_of_happiness()
# utility function, and its underlying matching algorithm. Other
# aspects of the servers_of_happiness behavior are tested
# elsehwere These tests exist to ensure that
# servers_of_happiness doesn't under or overcount the happiness
# value for given inputs.
# servers_of_happiness expects a dict of
# shnum => set(serverids) as a preexisting shares argument.
test1 = {
1: set(["server1"]),
2: set(["server2"]),
3: set(["server3"]),
4: set(["server4"])
}
happy = servers_of_happiness(test1)
self.failUnlessEqual(4, happy)
test1[4] = set(["server1"])
# We've added a duplicate server, so now servers_of_happiness
# should be 3 instead of 4.
happy = servers_of_happiness(test1)
self.failUnlessEqual(3, happy)
# The second argument of merge_servers should be a set of objects with
# serverid and buckets as attributes. In actual use, these will be
# ServerTracker instances, but for testing it is fine to make a
# FakeServerTracker whose job is to hold those instance variables to
# test that part.
trackers = []
for (i, server) in [(i, "server%d" % i) for i in range(5, 9)]:
t = FakeServerTracker(server, [i])
trackers.append(t)
# Recall that test1 is a server layout with servers_of_happiness
# = 3. Since there isn't any overlap between the shnum ->
# set([serverid]) correspondences in test1 and those in trackers,
# the result here should be 7.
test2 = merge_servers(test1, set(trackers))
happy = servers_of_happiness(test2)
self.failUnlessEqual(7, happy)
# Now add an overlapping server to trackers. This is redundant,
# so it should not cause the previously reported happiness value
# to change.
t = FakeServerTracker("server1", [1])
trackers.append(t)
test2 = merge_servers(test1, set(trackers))
happy = servers_of_happiness(test2)
self.failUnlessEqual(7, happy)
test = {}
happy = servers_of_happiness(test)
self.failUnlessEqual(0, happy)
# Test a more substantial overlap between the trackers and the
# existing assignments.
test = {
1: set(['server1']),
2: set(['server2']),
3: set(['server3']),
4: set(['server4']),
}
trackers = []
t = FakeServerTracker('server5', [4])
trackers.append(t)
t = FakeServerTracker('server6', [3, 5])
trackers.append(t)
# The value returned by servers_of_happiness is the size
# of a maximum matching in the bipartite graph that
# servers_of_happiness() makes between serverids and share
# numbers. It should find something like this:
# (server 1, share 1)
# (server 2, share 2)
# (server 3, share 3)
# (server 5, share 4)
# (server 6, share 5)
#
# and, since there are 5 edges in this matching, it should
# return 5.
test2 = merge_servers(test, set(trackers))
happy = servers_of_happiness(test2)
self.failUnlessEqual(5, happy)
# Zooko's first puzzle:
# (from http://allmydata.org/trac/tahoe-lafs/ticket/778#comment:156)
#
# server 1: shares 0, 1
# server 2: shares 1, 2
# server 3: share 2
#
# This should yield happiness of 3.
test = {
0: set(['server1']),
1: set(['server1', 'server2']),
2: set(['server2', 'server3']),
}
self.failUnlessEqual(3, servers_of_happiness(test))
# Zooko's second puzzle:
# (from http://allmydata.org/trac/tahoe-lafs/ticket/778#comment:158)
#
# server 1: shares 0, 1
# server 2: share 1
#
# This should yield happiness of 2.
test = {
0: set(['server1']),
1: set(['server1', 'server2']),
}
self.failUnlessEqual(2, servers_of_happiness(test))