scylladb/test/cqlpy/test_keyspace.py

# Copyright 2020-present ScyllaDB
#
# SPDX-License-Identifier: LicenseRef-ScyllaDB-Source-Available-1.0

# Tests for basic keyspace operations: CREATE KEYSPACE, DROP KEYSPACE,
# ALTER KEYSPACE

from .util import new_test_keyspace, unique_name
import pytest
from cassandra.protocol import SyntaxException, AlreadyExists, InvalidRequest, ConfigurationException
from threading import Thread

from test.cluster.util import parse_replication_options, get_replication, get_replica_count


# A basic tests for successful CREATE KEYSPACE and DROP KEYSPACE
def test_create_and_drop_keyspace(cql, this_dc):
    cql.execute("CREATE KEYSPACE test_create_and_drop_keyspace WITH REPLICATION = { 'class' : 'NetworkTopologyStrategy', '" + this_dc + "' : 1 }")
    cql.execute("DROP KEYSPACE test_create_and_drop_keyspace")

def assert_keyspace(cql, keyspace, expected_class, rf_key):
    rep = get_replication(cql, keyspace)
    assert rep["class"] == expected_class
    assert get_replica_count(rep[rf_key]) == 1

# Trying to create a keyspace specifying replication options without replication strategy
# should result in NetworkTopologyStrategy being set by default.
def test_create_and_drop_keyspace_with_default_replication_class(cql, this_dc):
    with new_test_keyspace(cql, "WITH REPLICATION = { 'replication_factor' : '1' }") as keyspace:
        assert_keyspace(cql, keyspace, "org.apache.cassandra.locator.NetworkTopologyStrategy", this_dc)

# Trying to create a keyspace specifying replication options without replication factor
# should fail since SimpleStrategy does not support default replication factor
def test_create_and_drop_keyspace_simple_strategy_with_default_replication_factor(cql, this_dc):
    # create and drop a keyspace with SimpleStrategy and default replication factor
    with pytest.raises(ConfigurationException):
        with new_test_keyspace(cql, "WITH REPLICATION = { 'class' : 'SimpleStrategy' }") as keyspace:
            pass

# Trying to create a keyspace specifying replication options without replication factor
# should result in a replication factor of 1 being set by default.
def test_create_and_drop_keyspace_network_topology_strategy_with_default_replication_factor(cql, this_dc):
    with new_test_keyspace(cql, "WITH REPLICATION = { 'class' : 'NetworkTopologyStrategy' }") as keyspace:
        assert_keyspace(cql, keyspace, "org.apache.cassandra.locator.NetworkTopologyStrategy", this_dc)

# Trying to create a keyspace specifying empty replication options
# should result in NetworkTopologyStrategy and replication factor of 1 being set by default.
def test_create_and_drop_keyspace_with_default_replication_options(cql, this_dc):
    with new_test_keyspace(cql, "WITH REPLICATION = {}") as keyspace:
        assert_keyspace(cql, keyspace, "org.apache.cassandra.locator.NetworkTopologyStrategy", this_dc)

# The "WITH REPLICATION" part of CREATE KEYSPACE may be omitted.
# Trying to create a keyspace with no replication options at all
# should result in NetworkTopologyStrategy and replication factor of 1 being set by default.
def test_create_and_drop_keyspace_with_no_replication_options(cql, this_dc):
    with new_test_keyspace(cql, "") as keyspace:
        assert_keyspace(cql, keyspace, "org.apache.cassandra.locator.NetworkTopologyStrategy", this_dc)

# Trying to create the same keyspace - even if with identical parameters -
# should result in an AlreadyExists error.
def test_create_keyspace_twice(cql, this_dc):
    cql.execute("CREATE KEYSPACE test_create_keyspace_twice WITH REPLICATION = { 'class' : 'NetworkTopologyStrategy', '" + this_dc + "' : 1 }")
    with pytest.raises(AlreadyExists):
        cql.execute("CREATE KEYSPACE test_create_keyspace_twice WITH REPLICATION = { 'class' : 'NetworkTopologyStrategy', '" + this_dc + "' : 1 }")
    cql.execute("DROP KEYSPACE test_create_keyspace_twice")

# "IF NOT EXISTS" on CREATE KEYSPACE:
def test_create_keyspace_if_not_exists(cql, this_dc):
    cql.execute("CREATE KEYSPACE IF NOT EXISTS test_create_keyspace_if_not_exists WITH REPLICATION = { 'class' : 'NetworkTopologyStrategy', '" + this_dc + "' : 1 }")
    # A second invocation with IF NOT EXISTS is fine:
    cql.execute("CREATE KEYSPACE IF NOT EXISTS test_create_keyspace_if_not_exists WITH REPLICATION = { 'class' : 'NetworkTopologyStrategy', '" + this_dc + "' : 1 }")
    # It doesn't matter if the second invocation has different parameters,
    # they are ignored.
    cql.execute("CREATE KEYSPACE IF NOT EXISTS test_create_keyspace_if_not_exists WITH REPLICATION = { 'class' : 'SimpleStrategy', 'replication_factor' : 2 }")
    cql.execute("DROP KEYSPACE test_create_keyspace_if_not_exists")

# We treat ALTER to numeric RF of same count as no-op.
def test_alter_rack_list_to_same_count_numeric_rf(cql, this_dc, scylla_only):
    with new_test_keyspace(cql, f"WITH REPLICATION = {{ 'class' : 'NetworkTopologyStrategy', '{this_dc}': ['rack1'] }}") as keyspace:
        cql.execute(f"ALTER KEYSPACE {keyspace} WITH REPLICATION = {{ 'class' : 'NetworkTopologyStrategy', '{this_dc}': 1 }}")
        assert get_replication(cql, keyspace)[this_dc] == ['rack1']
        cql.execute(f"ALTER KEYSPACE {keyspace} WITH REPLICATION = {{ 'class' : 'NetworkTopologyStrategy', '{this_dc}': ['rack1'] }}")

def test_empty_rack_list_is_accepted(cql, this_dc, scylla_only):
    with new_test_keyspace(cql, f"WITH REPLICATION = {{ 'class' : 'NetworkTopologyStrategy', '{this_dc}': ['rack1'] }}") as keyspace:
        cql.execute(f"ALTER KEYSPACE {keyspace} WITH REPLICATION = {{ 'class' : 'NetworkTopologyStrategy', '{this_dc}': [] }}")
        assert this_dc not in get_replication(cql, keyspace)

def test_can_alter_rack_list_to_0(cql, this_dc, scylla_only):
    with new_test_keyspace(cql, f"WITH REPLICATION = {{ 'class' : 'NetworkTopologyStrategy', '{this_dc}': ['rack1'] }}") as keyspace:
        cql.execute(f"ALTER KEYSPACE {keyspace} WITH REPLICATION = {{ 'class' : 'NetworkTopologyStrategy', '{this_dc}': 0 }}")

def test_can_alter_to_rack_list_from_0(cql, this_dc, scylla_only):
    with new_test_keyspace(cql, f"WITH REPLICATION = {{ 'class' : 'NetworkTopologyStrategy', '{this_dc}': 0 }}") as keyspace:
        cql.execute(f"ALTER KEYSPACE {keyspace} WITH REPLICATION = {{ 'class' : 'NetworkTopologyStrategy', '{this_dc}': ['rack1'] }}")
        assert get_replication(cql, keyspace)[this_dc] == ['rack1']

# The documentation states that "Keyspace names can have alpha-
# numeric characters and contain underscores; only letters and numbers are
# supported as the first character.". This is not accurate. Test what is actually
# enforced:
def test_create_keyspace_invalid_name(cql, this_dc):
    rep = " WITH REPLICATION = { 'class' : 'NetworkTopologyStrategy', '" + this_dc + "' : 1 }"
    # The name xyz!123, unquoted, is a syntax error. With quotes it's valid
    # syntax, but an illegal name.
    with pytest.raises(SyntaxException):
        cql.execute('CREATE KEYSPACE xyz!123' + rep)
    with pytest.raises(InvalidRequest, match='name'):
        cql.execute('CREATE KEYSPACE "xyz!123"' + rep)
    # The documentation claims that only letters and numbers - i.e., not
    # underscores - are allowed as the first character of a table name.
    # This is not, in fact, true... Although an unquoted name beginning
    # with an underscore results in a syntax error in the parser, it quotes
    # such names *are* allowed:
    with pytest.raises(SyntaxException):
        cql.execute('CREATE KEYSPACE _xyz' + rep)
    cql.execute('CREATE KEYSPACE "_xyz"' + rep)
    cql.execute('DROP KEYSPACE "_xyz"')
    # As the documentation states, a keyspace name may begin with a number.
    # But such a name is not allowed by the parser, so it needs to be quoted:
    with pytest.raises(SyntaxException):
        cql.execute('CREATE KEYSPACE 123' + rep)
    cql.execute('CREATE KEYSPACE "123"' + rep)
    cql.execute('DROP KEYSPACE "123"')

# Test trying to ALTER a keyspace with invalid options.
# Reproduces #7595.
def test_create_keyspace_nonexistent_dc(cql):
    with pytest.raises(ConfigurationException):
        ks = unique_name()
        cql.execute(f"CREATE KEYSPACE {ks} WITH REPLICATION = {{ 'class' : 'NetworkTopologyStrategy', 'nonexistentdc' : 1 }}")

# Reproduces #20097
def test_create_table_in_nonexistent_keyspace(cql):
    no_ks = "nonexistent_keyspace"
    table = unique_name()
    with pytest.raises(InvalidRequest, match=no_ks):
        cql.execute(f"CREATE TABLE {no_ks}.{table} (p int PRIMARY KEY)")
    # reassert table doesn't exist
    with pytest.raises(InvalidRequest, match=no_ks):
        cql.execute(f"DROP TABLE {no_ks}.{table}")

# Test that attempts to reproduce an issue with double WITH keyword in CREATE
# KEYSPACE statement -- CASSANDRA-9565.
def test_create_keyspace_double_with(cql):
    with pytest.raises(SyntaxException):
        cql.execute('CREATE KEYSPACE WITH WITH DURABLE_WRITES = true')
    with pytest.raises(SyntaxException):
        cql.execute('CREATE KEYSPACE ks WITH WITH DURABLE_WRITES = true')

# Scylla accepts 'replication_factor' in CREATE KEYSPACE statement,
# but while CQL syntax is case-insensitive, tags within json are case-sensitive,
# hence anything else than the lowercase 'replication_factor' should be rejected.
# Reproduces #15336
def test_create_keyspace_with_case_sensitive_replication_factor_tag(cql):
    ks = unique_name()
    # lowercase 'replication_factor' should be accepted
    with new_test_keyspace(cql, "WITH REPLICATION = { 'class' : 'NetworkTopologyStrategy', 'replication_factor' : 1 }"):
        pass
    # 'replication_factor' in any other case than the lowercase should be rejected
    with pytest.raises(ConfigurationException):
        cql.execute(f"CREATE KEYSPACE {ks} WITH REPLICATION = {{ 'class' : 'NetworkTopologyStrategy', 'Replication_factor' : 1 }}")

# Test trying a non-existent keyspace - with or without the IF EXISTS flag.
# This test demonstrates a change of the exception produced between Cassandra 4.0
# and earlier versions (with Scylla behaving like the earlier versions).
def test_drop_keyspace_nonexistent(cql):
    cql.execute('DROP KEYSPACE IF EXISTS nonexistent_keyspace')
    # Cassandra changed the exception it throws on dropping a nonexistent keyspace.
    # Prior to Cassandra 4.0 (commit 207c80c1fd63dfbd8ca7e615ec8002ee8983c5d6, Nov. 2016)
    # it was a ConfigurationException, but in 4.0, it changed to and InvalidRequest.
    # In Sylla, it remains a ConfigurationException is it was in earlier Cassandra.
    with pytest.raises( (InvalidRequest, ConfigurationException) ):
        cql.execute('DROP KEYSPACE nonexistent_keyspace')

# Test trying to ALTER a keyspace.
# The test is marked as Scylla-only because Cassandra doesn't allow for RF=0 in ALL of DCs,
# which is the case here. We must use it because changing the RF in this test to any other value
# would result in an error since the keyspace would stop being RF-rack-valid.
def test_alter_keyspace(cql, this_dc, scylla_only):
    with new_test_keyspace(cql, "WITH REPLICATION = { 'class' : 'NetworkTopologyStrategy', '" + this_dc + "' : 1 }") as keyspace:
        cql.execute(f"ALTER KEYSPACE {keyspace} WITH REPLICATION = {{ 'class' : 'NetworkTopologyStrategy', '{this_dc}' : 0 }} AND DURABLE_WRITES = false")

# Test trying to ALTER RF of tablets-enabled KS by more than 1 at a time
def test_alter_keyspace_rf_by_more_than_1(cql, this_dc):
    with new_test_keyspace(cql, "WITH REPLICATION = { 'class' : 'NetworkTopologyStrategy', '" + this_dc + "' : 1 }") as keyspace:
        with pytest.raises((InvalidRequest, ConfigurationException)):
            cql.execute(f"ALTER KEYSPACE {keyspace} WITH REPLICATION = {{ 'class' : 'NetworkTopologyStrategy', '{this_dc}' : 3 }} AND DURABLE_WRITES = false")

# Test trying to ALTER a tablets-enabled KS by providing the 'replication_factor' tag
def test_alter_keyspace_with_replication_factor_tag(cql):
    with new_test_keyspace(cql, "WITH REPLICATION = { 'class' : 'NetworkTopologyStrategy', 'replication_factor' : 1 }") as keyspace:
        with pytest.raises((InvalidRequest, ConfigurationException)):
            cql.execute(f"ALTER KEYSPACE {keyspace} WITH REPLICATION = {{ 'class' : 'NetworkTopologyStrategy', 'replication_factor' : 2 }}")

# Test trying to ALTER a keyspace with invalid options.
def test_alter_keyspace_invalid(cql, this_dc):
    with new_test_keyspace(cql, "WITH REPLICATION = { 'class' : 'NetworkTopologyStrategy', '" + this_dc + "' : 1 }") as keyspace:
        with pytest.raises(ConfigurationException):
            cql.execute(f"ALTER KEYSPACE {keyspace} WITH REPLICATION = {{ 'class' : 'NoSuchStrategy' }}")

# Continuing test_alter_keyspace_invalid, this is another invalid alter
# keyspace: SimpleStrategy, if not outright forbidden, requires a
# replication_factor option. However, this is only true in Scylla - in
# Cassandra 4.1 and above, a missing replication_factor *is* allowed,
# because there is a default_keyspace_rf configuration. See issue #16028.
def test_alter_keyspace_missing_rf(cql, this_dc, scylla_only, has_tablets):
    if has_tablets:
        extra_opts = " AND TABLETS = {'enabled': false}"
    else:
        extra_opts = ""
    with new_test_keyspace(cql, "WITH REPLICATION = { 'class' : 'NetworkTopologyStrategy', '" + this_dc + "' : 1 }" + extra_opts) as keyspace:
        # SimpleStrategy, if not outright forbidden, requires a
        # replication_factor option.
        with pytest.raises(ConfigurationException):
            cql.execute(f"ALTER KEYSPACE {keyspace} WITH REPLICATION = {{ 'class' : 'SimpleStrategy' }}")
        # Strangely, Cassandra doesn't raise here - it allows garbage
        # replication_factor (and probably uses the default instead).
        # this should probably be considered a Cassandra bug.
        with pytest.raises(ConfigurationException):
            cql.execute(f"ALTER KEYSPACE {keyspace} WITH REPLICATION = {{ 'class' : 'NetworkTopologyStrategy', 'replication_factor' : 'foo' }}")

# Test trying to ALTER a keyspace with invalid options.
# Reproduces #7595.
def test_alter_keyspace_nonexistent_dc(cql, this_dc):
    with new_test_keyspace(cql, "WITH REPLICATION = { 'class' : 'NetworkTopologyStrategy', '" + this_dc + "' : 1 }") as keyspace:
        with pytest.raises(ConfigurationException):
            cql.execute(f"ALTER KEYSPACE {keyspace} WITH replication = {{ 'class' : 'NetworkTopologyStrategy', 'nonexistentdc' : 1 }}")

# Test trying to ALTER a non-existing keyspace
def test_alter_keyspace_nonexisting(cql, this_dc):
    cql.execute('DROP KEYSPACE IF EXISTS nonexistent_keyspace')
    with pytest.raises(InvalidRequest):
        cql.execute("ALTER KEYSPACE nonexistent_keyspace WITH REPLICATION = { 'class' : 'NetworkTopologyStrategy', '" + this_dc + "' : 1 }")

# Test that attempts to reproduce an issue with double WITH keyword in ALTER
# KEYSPACE statement -- CASSANDRA-9565.
def test_alter_keyspace_double_with(cql):
    with pytest.raises(SyntaxException):
        cql.execute('ALTER KEYSPACE WITH WITH DURABLE_WRITES = true')
    with pytest.raises(SyntaxException):
        cql.execute('ALTER KEYSPACE ks WITH WITH DURABLE_WRITES = true')

# Reproducer for issue #8968: We have two threads, one thread loops trying to
# create a keyspace and a table in it, and the other thread loops trying to
# delete this keyspace. Obviously some of these operations are expected to
# fail - we can't create an already-existing keyspace if its deletion hasn't
# yet finished, and we can't create a table in a keyspace which was just
# deleted. But we expect that at the end of the test the database remains in
# some valid state - the keyspace should either exist or not exist. It
# shouldn't be in some broken immortal state as reported in issue #8968.
def test_concurrent_create_and_drop_keyspace(cql, this_dc, fails_without_consistent_cluster_management):
    ksdef = "WITH REPLICATION = { 'class' : 'NetworkTopologyStrategy', '" + this_dc + "' : 1 }"
    cfdef = "(a int PRIMARY KEY)"
    with new_test_keyspace(cql, ksdef) as keyspace:
        # The more iterations we do, the higher the chance of reproducing
        # this issue. On my laptop, count = 40 reproduces the bug every time.
        # Lower numbers have some chance of not catching the bug. If this
        # issue starts to xpass, we may need to increase the count.
        count = 40
        def drops(count):
            for i in range(count):
                try:
                    cql.execute(f"DROP KEYSPACE {keyspace}")
                except Exception as e: print(e)
                else: print("drop successful")
        def creates(count):
            for i in range(count):
                try:
                    cql.execute(f"CREATE KEYSPACE {keyspace} {ksdef}")
                    print("create keyspace successful")
                    # Create a table in this keyspace. This creation may
                    # race with deletion of the entire keyspace by the
                    # parallel thread. Reproducing #8968 requires this
                    # operation - just creating and deleting the keyspace
                    # without anything in it did not reproduce the problem.
                    cql.execute(f"CREATE TABLE {keyspace}.xyz {cfdef}")
                except Exception as e: print(e)
                else: print("create table successful")
        t1 = Thread(target=drops, args=[count])
        t2 = Thread(target=creates, args=[count])
        t1.start()
        t2.start()
        t1.join()
        t2.join()
        # At this point, the keyspace should either exist, or not exist.
        # So CREATE KEYSPACE IF NOT EXIST should ensure it does exist,
        # and then one DROP KEYSPACE should succeed, a second one should
        # fail, and finally we can recreate the keyspace as new_test_keyspace
        # expects it.
        # If any of the following statements fail, it means we reached an
        # invalid state. This is issue #8968.
        cql.execute(f"CREATE KEYSPACE IF NOT EXISTS {keyspace} {ksdef}")
        cql.execute(f"DROP KEYSPACE {keyspace}")
        # See explanation above how different versions of Cassandra and
        # Scylla produce different errors when dropping a non-existent ks:
        with pytest.raises( (InvalidRequest, ConfigurationException) ):
            cql.execute(f"DROP KEYSPACE {keyspace}")
        cql.execute(f"CREATE KEYSPACE {keyspace} {ksdef}")

# Test that passing "LOCAL" parameter to storage options works as expected
# and is not explicitly stored - since it's equal to the original storage
def test_storage_options_local(cql, scylla_only):
    ksdef = "WITH REPLICATION = { 'class' : 'NetworkTopologyStrategy', 'replication_factor' : '1' } " \
            "AND STORAGE = { 'type' : 'LOCAL' }"

    def row_has_storage_options(row):
        o = getattr(row, 'storage_options', None)
        t = getattr(row, 'storage_type', None)
        return t is not None or o is not None

    with new_test_keyspace(cql, ksdef) as keyspace:
        res = list(cql.execute(f"SELECT * FROM system_schema.scylla_keyspaces WHERE keyspace_name = '{keyspace}'"))
        assert not res or not row_has_storage_options(res[0])

# Test that passing an unsupported storage type is not legal
def test_storage_options_unknown_type(cql, scylla_only):
    ksdef = "WITH REPLICATION = { 'class' : 'NetworkTopologyStrategy', 'replication_factor' : '1' } " \
            "AND STORAGE = { 'type' : 'S4', 'bucket' : '42', 'endpoint' : 'localhost' }"
    with pytest.raises(InvalidRequest):
        with new_test_keyspace(cql, ksdef):
            pass

# Test that passing nonexistent options results in an error
def test_storage_options_nonexistent_param(cql, scylla_only):
    ksdef = "WITH REPLICATION = { 'class' : 'NetworkTopologyStrategy', 'replication_factor' : '1' } " \
            "AND STORAGE = { 'type' : 'S3', 'bucket' : '42', 'endpoint' : 'localhost', 'superfluous' : 'info' }"
    with pytest.raises(InvalidRequest):
        with new_test_keyspace(cql, ksdef):
            pass
    ksdef = "WITH REPLICATION = { 'class' : 'NetworkTopologyStrategy', 'replication_factor' : '1' } " \
            "AND STORAGE = { 'type' : 'LOCAL', 'superfluous' : 'info' }"
    with pytest.raises(InvalidRequest):
        with new_test_keyspace(cql, ksdef):
            pass

# Test that not passing required parameters fails
def test_storage_options_required_param(cql, scylla_only):
    ksdef = "WITH REPLICATION = { 'class' : 'NetworkTopologyStrategy', 'replication_factor' : '1' } " \
            "AND STORAGE = { 'type' : 'S3', 'bucket' : '42' }"
    with pytest.raises(InvalidRequest):
        with new_test_keyspace(cql, ksdef):
            pass

# Test that storage options cannot be altered (at least until it's well defined
# what it means to e.g. switch from S3 to another format and back).
def test_storage_options_alter_type(cql, scylla_only):
    ksdef = "WITH REPLICATION = { 'class' : 'NetworkTopologyStrategy', 'replication_factor' : '1' } " \
            "AND STORAGE = { 'type' : 'LOCAL' }"
    with new_test_keyspace(cql, ksdef) as keyspace:
         # It's not fine to change the storage type
        ksdef_local = "WITH REPLICATION = { 'class' : 'NetworkTopologyStrategy', 'replication_factor' : '1' } " \
            "AND STORAGE = { 'type' : 'S3', 'bucket' : '/b1', 'endpoint': 'localhost'}"
        with pytest.raises(InvalidRequest):
            res = cql.execute(f"ALTER KEYSPACE {keyspace} {ksdef_local}")

# Reproducer for scylladb#14139
def test_alter_keyspace_preserves_udt(cql):
    ks = unique_name()
    cql.execute(f"CREATE KEYSPACE {ks} WITH REPLICATION = {{'class': 'NetworkTopologyStrategy', 'replication_factor': 1}}")
    try:
        cql.execute(f"CREATE TYPE {ks}.my_type (my_field int)")
        cql.execute(f"CREATE TABLE {ks}.tab (p int PRIMARY KEY, m {ks}.my_type)")
        # The contents of the below line doesn't matter, only the fact
        # that it modifies keyspace metadata.
        cql.execute(f"ALTER KEYSPACE {ks} WITH DURABLE_WRITES = false")
        # The root cause of #14139 was that ALTER KEYSPACE was dropping
        # some in-memory metadata about UDTs
        cql.execute(f"DESCRIBE TYPE {ks}.my_type")
        # #14139 was originally observed as some schema manipulations,
        # such as DROP TABLE, failing after the ALTER KEYSPACE.
        cql.execute(f"DROP TABLE {ks}.tab")
    finally:
        cql.execute(f"DROP TABLE IF EXISTS {ks}.tab")
        cql.execute(f"DROP KEYSPACE {ks}")

# Previously, CREATE KEYSPACE warned about unsupported features with tablets, telling
# the user they may want to consider creating the keyspace without tablets.
# Now that there are no unsupported features, check that no warning is produced.
def test_create_keyspace_no_warn_tablets(cql, scylla_only, skip_without_tablets):
    keyspace = unique_name()
    try:
        # When this test isn't skipped, creating a keyspace without any
        # tablet parameters uses tablets by default - and should not produce a
        # warning:
        f = cql.execute_async("CREATE KEYSPACE " + keyspace + " WITH REPLICATION = { 'class' : 'NetworkTopologyStrategy', 'replication_factor' : 1 }")
        f.result() # results must be consumed before fetching warnings
        assert not f.warnings or 'tablets' not in '\n'.join(f.warnings)
        cql.execute(f"DROP KEYSPACE {keyspace}")
        # If we explicitly ask for tablets, we also don't get a warning:
        f = cql.execute_async("CREATE KEYSPACE " + keyspace + " WITH REPLICATION = { 'class' : 'NetworkTopologyStrategy', 'replication_factor' : 1 } AND TABLETS = { 'enabled': true }")
        f.result()
        assert not f.warnings or 'tablets' not in '\n'.join(f.warnings)
        cql.execute(f"DROP KEYSPACE {keyspace}")
        # If we explicitly ask to disable tablets, no warning:
        f = cql.execute_async("CREATE KEYSPACE " + keyspace + " WITH REPLICATION = { 'class' : 'NetworkTopologyStrategy', 'replication_factor' : 1 } AND TABLETS = { 'enabled': false }")
        f.result()
        assert not f.warnings or 'tablets' not in '\n'.join(f.warnings)
        cql.execute(f"DROP KEYSPACE {keyspace}")
    finally:
        cql.execute(f"DROP KEYSPACE IF EXISTS {keyspace}")

# TODO: more tests for "WITH REPLICATION" syntax in CREATE TABLE.
# TODO: check the "AND DURABLE_WRITES" option of CREATE TABLE.
# TODO: confirm case insensitivity without quotes, and case sensitivity with them.