def test_merge_update_key_collision():
crdt_1, crdt_2 = CRDT(), CRDT()
crdt_1.add('a', 1)
crdt_2.add('b', 2)
crdt_1.update('a', 'b')
merged = merge(crdt_1, crdt_2)
# In this implementation of LWW the update should overwrite the original key if the key already exists
assert merged.data == {'b': 1}
def test_merge_remove_same_key_twice():
crdt_1, crdt_2 = CRDT(), CRDT()
crdt_1.add('a', 1)
crdt_2.add('a', 1)
crdt_1.remove('a')
crdt_2.remove('a')
# In a merged set, since the key is removed before, the later remove should be ignored
merged = merge(crdt_1, crdt_2)
assert len(merged.data) == 0
def test_merge_update_same_key_twice():
crdt_1, crdt_2 = CRDT(), CRDT()
crdt_1.add('a', 1)
crdt_2.add('a', 2)
crdt_1.update('a', 'b')
crdt_2.update('a', 'c')
merged = merge(crdt_1, crdt_2)
# In a LWW merge, only the latest update should be present
assert merged.data == {'c': 2}
def test_merge_add_only(ans):
crdt_1, crdt_2 = CRDT(), CRDT()
ans_1, ans_2 = slice_dict(ans, 0, len(ans) // 2), slice_dict(ans, len(ans) // 2, len(ans))
for k, v in ans_1.items():
crdt_1.add(k, v)
for k, v in ans_2.items():
crdt_2.add(k, v)
merged = merge(crdt_1, crdt_2)
assert len(merged.log) == len(crdt_1.log) + len(crdt_2.log)
assert merged.data == ans
def test_add_one():
crdt = CRDT()
crdt.add('a', 1)
assert len(crdt.log) == 1
assert crdt.data == {'a': 1}
assert crdt.log[0].op == ADD
def test_merge_add_same_key_diff_values(ans):
crdt_1, crdt_2 = CRDT(), CRDT()
ans_alt = {k:v + 1 for k, v in ans.items()}
for k, v in ans.items():
crdt_1.add(k, v)
for k, v in ans_alt.items():
crdt_2.add(k, v)
merged = merge(crdt_1, crdt_2)
assert len(merged.log) == len(crdt_1.log) + len(crdt_2.log)
# Only the values updated later should be present
assert merged.data == ans_alt
def test_add_many(ans):
crdt = CRDT()
for k, v, in ans.items():
crdt.add(k, v)
assert len(crdt.log) == len(ans)
assert crdt.data == ans
def test_update_one():
crdt = CRDT()
crdt.add('a', 1)
crdt.update('a', 'b')
assert len(crdt.log) == 2
assert crdt.data == {'b': 1}
assert crdt.log[1].op == UPDATE
def test_remove_one():
crdt = CRDT()
crdt.add('a', 1)
crdt.remove('a')
assert len(crdt.log) == 2
assert len(crdt.data) == 0
assert crdt.log[1].op == REMOVE
def test_merge_add_remove(ans):
crdt_1, crdt_2 = CRDT(), CRDT()
ans_1, ans_2 = slice_dict(ans, 0, len(ans) // 2), slice_dict(ans, len(ans) // 2, len(ans))
# Both CRDTs contain the same data initially
for k, v in ans.items():
crdt_1.add(k, v)
crdt_2.add(k, v)
# Remove second half of the ans set in crdt_2
for k in ans_2:
crdt_2.remove(k)
merged = merge(crdt_1, crdt_2)
# Only first half of the ans set should remain
assert merged.data == ans_1
def test_merge_add_update(ans, upd):
crdt_1, crdt_2 = CRDT(), CRDT()
ans_1, ans_2 = slice_dict(ans, 0, len(ans) // 2), slice_dict(ans, len(ans) // 2, len(ans))
for k, v in ans_1.items():
crdt_1.add(k, v)
for k, v in ans_2.items():
crdt_2.add(k, v)
for k in ans_2:
crdt_2.update(k, upd[k])
merged = merge(crdt_1, crdt_2)
# Only keys in the second half of the ans set should be updated
ans_1.update({upd[k]:v for k, v in ans_2.items()})
assert merged.data == ans_1
def test_update_key_collision():
crdt = CRDT()
crdt.add('a', 1)
crdt.add('b', 2)
crdt.update('a', 'b')
# In this implementation of LWW the update should overwrite the original key if the key already exists
assert crdt.data == {'b': 1}
def test_merge_add_update_remove(ans, upd):
crdt_1, crdt_2 = CRDT(), CRDT()
ans_1, ans_2 = slice_dict(ans, 0, len(ans) // 2), slice_dict(ans, len(ans) // 2, len(ans))
for k, v in ans.items():
crdt_1.add(k, v)
crdt_2.add(k, v)
# Update the elements in the second half of the ans set in crdt_1 (opposite of test_merge_add_remove_update())
for k in ans_2:
crdt_1.update(k, upd[k])
# Remove old keys that are updated in crdt_1 in crdt_2 (opposite of test_merge_add_remove_update())
for k in ans_2:
crdt_2.remove(k)
merged = merge(crdt_1, crdt_2)
# Since this is a LWW set, the **removes** will overwrite the **updates** since they're executed later
assert merged.data == ans_1
def test_invalid_op():
crdt = CRDT()
operation = Operation(ts=datetime.utcnow().timestamp(), key='a', value=1, op=-1)
# Append should fail if the operation is invalid
try:
crdt.append(operation)
assert False
except AssertionError as e:
assert str(e) == INVALID_OP
def test_remove_many(ans):
crdt = CRDT()
for k, v in ans.items():
crdt.add(k, v)
for k in ans:
crdt.remove(k)
# The same set of keys is added and removed, the length of the log should be twice that of the ans set
assert len(crdt.log) == len(ans) * 2
assert len(crdt.data) == 0
def test_update_many(ans, upd):
crdt = CRDT()
for k, v in ans.items():
crdt.add(k, v)
for k, v in upd.items():
crdt.update(k, v)
# The keys are added then updated, the length of the log should be the sum of the lengths of the ans and upd set
assert len(crdt.log) == len(ans) + len(upd)
assert crdt.data == {upd[k]:v for k, v in ans.items()}
def test_add_same_key_twice():
crdt = CRDT()
key = 'a'
values = [1, 2, 3]
for v in values:
crdt.add(key, v)
assert len(crdt.log) == len(values)
# Only the updated value should be present
assert crdt.data == {key: values[-1]}
def test_update_after_remove():
crdt = CRDT()
crdt.add('a', 1)
try:
crdt.update('a', 'b')
crdt.remove('a')
# In the same instance, this operation should fail
assert False
except KeyError:
pass
def test_remove_same_key_twice():
crdt = CRDT()
crdt.add('a', 1)
try:
crdt.remove('a')
crdt.remove('a')
# In the same instance, this operation should fail
assert False
except KeyError:
pass
def test_out_of_order_append():
crdt = CRDT()
crdt.add('a', 1)
inserted = crdt.log[-1]
operation = Operation(ts=inserted.ts - 1, key=inserted.key, value=inserted.value, op=inserted.op)
# Append should fail if the timestamp of the operation is earlier than the last inserted operation
try:
crdt.append(operation)
assert False
except AssertionError as e:
assert str(e) == INVALID_TS
def __init__(self, mailbox):
self.crdt = CRDT()
self.lamport = 0
self.siteID = uuid1()
self.mailbox = mailbox