moto/tests/test_emr/test_emr.py

from __future__ import unicode_literals
import time
from datetime import datetime

import boto
import pytz
from boto.emr.bootstrap_action import BootstrapAction
from boto.emr.instance_group import InstanceGroup
from boto.emr.step import StreamingStep

import six
import sure  # noqa

from moto import mock_emr_deprecated
from tests.helpers import requires_boto_gte


run_jobflow_args = dict(
    job_flow_role='EMR_EC2_DefaultRole',
    keep_alive=True,
    log_uri='s3://some_bucket/jobflow_logs',
    master_instance_type='c1.medium',
    name='My jobflow',
    num_instances=2,
    service_role='EMR_DefaultRole',
    slave_instance_type='c1.medium',
)


input_instance_groups = [
    InstanceGroup(1, 'MASTER', 'c1.medium', 'ON_DEMAND', 'master'),
    InstanceGroup(3, 'CORE', 'c1.medium', 'ON_DEMAND', 'core'),
    InstanceGroup(6, 'TASK', 'c1.large', 'SPOT', 'task-1', '0.07'),
    InstanceGroup(10, 'TASK', 'c1.xlarge', 'SPOT', 'task-2', '0.05'),
]


@mock_emr_deprecated
def test_describe_cluster():
    conn = boto.connect_emr()
    args = run_jobflow_args.copy()
    args.update(dict(
        api_params={
            'Applications.member.1.Name': 'Spark',
            'Applications.member.1.Version': '2.4.2',
            'Configurations.member.1.Classification': 'yarn-site',
            'Configurations.member.1.Properties.entry.1.key': 'someproperty',
            'Configurations.member.1.Properties.entry.1.value': 'somevalue',
            'Configurations.member.1.Properties.entry.2.key': 'someotherproperty',
            'Configurations.member.1.Properties.entry.2.value': 'someothervalue',
            'Instances.EmrManagedMasterSecurityGroup': 'master-security-group',
            'Instances.Ec2SubnetId': 'subnet-8be41cec',
        },
        availability_zone='us-east-2b',
        ec2_keyname='mykey',
        job_flow_role='EMR_EC2_DefaultRole',
        keep_alive=False,
        log_uri='s3://some_bucket/jobflow_logs',
        name='My jobflow',
        service_role='EMR_DefaultRole',
        visible_to_all_users=True,
    ))
    cluster_id = conn.run_jobflow(**args)
    input_tags = {'tag1': 'val1', 'tag2': 'val2'}
    conn.add_tags(cluster_id, input_tags)

    cluster = conn.describe_cluster(cluster_id)
    cluster.applications[0].name.should.equal('Spark')
    cluster.applications[0].version.should.equal('2.4.2')
    cluster.autoterminate.should.equal('true')

    # configurations appear not be supplied as attributes?

    attrs = cluster.ec2instanceattributes
    # AdditionalMasterSecurityGroups
    # AdditionalSlaveSecurityGroups
    attrs.ec2availabilityzone.should.equal(args['availability_zone'])
    attrs.ec2keyname.should.equal(args['ec2_keyname'])
    attrs.ec2subnetid.should.equal(args['api_params']['Instances.Ec2SubnetId'])
    # EmrManagedMasterSecurityGroups
    # EmrManagedSlaveSecurityGroups
    attrs.iaminstanceprofile.should.equal(args['job_flow_role'])
    # ServiceAccessSecurityGroup

    cluster.id.should.equal(cluster_id)
    cluster.loguri.should.equal(args['log_uri'])
    cluster.masterpublicdnsname.should.be.a(six.string_types)
    cluster.name.should.equal(args['name'])
    int(cluster.normalizedinstancehours).should.equal(0)
    # cluster.release_label
    cluster.shouldnt.have.property('requestedamiversion')
    cluster.runningamiversion.should.equal('1.0.0')
    # cluster.securityconfiguration
    cluster.servicerole.should.equal(args['service_role'])

    cluster.status.state.should.equal('TERMINATED')
    cluster.status.statechangereason.message.should.be.a(six.string_types)
    cluster.status.statechangereason.code.should.be.a(six.string_types)
    cluster.status.timeline.creationdatetime.should.be.a(six.string_types)
    # cluster.status.timeline.enddatetime.should.be.a(six.string_types)
    # cluster.status.timeline.readydatetime.should.be.a(six.string_types)

    dict((item.key, item.value)
         for item in cluster.tags).should.equal(input_tags)

    cluster.terminationprotected.should.equal('false')
    cluster.visibletoallusers.should.equal('true')


@mock_emr_deprecated
def test_describe_jobflows():
    conn = boto.connect_emr()
    args = run_jobflow_args.copy()
    expected = {}

    for idx in range(4):
        cluster_name = 'cluster' + str(idx)
        args['name'] = cluster_name
        cluster_id = conn.run_jobflow(**args)
        expected[cluster_id] = {
            'id': cluster_id,
            'name': cluster_name,
            'state': 'WAITING'
        }

    # need sleep since it appears the timestamp is always rounded to
    # the nearest second internally
    time.sleep(1)
    timestamp = datetime.now(pytz.utc)
    time.sleep(1)

    for idx in range(4, 6):
        cluster_name = 'cluster' + str(idx)
        args['name'] = cluster_name
        cluster_id = conn.run_jobflow(**args)
        conn.terminate_jobflow(cluster_id)
        expected[cluster_id] = {
            'id': cluster_id,
            'name': cluster_name,
            'state': 'TERMINATED'
        }
    jobs = conn.describe_jobflows()
    jobs.should.have.length_of(6)

    for cluster_id, y in expected.items():
        resp = conn.describe_jobflows(jobflow_ids=[cluster_id])
        resp.should.have.length_of(1)
        resp[0].jobflowid.should.equal(cluster_id)

    resp = conn.describe_jobflows(states=['WAITING'])
    resp.should.have.length_of(4)
    for x in resp:
        x.state.should.equal('WAITING')

    resp = conn.describe_jobflows(created_before=timestamp)
    resp.should.have.length_of(4)

    resp = conn.describe_jobflows(created_after=timestamp)
    resp.should.have.length_of(2)


@mock_emr_deprecated
def test_describe_jobflow():
    conn = boto.connect_emr()
    args = run_jobflow_args.copy()
    args.update(dict(
        ami_version='3.8.1',
        api_params={
            #'Applications.member.1.Name': 'Spark',
            #'Applications.member.1.Version': '2.4.2',
            #'Configurations.member.1.Classification': 'yarn-site',
            #'Configurations.member.1.Properties.entry.1.key': 'someproperty',
            #'Configurations.member.1.Properties.entry.1.value': 'somevalue',
            #'Instances.EmrManagedMasterSecurityGroup': 'master-security-group',
            'Instances.Ec2SubnetId': 'subnet-8be41cec',
        },
        ec2_keyname='mykey',
        hadoop_version='2.4.0',

        name='My jobflow',
        log_uri='s3://some_bucket/jobflow_logs',
        keep_alive=True,
        master_instance_type='c1.medium',
        slave_instance_type='c1.medium',
        num_instances=2,

        availability_zone='us-west-2b',

        job_flow_role='EMR_EC2_DefaultRole',
        service_role='EMR_DefaultRole',
        visible_to_all_users=True,
    ))

    cluster_id = conn.run_jobflow(**args)
    jf = conn.describe_jobflow(cluster_id)
    jf.amiversion.should.equal(args['ami_version'])
    jf.bootstrapactions.should.equal(None)
    jf.creationdatetime.should.be.a(six.string_types)
    jf.should.have.property('laststatechangereason')
    jf.readydatetime.should.be.a(six.string_types)
    jf.startdatetime.should.be.a(six.string_types)
    jf.state.should.equal('WAITING')

    jf.ec2keyname.should.equal(args['ec2_keyname'])
    # Ec2SubnetId
    jf.hadoopversion.should.equal(args['hadoop_version'])
    int(jf.instancecount).should.equal(2)

    for ig in jf.instancegroups:
        ig.creationdatetime.should.be.a(six.string_types)
        # ig.enddatetime.should.be.a(six.string_types)
        ig.should.have.property('instancegroupid').being.a(six.string_types)
        int(ig.instancerequestcount).should.equal(1)
        ig.instancerole.should.be.within(['MASTER', 'CORE'])
        int(ig.instancerunningcount).should.equal(1)
        ig.instancetype.should.equal('c1.medium')
        ig.laststatechangereason.should.be.a(six.string_types)
        ig.market.should.equal('ON_DEMAND')
        ig.name.should.be.a(six.string_types)
        ig.readydatetime.should.be.a(six.string_types)
        ig.startdatetime.should.be.a(six.string_types)
        ig.state.should.equal('RUNNING')

    jf.keepjobflowalivewhennosteps.should.equal('true')
    jf.masterinstanceid.should.be.a(six.string_types)
    jf.masterinstancetype.should.equal(args['master_instance_type'])
    jf.masterpublicdnsname.should.be.a(six.string_types)
    int(jf.normalizedinstancehours).should.equal(0)
    jf.availabilityzone.should.equal(args['availability_zone'])
    jf.slaveinstancetype.should.equal(args['slave_instance_type'])
    jf.terminationprotected.should.equal('false')

    jf.jobflowid.should.equal(cluster_id)
    # jf.jobflowrole.should.equal(args['job_flow_role'])
    jf.loguri.should.equal(args['log_uri'])
    jf.name.should.equal(args['name'])
    # jf.servicerole.should.equal(args['service_role'])

    jf.steps.should.have.length_of(0)

    list(i.value for i in jf.supported_products).should.equal([])
    jf.visibletoallusers.should.equal('true')


@mock_emr_deprecated
def test_list_clusters():
    conn = boto.connect_emr()
    args = run_jobflow_args.copy()
    expected = {}

    for idx in range(40):
        cluster_name = 'jobflow' + str(idx)
        args['name'] = cluster_name
        cluster_id = conn.run_jobflow(**args)
        expected[cluster_id] = {
            'id': cluster_id,
            'name': cluster_name,
            'normalizedinstancehours': '0',
            'state': 'WAITING'
        }

    # need sleep since it appears the timestamp is always rounded to
    # the nearest second internally
    time.sleep(1)
    timestamp = datetime.now(pytz.utc)
    time.sleep(1)

    for idx in range(40, 70):
        cluster_name = 'jobflow' + str(idx)
        args['name'] = cluster_name
        cluster_id = conn.run_jobflow(**args)
        conn.terminate_jobflow(cluster_id)
        expected[cluster_id] = {
            'id': cluster_id,
            'name': cluster_name,
            'normalizedinstancehours': '0',
            'state': 'TERMINATED'
        }

    args = {}
    while 1:
        resp = conn.list_clusters(**args)
        clusters = resp.clusters
        len(clusters).should.be.lower_than_or_equal_to(50)
        for x in clusters:
            y = expected[x.id]
            x.id.should.equal(y['id'])
            x.name.should.equal(y['name'])
            x.normalizedinstancehours.should.equal(
                y['normalizedinstancehours'])
            x.status.state.should.equal(y['state'])
            x.status.timeline.creationdatetime.should.be.a(six.string_types)
            if y['state'] == 'TERMINATED':
                x.status.timeline.enddatetime.should.be.a(six.string_types)
            else:
                x.status.timeline.shouldnt.have.property('enddatetime')
            x.status.timeline.readydatetime.should.be.a(six.string_types)
        if not hasattr(resp, 'marker'):
            break
        args = {'marker': resp.marker}

    resp = conn.list_clusters(cluster_states=['TERMINATED'])
    resp.clusters.should.have.length_of(30)
    for x in resp.clusters:
        x.status.state.should.equal('TERMINATED')

    resp = conn.list_clusters(created_before=timestamp)
    resp.clusters.should.have.length_of(40)

    resp = conn.list_clusters(created_after=timestamp)
    resp.clusters.should.have.length_of(30)


@mock_emr_deprecated
def test_run_jobflow():
    conn = boto.connect_emr()
    args = run_jobflow_args.copy()
    job_id = conn.run_jobflow(**args)
    job_flow = conn.describe_jobflow(job_id)
    job_flow.state.should.equal('WAITING')
    job_flow.jobflowid.should.equal(job_id)
    job_flow.name.should.equal(args['name'])
    job_flow.masterinstancetype.should.equal(args['master_instance_type'])
    job_flow.slaveinstancetype.should.equal(args['slave_instance_type'])
    job_flow.loguri.should.equal(args['log_uri'])
    job_flow.visibletoallusers.should.equal('false')
    int(job_flow.normalizedinstancehours).should.equal(0)
    job_flow.steps.should.have.length_of(0)


@mock_emr_deprecated
def test_run_jobflow_in_multiple_regions():
    regions = {}
    for region in ['us-east-1', 'eu-west-1']:
        conn = boto.emr.connect_to_region(region)
        args = run_jobflow_args.copy()
        args['name'] = region
        cluster_id = conn.run_jobflow(**args)
        regions[region] = {'conn': conn, 'cluster_id': cluster_id}

    for region in regions.keys():
        conn = regions[region]['conn']
        jf = conn.describe_jobflow(regions[region]['cluster_id'])
        jf.name.should.equal(region)


@requires_boto_gte("2.8")
@mock_emr_deprecated
def test_run_jobflow_with_new_params():
    # Test that run_jobflow works with newer params
    conn = boto.connect_emr()
    conn.run_jobflow(**run_jobflow_args)


@requires_boto_gte("2.8")
@mock_emr_deprecated
def test_run_jobflow_with_visible_to_all_users():
    conn = boto.connect_emr()
    for expected in (True, False):
        job_id = conn.run_jobflow(
            visible_to_all_users=expected,
            **run_jobflow_args
        )
        job_flow = conn.describe_jobflow(job_id)
        job_flow.visibletoallusers.should.equal(str(expected).lower())


@requires_boto_gte("2.8")
@mock_emr_deprecated
def test_run_jobflow_with_instance_groups():
    input_groups = dict((g.name, g) for g in input_instance_groups)
    conn = boto.connect_emr()
    job_id = conn.run_jobflow(instance_groups=input_instance_groups,
                              **run_jobflow_args)
    job_flow = conn.describe_jobflow(job_id)
    int(job_flow.instancecount).should.equal(
        sum(g.num_instances for g in input_instance_groups))
    for instance_group in job_flow.instancegroups:
        expected = input_groups[instance_group.name]
        instance_group.should.have.property('instancegroupid')
        int(instance_group.instancerunningcount).should.equal(
            expected.num_instances)
        instance_group.instancerole.should.equal(expected.role)
        instance_group.instancetype.should.equal(expected.type)
        instance_group.market.should.equal(expected.market)
        if hasattr(expected, 'bidprice'):
            instance_group.bidprice.should.equal(expected.bidprice)


@requires_boto_gte("2.8")
@mock_emr_deprecated
def test_set_termination_protection():
    conn = boto.connect_emr()
    job_id = conn.run_jobflow(**run_jobflow_args)
    job_flow = conn.describe_jobflow(job_id)
    job_flow.terminationprotected.should.equal('false')

    conn.set_termination_protection(job_id, True)
    job_flow = conn.describe_jobflow(job_id)
    job_flow.terminationprotected.should.equal('true')

    conn.set_termination_protection(job_id, False)
    job_flow = conn.describe_jobflow(job_id)
    job_flow.terminationprotected.should.equal('false')


@requires_boto_gte("2.8")
@mock_emr_deprecated
def test_set_visible_to_all_users():
    conn = boto.connect_emr()
    args = run_jobflow_args.copy()
    args['visible_to_all_users'] = False
    job_id = conn.run_jobflow(**args)
    job_flow = conn.describe_jobflow(job_id)
    job_flow.visibletoallusers.should.equal('false')

    conn.set_visible_to_all_users(job_id, True)
    job_flow = conn.describe_jobflow(job_id)
    job_flow.visibletoallusers.should.equal('true')

    conn.set_visible_to_all_users(job_id, False)
    job_flow = conn.describe_jobflow(job_id)
    job_flow.visibletoallusers.should.equal('false')


@mock_emr_deprecated
def test_terminate_jobflow():
    conn = boto.connect_emr()
    job_id = conn.run_jobflow(**run_jobflow_args)
    flow = conn.describe_jobflows()[0]
    flow.state.should.equal('WAITING')

    conn.terminate_jobflow(job_id)
    flow = conn.describe_jobflows()[0]
    flow.state.should.equal('TERMINATED')


# testing multiple end points for each feature

@mock_emr_deprecated
def test_bootstrap_actions():
    bootstrap_actions = [
        BootstrapAction(
            name='bs1',
            path='path/to/script',
            bootstrap_action_args=['arg1', 'arg2&arg3']),
        BootstrapAction(
            name='bs2',
            path='path/to/anotherscript',
            bootstrap_action_args=[])
    ]

    conn = boto.connect_emr()
    cluster_id = conn.run_jobflow(
        bootstrap_actions=bootstrap_actions,
        **run_jobflow_args
    )

    jf = conn.describe_jobflow(cluster_id)
    for x, y in zip(jf.bootstrapactions, bootstrap_actions):
        x.name.should.equal(y.name)
        x.path.should.equal(y.path)
        list(o.value for o in x.args).should.equal(y.args())

    resp = conn.list_bootstrap_actions(cluster_id)
    for i, y in enumerate(bootstrap_actions):
        x = resp.actions[i]
        x.name.should.equal(y.name)
        x.scriptpath.should.equal(y.path)
        list(arg.value for arg in x.args).should.equal(y.args())


@mock_emr_deprecated
def test_instance_groups():
    input_groups = dict((g.name, g) for g in input_instance_groups)

    conn = boto.connect_emr()
    args = run_jobflow_args.copy()
    for key in ['master_instance_type', 'slave_instance_type', 'num_instances']:
        del args[key]
    args['instance_groups'] = input_instance_groups[:2]
    job_id = conn.run_jobflow(**args)

    jf = conn.describe_jobflow(job_id)
    base_instance_count = int(jf.instancecount)

    conn.add_instance_groups(job_id, input_instance_groups[2:])

    jf = conn.describe_jobflow(job_id)
    int(jf.instancecount).should.equal(
        sum(g.num_instances for g in input_instance_groups))
    for x in jf.instancegroups:
        y = input_groups[x.name]
        if hasattr(y, 'bidprice'):
            x.bidprice.should.equal(y.bidprice)
        x.creationdatetime.should.be.a(six.string_types)
        # x.enddatetime.should.be.a(six.string_types)
        x.should.have.property('instancegroupid')
        int(x.instancerequestcount).should.equal(y.num_instances)
        x.instancerole.should.equal(y.role)
        int(x.instancerunningcount).should.equal(y.num_instances)
        x.instancetype.should.equal(y.type)
        x.laststatechangereason.should.be.a(six.string_types)
        x.market.should.equal(y.market)
        x.name.should.be.a(six.string_types)
        x.readydatetime.should.be.a(six.string_types)
        x.startdatetime.should.be.a(six.string_types)
        x.state.should.equal('RUNNING')

    for x in conn.list_instance_groups(job_id).instancegroups:
        y = input_groups[x.name]
        if hasattr(y, 'bidprice'):
            x.bidprice.should.equal(y.bidprice)
        # Configurations
        # EbsBlockDevices
        # EbsOptimized
        x.should.have.property('id')
        x.instancegrouptype.should.equal(y.role)
        x.instancetype.should.equal(y.type)
        x.market.should.equal(y.market)
        x.name.should.equal(y.name)
        int(x.requestedinstancecount).should.equal(y.num_instances)
        int(x.runninginstancecount).should.equal(y.num_instances)
        # ShrinkPolicy
        x.status.state.should.equal('RUNNING')
        x.status.statechangereason.code.should.be.a(six.string_types)
        x.status.statechangereason.message.should.be.a(six.string_types)
        x.status.timeline.creationdatetime.should.be.a(six.string_types)
        # x.status.timeline.enddatetime.should.be.a(six.string_types)
        x.status.timeline.readydatetime.should.be.a(six.string_types)

    igs = dict((g.name, g) for g in jf.instancegroups)

    conn.modify_instance_groups(
        [igs['task-1'].instancegroupid, igs['task-2'].instancegroupid],
        [2, 3])
    jf = conn.describe_jobflow(job_id)
    int(jf.instancecount).should.equal(base_instance_count + 5)
    igs = dict((g.name, g) for g in jf.instancegroups)
    int(igs['task-1'].instancerunningcount).should.equal(2)
    int(igs['task-2'].instancerunningcount).should.equal(3)


@mock_emr_deprecated
def test_steps():
    input_steps = [
        StreamingStep(
            name='My wordcount example',
            mapper='s3n://elasticmapreduce/samples/wordcount/wordSplitter.py',
            reducer='aggregate',
            input='s3n://elasticmapreduce/samples/wordcount/input',
            output='s3n://output_bucket/output/wordcount_output'),
        StreamingStep(
            name='My wordcount example & co.',
            mapper='s3n://elasticmapreduce/samples/wordcount/wordSplitter2.py',
            reducer='aggregate',
            input='s3n://elasticmapreduce/samples/wordcount/input2',
            output='s3n://output_bucket/output/wordcount_output2')
    ]

    # TODO: implementation and test for cancel_steps

    conn = boto.connect_emr()
    cluster_id = conn.run_jobflow(
        steps=[input_steps[0]],
        **run_jobflow_args)

    jf = conn.describe_jobflow(cluster_id)
    jf.steps.should.have.length_of(1)

    conn.add_jobflow_steps(cluster_id, [input_steps[1]])

    jf = conn.describe_jobflow(cluster_id)
    jf.steps.should.have.length_of(2)
    for step in jf.steps:
        step.actiononfailure.should.equal('TERMINATE_JOB_FLOW')
        list(arg.value for arg in step.args).should.have.length_of(8)
        step.creationdatetime.should.be.a(six.string_types)
        # step.enddatetime.should.be.a(six.string_types)
        step.jar.should.equal(
            '/home/hadoop/contrib/streaming/hadoop-streaming.jar')
        step.laststatechangereason.should.be.a(six.string_types)
        step.mainclass.should.equal('')
        step.name.should.be.a(six.string_types)
        # step.readydatetime.should.be.a(six.string_types)
        # step.startdatetime.should.be.a(six.string_types)
        step.state.should.be.within(['STARTING', 'PENDING'])

    expected = dict((s.name, s) for s in input_steps)

    steps = conn.list_steps(cluster_id).steps
    for x in steps:
        y = expected[x.name]
        # actiononfailure
        list(arg.value for arg in x.config.args).should.equal([
            '-mapper', y.mapper,
            '-reducer', y.reducer,
            '-input', y.input,
            '-output', y.output,
        ])
        x.config.jar.should.equal(
            '/home/hadoop/contrib/streaming/hadoop-streaming.jar')
        x.config.mainclass.should.equal('')
        # properties
        x.should.have.property('id').should.be.a(six.string_types)
        x.name.should.equal(y.name)
        x.status.state.should.be.within(['STARTING', 'PENDING'])
        # x.status.statechangereason
        x.status.timeline.creationdatetime.should.be.a(six.string_types)
        # x.status.timeline.enddatetime.should.be.a(six.string_types)
        # x.status.timeline.startdatetime.should.be.a(six.string_types)

        x = conn.describe_step(cluster_id, x.id)
        list(arg.value for arg in x.config.args).should.equal([
            '-mapper', y.mapper,
            '-reducer', y.reducer,
            '-input', y.input,
            '-output', y.output,
        ])
        x.config.jar.should.equal(
            '/home/hadoop/contrib/streaming/hadoop-streaming.jar')
        x.config.mainclass.should.equal('')
        # properties
        x.should.have.property('id').should.be.a(six.string_types)
        x.name.should.equal(y.name)
        x.status.state.should.be.within(['STARTING', 'PENDING'])
        # x.status.statechangereason
        x.status.timeline.creationdatetime.should.be.a(six.string_types)
        # x.status.timeline.enddatetime.should.be.a(six.string_types)
        # x.status.timeline.startdatetime.should.be.a(six.string_types)

    @requires_boto_gte('2.39')
    def test_list_steps_with_states():
        # boto's list_steps prior to 2.39 has a bug that ignores
        # step_states argument.
        steps = conn.list_steps(cluster_id).steps
        step_id = steps[0].id
        steps = conn.list_steps(cluster_id, step_states=['STARTING']).steps
        steps.should.have.length_of(1)
        steps[0].id.should.equal(step_id)
    test_list_steps_with_states()


@mock_emr_deprecated
def test_tags():
    input_tags = {"tag1": "val1", "tag2": "val2"}

    conn = boto.connect_emr()
    cluster_id = conn.run_jobflow(**run_jobflow_args)

    conn.add_tags(cluster_id, input_tags)
    cluster = conn.describe_cluster(cluster_id)
    cluster.tags.should.have.length_of(2)
    dict((t.key, t.value) for t in cluster.tags).should.equal(input_tags)

    conn.remove_tags(cluster_id, list(input_tags.keys()))
    cluster = conn.describe_cluster(cluster_id)
    cluster.tags.should.have.length_of(0)