def test_student_sharding(self):
# Ensure empty starting DB
result = DeploymentConfig().query().fetch(limit=None)
self.assertFalse(result)
result = Student().query().fetch(limit=None)
self.assertFalse(result)
result = StudentShard().query().fetch(limit=None)
self.assertFalse(result)
# Test creation of dummy deployment config
config = get_dummy_config()
result = DeploymentConfig().query().fetch(limit=None)
self.assertEqual(1, len(result))
# Create/delete shards
shard_count = len(get_dummy_ids())
setup_dummy_shards()
result = StudentShard().query().fetch(limit=None)
self.assertEqual(shard_count, len(result))
self.assertEqual(shard_count, len(StudentShard.get_all()))
StudentShard.delete_all()
self.assertFalse(StudentShard.get_all())
# Linear shard generator serves each shard once
setup_dummy_shards()
seen_shards = {}
gen = StudentShard.linear_shard_generator
for i in gen():
seen_shards[i.key] = True
self.assertEqual(shard_count, len(seen_shards))
# Circular shard generator serves each shard once, then loops
seen_shards = {}
gen = StudentShard.circular_shard_generator
failsafe = 10000
count = 0
try:
for i in gen():
count += 1
if count > failsafe:
raise ValueError("Infinite loop when testing circular_shard_generator")
if i.key in seen_shards:
raise StopIteration("Shard repeat")
else:
seen_shards[i.key] = True
except StopIteration:
pass
self.assertEqual(shard_count, len(seen_shards))
