diff --git a/.travis.yml b/.travis.yml
index 8d22aa98f..f1854db54 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -35,9 +35,10 @@ install:
   if [ "$TEST_SERVER_MODE" = "true" ]; then
     python wait_for.py
   fi
+before_script:
+- if [[ $TRAVIS_PYTHON_VERSION == "3.7" ]]; then make lint; fi
 script:
 - make test-only
-- if [[ $TRAVIS_PYTHON_VERSION == "3.7" ]]; then make lint; fi
 after_success:
 - coveralls
 before_deploy:
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8413c796d..732dad23a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -31,7 +31,6 @@ Moto Changelog
             * delete_configuration_aggregator()
             * describe_aggregation_authorizations()
             * describe_configuration_aggregators()
-            * describe_identity_pool()
             * get_resource_config_history()
             * list_aggregate_discovered_resources() (For S3)
             * list_discovered_resources() (For S3)
@@ -39,6 +38,7 @@ Moto Changelog
             * put_configuration_aggregator()
         * Cognito
             * assume_role_with_web_identity()
+            * describe_identity_pool()
             * get_open_id_token()
             * update_user_pool_domain()
         * DataSync:
diff --git a/IMPLEMENTATION_COVERAGE.md b/IMPLEMENTATION_COVERAGE.md
index 2e5f055b9..c026ef601 100644
--- a/IMPLEMENTATION_COVERAGE.md
+++ b/IMPLEMENTATION_COVERAGE.md
@@ -2718,12 +2718,12 @@
 - [ ] upgrade_elasticsearch_domain
 
 ## events
-48% implemented
+58% implemented
 - [ ] activate_event_source
-- [ ] create_event_bus
+- [X] create_event_bus
 - [ ] create_partner_event_source
 - [ ] deactivate_event_source
-- [ ] delete_event_bus
+- [X] delete_event_bus
 - [ ] delete_partner_event_source
 - [X] delete_rule
 - [X] describe_event_bus
@@ -2732,7 +2732,7 @@
 - [X] describe_rule
 - [X] disable_rule
 - [X] enable_rule
-- [ ] list_event_buses
+- [X] list_event_buses
 - [ ] list_event_sources
 - [ ] list_partner_event_source_accounts
 - [ ] list_partner_event_sources
@@ -3977,46 +3977,46 @@
 - [ ] update_resource
 
 ## lambda
-0% implemented
+41% implemented
 - [ ] add_layer_version_permission
 - [ ] add_permission
 - [ ] create_alias
-- [ ] create_event_source_mapping
-- [ ] create_function
+- [X] create_event_source_mapping
+- [X] create_function
 - [ ] delete_alias
-- [ ] delete_event_source_mapping
-- [ ] delete_function
+- [X] delete_event_source_mapping
+- [X] delete_function
 - [ ] delete_function_concurrency
 - [ ] delete_layer_version
 - [ ] get_account_settings
 - [ ] get_alias
-- [ ] get_event_source_mapping
-- [ ] get_function
+- [X] get_event_source_mapping
+- [X] get_function
 - [ ] get_function_configuration
 - [ ] get_layer_version
 - [ ] get_layer_version_by_arn
 - [ ] get_layer_version_policy
 - [ ] get_policy
-- [ ] invoke
+- [X] invoke
 - [ ] invoke_async
 - [ ] list_aliases
-- [ ] list_event_source_mappings
-- [ ] list_functions
+- [X] list_event_source_mappings
+- [X] list_functions
 - [ ] list_layer_versions
 - [ ] list_layers
-- [ ] list_tags
-- [ ] list_versions_by_function
+- [X] list_tags
+- [X] list_versions_by_function
 - [ ] publish_layer_version
 - [ ] publish_version
 - [ ] put_function_concurrency
 - [ ] remove_layer_version_permission
 - [ ] remove_permission
-- [ ] tag_resource
-- [ ] untag_resource
+- [X] tag_resource
+- [X] untag_resource
 - [ ] update_alias
-- [ ] update_event_source_mapping
-- [ ] update_function_code
-- [ ] update_function_configuration
+- [X] update_event_source_mapping
+- [X] update_function_code
+- [X] update_function_configuration
 
 ## lex-models
 0% implemented
@@ -4723,7 +4723,7 @@
 - [ ] update_server_engine_attributes
 
 ## organizations
-41% implemented
+43% implemented
 - [ ] accept_handshake
 - [X] attach_policy
 - [ ] cancel_handshake
@@ -4737,7 +4737,7 @@
 - [ ] delete_organizational_unit
 - [ ] delete_policy
 - [X] describe_account
-- [ ] describe_create_account_status
+- [X] describe_create_account_status
 - [ ] describe_handshake
 - [X] describe_organization
 - [X] describe_organizational_unit
diff --git a/moto/awslambda/models.py b/moto/awslambda/models.py
index a58582599..fe5c24c53 100644
--- a/moto/awslambda/models.py
+++ b/moto/awslambda/models.py
@@ -979,6 +979,32 @@ class LambdaBackend(BaseBackend):
     def add_policy(self, function_name, policy):
         self.get_function(function_name).policy = policy
 
+    def update_function_code(self, function_name, qualifier, body):
+        fn = self.get_function(function_name, qualifier)
+
+        if fn:
+            if body.get("Publish", False):
+                fn = self.publish_function(function_name)
+
+            config = fn.update_function_code(body)
+            return config
+        else:
+            return None
+
+    def update_function_configuration(self, function_name, qualifier, body):
+        fn = self.get_function(function_name, qualifier)
+
+        return fn.update_configuration(body) if fn else None
+
+    def invoke(self, function_name, qualifier, body, headers, response_headers):
+        fn = self.get_function(function_name, qualifier)
+        if fn:
+            payload = fn.invoke(body, headers, response_headers)
+            response_headers["Content-Length"] = str(len(payload))
+            return response_headers, payload
+        else:
+            return response_headers, None
+
 
 def do_validate_s3():
     return os.environ.get("VALIDATE_LAMBDA_S3", "") in ["", "1", "true"]
diff --git a/moto/awslambda/responses.py b/moto/awslambda/responses.py
index 62265b310..96a8afda6 100644
--- a/moto/awslambda/responses.py
+++ b/moto/awslambda/responses.py
@@ -168,10 +168,10 @@ class LambdaResponse(BaseResponse):
         function_name = self.path.rsplit("/", 2)[-2]
         qualifier = self._get_param("qualifier")
 
-        fn = self.lambda_backend.get_function(function_name, qualifier)
-        if fn:
-            payload = fn.invoke(self.body, self.headers, response_headers)
-            response_headers["Content-Length"] = str(len(payload))
+        response_header, payload = self.lambda_backend.invoke(
+            function_name, qualifier, self.body, self.headers, response_headers
+        )
+        if payload:
             return 202, response_headers, payload
         else:
             return 404, response_headers, "{}"
@@ -337,26 +337,23 @@ class LambdaResponse(BaseResponse):
     def _put_configuration(self, request):
         function_name = self.path.rsplit("/", 2)[-2]
         qualifier = self._get_param("Qualifier", None)
+        resp = self.lambda_backend.update_function_configuration(
+            function_name, qualifier, body=self.json_body
+        )
 
-        fn = self.lambda_backend.get_function(function_name, qualifier)
-
-        if fn:
-            config = fn.update_configuration(self.json_body)
-            return 200, {}, json.dumps(config)
+        if resp:
+            return 200, {}, json.dumps(resp)
         else:
             return 404, {}, "{}"
 
     def _put_code(self):
         function_name = self.path.rsplit("/", 2)[-2]
         qualifier = self._get_param("Qualifier", None)
+        resp = self.lambda_backend.update_function_code(
+            function_name, qualifier, body=self.json_body
+        )
 
-        fn = self.lambda_backend.get_function(function_name, qualifier)
-
-        if fn:
-            if self.json_body.get("Publish", False):
-                fn = self.lambda_backend.publish_function(function_name)
-
-            config = fn.update_function_code(self.json_body)
-            return 200, {}, json.dumps(config)
+        if resp:
+            return 200, {}, json.dumps(resp)
         else:
             return 404, {}, "{}"
diff --git a/moto/datasync/models.py b/moto/datasync/models.py
index 42626cceb..17a2659fb 100644
--- a/moto/datasync/models.py
+++ b/moto/datasync/models.py
@@ -27,12 +27,14 @@ class Task(BaseModel):
         name,
         region_name,
         arn_counter=0,
+        metadata=None,
     ):
         self.source_location_arn = source_location_arn
         self.destination_location_arn = destination_location_arn
+        self.name = name
+        self.metadata = metadata
         # For simplicity Tasks are either available or running
         self.status = "AVAILABLE"
-        self.name = name
         self.current_task_execution_arn = None
         # Generate ARN
         self.arn = "arn:aws:datasync:{0}:111222333444:task/task-{1}".format(
@@ -129,7 +131,27 @@ class DataSyncBackend(BaseBackend):
         self.locations[location.arn] = location
         return location.arn
 
-    def create_task(self, source_location_arn, destination_location_arn, name):
+    def _get_location(self, location_arn, typ):
+        if location_arn not in self.locations:
+            raise InvalidRequestException(
+                "Location {0} is not found.".format(location_arn)
+            )
+        location = self.locations[location_arn]
+        if location.typ != typ:
+            raise InvalidRequestException(
+                "Invalid Location type: {0}".format(location.typ)
+            )
+        return location
+
+    def delete_location(self, location_arn):
+        if location_arn in self.locations:
+            del self.locations[location_arn]
+        else:
+            raise InvalidRequestException
+
+    def create_task(
+        self, source_location_arn, destination_location_arn, name, metadata=None
+    ):
         if source_location_arn not in self.locations:
             raise InvalidRequestException(
                 "Location {0} not found.".format(source_location_arn)
@@ -145,10 +167,33 @@ class DataSyncBackend(BaseBackend):
             name,
             region_name=self.region_name,
             arn_counter=self.arn_counter,
+            metadata=metadata,
         )
         self.tasks[task.arn] = task
         return task.arn
 
+    def _get_task(self, task_arn):
+        if task_arn in self.tasks:
+            return self.tasks[task_arn]
+        else:
+            raise InvalidRequestException
+
+    def update_task(self, task_arn, name, metadata):
+        if task_arn in self.tasks:
+            task = self.tasks[task_arn]
+            task.name = name
+            task.metadata = metadata
+        else:
+            raise InvalidRequestException(
+                "Sync task {0} is not found.".format(task_arn)
+            )
+
+    def delete_task(self, task_arn):
+        if task_arn in self.tasks:
+            del self.tasks[task_arn]
+        else:
+            raise InvalidRequestException
+
     def start_task_execution(self, task_arn):
         self.arn_counter = self.arn_counter + 1
         if task_arn in self.tasks:
@@ -161,12 +206,19 @@ class DataSyncBackend(BaseBackend):
                 return task_execution.arn
         raise InvalidRequestException("Invalid request.")
 
+    def _get_task_execution(self, task_execution_arn):
+        if task_execution_arn in self.task_executions:
+            return self.task_executions[task_execution_arn]
+        else:
+            raise InvalidRequestException
+
     def cancel_task_execution(self, task_execution_arn):
         if task_execution_arn in self.task_executions:
             task_execution = self.task_executions[task_execution_arn]
             task_execution.cancel()
             task_arn = task_execution.task_arn
             self.tasks[task_arn].current_task_execution_arn = None
+            self.tasks[task_arn].status = "AVAILABLE"
             return
         raise InvalidRequestException(
             "Sync task {0} is not found.".format(task_execution_arn)
diff --git a/moto/datasync/responses.py b/moto/datasync/responses.py
index 30b906d44..23a480523 100644
--- a/moto/datasync/responses.py
+++ b/moto/datasync/responses.py
@@ -2,7 +2,6 @@ import json
 
 from moto.core.responses import BaseResponse
 
-from .exceptions import InvalidRequestException
 from .models import datasync_backends
 
 
@@ -18,17 +17,7 @@ class DataSyncResponse(BaseResponse):
         return json.dumps({"Locations": locations})
 
     def _get_location(self, location_arn, typ):
-        location_arn = self._get_param("LocationArn")
-        if location_arn not in self.datasync_backend.locations:
-            raise InvalidRequestException(
-                "Location {0} is not found.".format(location_arn)
-            )
-        location = self.datasync_backend.locations[location_arn]
-        if location.typ != typ:
-            raise InvalidRequestException(
-                "Invalid Location type: {0}".format(location.typ)
-            )
-        return location
+        return self.datasync_backend._get_location(location_arn, typ)
 
     def create_location_s3(self):
         # s3://bucket_name/folder/
@@ -86,16 +75,40 @@ class DataSyncResponse(BaseResponse):
             }
         )
 
+    def delete_location(self):
+        location_arn = self._get_param("LocationArn")
+        self.datasync_backend.delete_location(location_arn)
+        return json.dumps({})
+
     def create_task(self):
         destination_location_arn = self._get_param("DestinationLocationArn")
         source_location_arn = self._get_param("SourceLocationArn")
         name = self._get_param("Name")
-
+        metadata = {
+            "CloudWatchLogGroupArn": self._get_param("CloudWatchLogGroupArn"),
+            "Options": self._get_param("Options"),
+            "Excludes": self._get_param("Excludes"),
+            "Tags": self._get_param("Tags"),
+        }
         arn = self.datasync_backend.create_task(
-            source_location_arn, destination_location_arn, name
+            source_location_arn, destination_location_arn, name, metadata=metadata
         )
         return json.dumps({"TaskArn": arn})
 
+    def update_task(self):
+        task_arn = self._get_param("TaskArn")
+        self.datasync_backend.update_task(
+            task_arn,
+            name=self._get_param("Name"),
+            metadata={
+                "CloudWatchLogGroupArn": self._get_param("CloudWatchLogGroupArn"),
+                "Options": self._get_param("Options"),
+                "Excludes": self._get_param("Excludes"),
+                "Tags": self._get_param("Tags"),
+            },
+        )
+        return json.dumps({})
+
     def list_tasks(self):
         tasks = list()
         for arn, task in self.datasync_backend.tasks.items():
@@ -104,29 +117,32 @@ class DataSyncResponse(BaseResponse):
             )
         return json.dumps({"Tasks": tasks})
 
+    def delete_task(self):
+        task_arn = self._get_param("TaskArn")
+        self.datasync_backend.delete_task(task_arn)
+        return json.dumps({})
+
     def describe_task(self):
         task_arn = self._get_param("TaskArn")
-        if task_arn in self.datasync_backend.tasks:
-            task = self.datasync_backend.tasks[task_arn]
-            return json.dumps(
-                {
-                    "TaskArn": task.arn,
-                    "Name": task.name,
-                    "CurrentTaskExecutionArn": task.current_task_execution_arn,
-                    "Status": task.status,
-                    "SourceLocationArn": task.source_location_arn,
-                    "DestinationLocationArn": task.destination_location_arn,
-                }
-            )
-        raise InvalidRequestException
+        task = self.datasync_backend._get_task(task_arn)
+        return json.dumps(
+            {
+                "TaskArn": task.arn,
+                "Status": task.status,
+                "Name": task.name,
+                "CurrentTaskExecutionArn": task.current_task_execution_arn,
+                "SourceLocationArn": task.source_location_arn,
+                "DestinationLocationArn": task.destination_location_arn,
+                "CloudWatchLogGroupArn": task.metadata["CloudWatchLogGroupArn"],
+                "Options": task.metadata["Options"],
+                "Excludes": task.metadata["Excludes"],
+            }
+        )
 
     def start_task_execution(self):
         task_arn = self._get_param("TaskArn")
-        if task_arn in self.datasync_backend.tasks:
-            arn = self.datasync_backend.start_task_execution(task_arn)
-            if arn:
-                return json.dumps({"TaskExecutionArn": arn})
-        raise InvalidRequestException("Invalid request.")
+        arn = self.datasync_backend.start_task_execution(task_arn)
+        return json.dumps({"TaskExecutionArn": arn})
 
     def cancel_task_execution(self):
         task_execution_arn = self._get_param("TaskExecutionArn")
@@ -135,21 +151,12 @@ class DataSyncResponse(BaseResponse):
 
     def describe_task_execution(self):
         task_execution_arn = self._get_param("TaskExecutionArn")
-
-        if task_execution_arn in self.datasync_backend.task_executions:
-            task_execution = self.datasync_backend.task_executions[task_execution_arn]
-            if task_execution:
-                result = json.dumps(
-                    {
-                        "TaskExecutionArn": task_execution.arn,
-                        "Status": task_execution.status,
-                    }
-                )
-                if task_execution.status == "SUCCESS":
-                    self.datasync_backend.tasks[
-                        task_execution.task_arn
-                    ].status = "AVAILABLE"
-                # Simulate task being executed
-                task_execution.iterate_status()
-                return result
-        raise InvalidRequestException
+        task_execution = self.datasync_backend._get_task_execution(task_execution_arn)
+        result = json.dumps(
+            {"TaskExecutionArn": task_execution.arn, "Status": task_execution.status,}
+        )
+        if task_execution.status == "SUCCESS":
+            self.datasync_backend.tasks[task_execution.task_arn].status = "AVAILABLE"
+        # Simulate task being executed
+        task_execution.iterate_status()
+        return result
diff --git a/moto/dynamodb2/models.py b/moto/dynamodb2/models.py
index 8a061041e..6361f8961 100644
--- a/moto/dynamodb2/models.py
+++ b/moto/dynamodb2/models.py
@@ -77,6 +77,7 @@ class DynamoType(object):
             attr, list_index = attribute_is_list(attr)
             if not key:
                 # {'S': value} ==> {'S': new_value}
+                self.type = new_value.type
                 self.value = new_value.value
             else:
                 if attr not in self.value:  # nonexistingattribute
diff --git a/moto/ec2/models.py b/moto/ec2/models.py
index efbbeb6fe..ccc7c7a37 100644
--- a/moto/ec2/models.py
+++ b/moto/ec2/models.py
@@ -214,6 +214,7 @@ class NetworkInterface(TaggedEC2Resource):
         ec2_backend,
         subnet,
         private_ip_address,
+        private_ip_addresses=None,
         device_index=0,
         public_ip_auto_assign=True,
         group_ids=None,
@@ -223,6 +224,7 @@ class NetworkInterface(TaggedEC2Resource):
         self.id = random_eni_id()
         self.device_index = device_index
         self.private_ip_address = private_ip_address or random_private_ip()
+        self.private_ip_addresses = private_ip_addresses
         self.subnet = subnet
         self.instance = None
         self.attachment_id = None
@@ -341,12 +343,19 @@ class NetworkInterfaceBackend(object):
         super(NetworkInterfaceBackend, self).__init__()
 
     def create_network_interface(
-        self, subnet, private_ip_address, group_ids=None, description=None, **kwargs
+        self,
+        subnet,
+        private_ip_address,
+        private_ip_addresses=None,
+        group_ids=None,
+        description=None,
+        **kwargs
     ):
         eni = NetworkInterface(
             self,
             subnet,
             private_ip_address,
+            private_ip_addresses,
             group_ids=group_ids,
             description=description,
             **kwargs
@@ -2819,6 +2828,9 @@ class Subnet(TaggedEC2Resource):
         self.vpc_id = vpc_id
         self.cidr_block = cidr_block
         self.cidr = ipaddress.IPv4Network(six.text_type(self.cidr_block), strict=False)
+        self._available_ip_addresses = (
+            ipaddress.IPv4Network(six.text_type(self.cidr_block)).num_addresses - 5
+        )
         self._availability_zone = availability_zone
         self.default_for_az = default_for_az
         self.map_public_ip_on_launch = map_public_ip_on_launch
@@ -2854,6 +2866,21 @@ class Subnet(TaggedEC2Resource):
 
         return subnet
 
+    @property
+    def available_ip_addresses(self):
+        enis = [
+            eni
+            for eni in self.ec2_backend.get_all_network_interfaces()
+            if eni.subnet.id == self.id
+        ]
+        addresses_taken = [
+            eni.private_ip_address for eni in enis if eni.private_ip_address
+        ]
+        for eni in enis:
+            if eni.private_ip_addresses:
+                addresses_taken.extend(eni.private_ip_addresses)
+        return str(self._available_ip_addresses - len(addresses_taken))
+
     @property
     def availability_zone(self):
         return self._availability_zone.name
diff --git a/moto/ec2/responses/elastic_network_interfaces.py b/moto/ec2/responses/elastic_network_interfaces.py
index fa014b219..6761b294e 100644
--- a/moto/ec2/responses/elastic_network_interfaces.py
+++ b/moto/ec2/responses/elastic_network_interfaces.py
@@ -7,12 +7,13 @@ class ElasticNetworkInterfaces(BaseResponse):
     def create_network_interface(self):
         subnet_id = self._get_param("SubnetId")
         private_ip_address = self._get_param("PrivateIpAddress")
+        private_ip_addresses = self._get_multi_param("PrivateIpAddresses")
         groups = self._get_multi_param("SecurityGroupId")
         subnet = self.ec2_backend.get_subnet(subnet_id)
         description = self._get_param("Description")
         if self.is_not_dryrun("CreateNetworkInterface"):
             eni = self.ec2_backend.create_network_interface(
-                subnet, private_ip_address, groups, description
+                subnet, private_ip_address, private_ip_addresses, groups, description
             )
             template = self.response_template(CREATE_NETWORK_INTERFACE_RESPONSE)
             return template.render(eni=eni)
diff --git a/moto/ec2/responses/subnets.py b/moto/ec2/responses/subnets.py
index c42583f23..e11984e52 100644
--- a/moto/ec2/responses/subnets.py
+++ b/moto/ec2/responses/subnets.py
@@ -53,7 +53,7 @@ CREATE_SUBNET_RESPONSE = """
     <state>pending</state>
     <vpcId>{{ subnet.vpc_id }}</vpcId>
     <cidrBlock>{{ subnet.cidr_block }}</cidrBlock>
-    <availableIpAddressCount>251</availableIpAddressCount>
+    <availableIpAddressCount>{{ subnet.available_ip_addresses }}</availableIpAddressCount>
     <availabilityZone>{{ subnet._availability_zone.name }}</availabilityZone>
     <availabilityZoneId>{{ subnet._availability_zone.zone_id }}</availabilityZoneId>
     <defaultForAz>{{ subnet.default_for_az }}</defaultForAz>
@@ -81,7 +81,7 @@ DESCRIBE_SUBNETS_RESPONSE = """
         <state>available</state>
         <vpcId>{{ subnet.vpc_id }}</vpcId>
         <cidrBlock>{{ subnet.cidr_block }}</cidrBlock>
-        <availableIpAddressCount>251</availableIpAddressCount>
+        <availableIpAddressCount>{{ subnet.available_ip_addresses }}</availableIpAddressCount>
         <availabilityZone>{{ subnet._availability_zone.name }}</availabilityZone>
         <availabilityZoneId>{{ subnet._availability_zone.zone_id }}</availabilityZoneId>
         <defaultForAz>{{ subnet.default_for_az }}</defaultForAz>
diff --git a/moto/events/models.py b/moto/events/models.py
index e69062b2c..be4153b9f 100644
--- a/moto/events/models.py
+++ b/moto/events/models.py
@@ -5,6 +5,7 @@ import boto3
 
 from moto.core.exceptions import JsonRESTError
 from moto.core import BaseBackend, BaseModel
+from moto.sts.models import ACCOUNT_ID
 
 
 class Rule(BaseModel):
@@ -54,6 +55,42 @@ class Rule(BaseModel):
                 self.targets.pop(index)
 
 
+class EventBus(BaseModel):
+    def __init__(self, region_name, name):
+        self.region = region_name
+        self.name = name
+
+        self._permissions = {}
+
+    @property
+    def arn(self):
+        return "arn:aws:events:{region}:{account_id}:event-bus/{name}".format(
+            region=self.region, account_id=ACCOUNT_ID, name=self.name
+        )
+
+    @property
+    def policy(self):
+        if not len(self._permissions):
+            return None
+
+        policy = {"Version": "2012-10-17", "Statement": []}
+
+        for sid, permission in self._permissions.items():
+            policy["Statement"].append(
+                {
+                    "Sid": sid,
+                    "Effect": "Allow",
+                    "Principal": {
+                        "AWS": "arn:aws:iam::{}:root".format(permission["Principal"])
+                    },
+                    "Action": permission["Action"],
+                    "Resource": self.arn,
+                }
+            )
+
+        return json.dumps(policy)
+
+
 class EventsBackend(BaseBackend):
     ACCOUNT_ID = re.compile(r"^(\d{1,12}|\*)$")
     STATEMENT_ID = re.compile(r"^[a-zA-Z0-9-_]{1,64}$")
@@ -65,13 +102,19 @@ class EventsBackend(BaseBackend):
         self.rules_order = []
         self.next_tokens = {}
         self.region_name = region_name
-        self.permissions = {}
+        self.event_buses = {}
+        self.event_sources = {}
+
+        self._add_default_event_bus()
 
     def reset(self):
         region_name = self.region_name
         self.__dict__ = {}
         self.__init__(region_name)
 
+    def _add_default_event_bus(self):
+        self.event_buses["default"] = EventBus(self.region_name, "default")
+
     def _get_rule_by_index(self, i):
         return self.rules.get(self.rules_order[i])
 
@@ -221,9 +264,17 @@ class EventsBackend(BaseBackend):
     def test_event_pattern(self):
         raise NotImplementedError()
 
-    def put_permission(self, action, principal, statement_id):
+    def put_permission(self, event_bus_name, action, principal, statement_id):
+        if not event_bus_name:
+            event_bus_name = "default"
+
+        event_bus = self.describe_event_bus(event_bus_name)
+
         if action is None or action != "events:PutEvents":
-            raise JsonRESTError("InvalidParameterValue", "Action must be PutEvents")
+            raise JsonRESTError(
+                "ValidationException",
+                "Provided value in parameter 'action' is not supported.",
+            )
 
         if principal is None or self.ACCOUNT_ID.match(principal) is None:
             raise JsonRESTError(
@@ -235,34 +286,81 @@ class EventsBackend(BaseBackend):
                 "InvalidParameterValue", "StatementId must match ^[a-zA-Z0-9-_]{1,64}$"
             )
 
-        self.permissions[statement_id] = {"action": action, "principal": principal}
+        event_bus._permissions[statement_id] = {
+            "Action": action,
+            "Principal": principal,
+        }
 
-    def remove_permission(self, statement_id):
-        try:
-            del self.permissions[statement_id]
-        except KeyError:
-            raise JsonRESTError("ResourceNotFoundException", "StatementId not found")
+    def remove_permission(self, event_bus_name, statement_id):
+        if not event_bus_name:
+            event_bus_name = "default"
 
-    def describe_event_bus(self):
-        arn = "arn:aws:events:{0}:000000000000:event-bus/default".format(
-            self.region_name
-        )
-        statements = []
-        for statement_id, data in self.permissions.items():
-            statements.append(
-                {
-                    "Sid": statement_id,
-                    "Effect": "Allow",
-                    "Principal": {
-                        "AWS": "arn:aws:iam::{0}:root".format(data["principal"])
-                    },
-                    "Action": data["action"],
-                    "Resource": arn,
-                }
+        event_bus = self.describe_event_bus(event_bus_name)
+
+        if not len(event_bus._permissions):
+            raise JsonRESTError(
+                "ResourceNotFoundException", "EventBus does not have a policy."
             )
-        policy = {"Version": "2012-10-17", "Statement": statements}
-        policy_json = json.dumps(policy)
-        return {"Policy": policy_json, "Name": "default", "Arn": arn}
+
+        if not event_bus._permissions.pop(statement_id, None):
+            raise JsonRESTError(
+                "ResourceNotFoundException",
+                "Statement with the provided id does not exist.",
+            )
+
+    def describe_event_bus(self, name):
+        if not name:
+            name = "default"
+
+        event_bus = self.event_buses.get(name)
+
+        if not event_bus:
+            raise JsonRESTError(
+                "ResourceNotFoundException",
+                "Event bus {} does not exist.".format(name),
+            )
+
+        return event_bus
+
+    def create_event_bus(self, name, event_source_name):
+        if name in self.event_buses:
+            raise JsonRESTError(
+                "ResourceAlreadyExistsException",
+                "Event bus {} already exists.".format(name),
+            )
+
+        if not event_source_name and "/" in name:
+            raise JsonRESTError(
+                "ValidationException", "Event bus name must not contain '/'."
+            )
+
+        if event_source_name and event_source_name not in self.event_sources:
+            raise JsonRESTError(
+                "ResourceNotFoundException",
+                "Event source {} does not exist.".format(event_source_name),
+            )
+
+        self.event_buses[name] = EventBus(self.region_name, name)
+
+        return self.event_buses[name]
+
+    def list_event_buses(self, name_prefix):
+        if name_prefix:
+            return [
+                event_bus
+                for event_bus in self.event_buses.values()
+                if event_bus.name.startswith(name_prefix)
+            ]
+
+        return list(self.event_buses.values())
+
+    def delete_event_bus(self, name):
+        if name == "default":
+            raise JsonRESTError(
+                "ValidationException", "Cannot delete event bus default."
+            )
+
+        self.event_buses.pop(name, None)
 
 
 available_regions = boto3.session.Session().get_available_regions("events")
diff --git a/moto/events/responses.py b/moto/events/responses.py
index 39c5c75dc..98a33218a 100644
--- a/moto/events/responses.py
+++ b/moto/events/responses.py
@@ -238,20 +238,68 @@ class EventsHandler(BaseResponse):
         pass
 
     def put_permission(self):
+        event_bus_name = self._get_param("EventBusName")
         action = self._get_param("Action")
         principal = self._get_param("Principal")
         statement_id = self._get_param("StatementId")
 
-        self.events_backend.put_permission(action, principal, statement_id)
+        self.events_backend.put_permission(
+            event_bus_name, action, principal, statement_id
+        )
 
         return ""
 
     def remove_permission(self):
+        event_bus_name = self._get_param("EventBusName")
         statement_id = self._get_param("StatementId")
 
-        self.events_backend.remove_permission(statement_id)
+        self.events_backend.remove_permission(event_bus_name, statement_id)
 
         return ""
 
     def describe_event_bus(self):
-        return json.dumps(self.events_backend.describe_event_bus())
+        name = self._get_param("Name")
+
+        event_bus = self.events_backend.describe_event_bus(name)
+        response = {
+            "Name": event_bus.name,
+            "Arn": event_bus.arn,
+        }
+
+        if event_bus.policy:
+            response["Policy"] = event_bus.policy
+
+        return json.dumps(response), self.response_headers
+
+    def create_event_bus(self):
+        name = self._get_param("Name")
+        event_source_name = self._get_param("EventSourceName")
+
+        event_bus = self.events_backend.create_event_bus(name, event_source_name)
+
+        return json.dumps({"EventBusArn": event_bus.arn}), self.response_headers
+
+    def list_event_buses(self):
+        name_prefix = self._get_param("NamePrefix")
+        # ToDo: add 'NextToken' & 'Limit' parameters
+
+        response = []
+        for event_bus in self.events_backend.list_event_buses(name_prefix):
+            event_bus_response = {
+                "Name": event_bus.name,
+                "Arn": event_bus.arn,
+            }
+
+            if event_bus.policy:
+                event_bus_response["Policy"] = event_bus.policy
+
+            response.append(event_bus_response)
+
+        return json.dumps({"EventBuses": response}), self.response_headers
+
+    def delete_event_bus(self):
+        name = self._get_param("Name")
+
+        self.events_backend.delete_event_bus(name)
+
+        return "", self.response_headers
diff --git a/moto/iam/models.py b/moto/iam/models.py
index 1110da682..b64c9402f 100644
--- a/moto/iam/models.py
+++ b/moto/iam/models.py
@@ -818,6 +818,12 @@ class IAMBackend(BaseBackend):
         policy = ManagedPolicy(
             policy_name, description=description, document=policy_document, path=path
         )
+        if policy.arn in self.managed_policies:
+            raise EntityAlreadyExists(
+                "A policy called {} already exists. Duplicate names are not allowed.".format(
+                    policy_name
+                )
+            )
         self.managed_policies[policy.arn] = policy
         return policy
 
@@ -1227,6 +1233,14 @@ class IAMBackend(BaseBackend):
         group = self.get_group(group_name)
         return group.get_policy(policy_name)
 
+    def delete_group(self, group_name):
+        try:
+            del self.groups[group_name]
+        except KeyError:
+            raise IAMNotFoundException(
+                "The group with name {0} cannot be found.".format(group_name)
+            )
+
     def create_user(self, user_name, path="/"):
         if user_name in self.users:
             raise IAMConflictException(
diff --git a/moto/iam/responses.py b/moto/iam/responses.py
index 08fe13dc5..4bd1aa80c 100644
--- a/moto/iam/responses.py
+++ b/moto/iam/responses.py
@@ -428,6 +428,12 @@ class IamResponse(BaseResponse):
         template = self.response_template(GET_GROUP_POLICY_TEMPLATE)
         return template.render(name="GetGroupPolicyResponse", **policy_result)
 
+    def delete_group(self):
+        group_name = self._get_param("GroupName")
+        iam_backend.delete_group(group_name)
+        template = self.response_template(GENERIC_EMPTY_TEMPLATE)
+        return template.render(name="DeleteGroup")
+
     def create_user(self):
         user_name = self._get_param("UserName")
         path = self._get_param("Path")
diff --git a/moto/organizations/models.py b/moto/organizations/models.py
index 37f8bdeb9..d558616d2 100644
--- a/moto/organizations/models.py
+++ b/moto/organizations/models.py
@@ -269,10 +269,32 @@ class OrganizationsBackend(BaseBackend):
             )
         return account
 
+    def get_account_by_attr(self, attr, value):
+        account = next(
+            (
+                account
+                for account in self.accounts
+                if hasattr(account, attr) and getattr(account, attr) == value
+            ),
+            None,
+        )
+        if account is None:
+            raise RESTError(
+                "AccountNotFoundException",
+                "You specified an account that doesn't exist.",
+            )
+        return account
+
     def describe_account(self, **kwargs):
         account = self.get_account_by_id(kwargs["AccountId"])
         return account.describe()
 
+    def describe_create_account_status(self, **kwargs):
+        account = self.get_account_by_attr(
+            "create_account_status_id", kwargs["CreateAccountRequestId"]
+        )
+        return account.create_account_status
+
     def list_accounts(self):
         return dict(
             Accounts=[account.describe()["Account"] for account in self.accounts]
diff --git a/moto/organizations/responses.py b/moto/organizations/responses.py
index 673bf5adb..f9e0b2e04 100644
--- a/moto/organizations/responses.py
+++ b/moto/organizations/responses.py
@@ -65,6 +65,13 @@ class OrganizationsResponse(BaseResponse):
             self.organizations_backend.describe_account(**self.request_params)
         )
 
+    def describe_create_account_status(self):
+        return json.dumps(
+            self.organizations_backend.describe_create_account_status(
+                **self.request_params
+            )
+        )
+
     def list_accounts(self):
         return json.dumps(self.organizations_backend.list_accounts())
 
diff --git a/moto/secretsmanager/exceptions.py b/moto/secretsmanager/exceptions.py
index 13f1f2766..bf717e20c 100644
--- a/moto/secretsmanager/exceptions.py
+++ b/moto/secretsmanager/exceptions.py
@@ -14,23 +14,21 @@ class ResourceNotFoundException(SecretsManagerClientError):
         )
 
 
-# Using specialised exception due to the use of a non-ASCII character
 class SecretNotFoundException(SecretsManagerClientError):
     def __init__(self):
         self.code = 404
         super(SecretNotFoundException, self).__init__(
             "ResourceNotFoundException",
-            message="Secrets Manager can\u2019t find the specified secret.",
+            message="Secrets Manager can't find the specified secret.",
         )
 
 
-# Using specialised exception due to the use of a non-ASCII character
 class SecretHasNoValueException(SecretsManagerClientError):
     def __init__(self, version_stage):
         self.code = 404
         super(SecretHasNoValueException, self).__init__(
             "ResourceNotFoundException",
-            message="Secrets Manager can\u2019t find the specified secret "
+            message="Secrets Manager can't find the specified secret "
             "value for staging label: {}".format(version_stage),
         )
 
diff --git a/scripts/implementation_coverage.py b/scripts/implementation_coverage.py
index b3855e0b2..4552ec18e 100755
--- a/scripts/implementation_coverage.py
+++ b/scripts/implementation_coverage.py
@@ -7,16 +7,18 @@ import boto3
 
 
 script_dir = os.path.dirname(os.path.abspath(__file__))
+alternative_service_names = {'lambda': 'awslambda'}
 
 
 def get_moto_implementation(service_name):
-    service_name_standardized = service_name.replace("-", "") if "-" in service_name else service_name
-    if not hasattr(moto, service_name_standardized):
+    service_name = service_name.replace("-", "") if "-" in service_name else service_name
+    alt_service_name = alternative_service_names[service_name] if service_name in alternative_service_names else service_name
+    if not hasattr(moto, alt_service_name):
         return None
-    module = getattr(moto, service_name_standardized)
+    module = getattr(moto, alt_service_name)
     if module is None:
         return None
-    mock = getattr(module, "mock_{}".format(service_name_standardized))
+    mock = getattr(module, "mock_{}".format(service_name))
     if mock is None:
         return None
     backends = list(mock().backends.values())
diff --git a/tests/test_core/test_auth.py b/tests/test_core/test_auth.py
index 7dc632188..c5e043ae5 100644
--- a/tests/test_core/test_auth.py
+++ b/tests/test_core/test_auth.py
@@ -402,10 +402,10 @@ def test_s3_access_denied_with_denying_attached_group_policy():
         "Statement": [{"Effect": "Deny", "Action": "s3:List*", "Resource": "*"}],
     }
     access_key = create_user_with_access_key_and_attached_policy(
-        user_name, attached_policy_document
+        user_name, attached_policy_document, policy_name="policy1"
     )
     create_group_with_attached_policy_and_add_user(
-        user_name, group_attached_policy_document
+        user_name, group_attached_policy_document, policy_name="policy2"
     )
     client = boto3.client(
         "s3",
@@ -476,10 +476,16 @@ def test_access_denied_with_many_irrelevant_policies():
         "Statement": [{"Effect": "Deny", "Action": "lambda:*", "Resource": "*"}],
     }
     access_key = create_user_with_access_key_and_multiple_policies(
-        user_name, inline_policy_document, attached_policy_document
+        user_name,
+        inline_policy_document,
+        attached_policy_document,
+        attached_policy_name="policy1",
     )
     create_group_with_multiple_policies_and_add_user(
-        user_name, group_inline_policy_document, group_attached_policy_document
+        user_name,
+        group_inline_policy_document,
+        group_attached_policy_document,
+        attached_policy_name="policy2",
     )
     client = boto3.client(
         "ec2",
diff --git a/tests/test_datasync/test_datasync.py b/tests/test_datasync/test_datasync.py
index 825eb7fba..e3ea87675 100644
--- a/tests/test_datasync/test_datasync.py
+++ b/tests/test_datasync/test_datasync.py
@@ -127,6 +127,22 @@ def test_list_locations():
     assert response["Locations"][2]["LocationUri"] == "s3://my_bucket/dir"
 
 
+@mock_datasync
+def test_delete_location():
+    client = boto3.client("datasync", region_name="us-east-1")
+    locations = create_locations(client, create_smb=True)
+    response = client.list_locations()
+    assert len(response["Locations"]) == 1
+    location_arn = locations["smb_arn"]
+
+    response = client.delete_location(LocationArn=location_arn)
+    response = client.list_locations()
+    assert len(response["Locations"]) == 0
+
+    with assert_raises(ClientError) as e:
+        response = client.delete_location(LocationArn=location_arn)
+
+
 @mock_datasync
 def test_create_task():
     client = boto3.client("datasync", region_name="us-east-1")
@@ -208,6 +224,72 @@ def test_describe_task_not_exist():
         client.describe_task(TaskArn="abc")
 
 
+@mock_datasync
+def test_update_task():
+    client = boto3.client("datasync", region_name="us-east-1")
+    locations = create_locations(client, create_s3=True, create_smb=True)
+
+    initial_name = "Initial_Name"
+    updated_name = "Updated_Name"
+    initial_options = {
+        "VerifyMode": "NONE",
+        "Atime": "BEST_EFFORT",
+        "Mtime": "PRESERVE",
+    }
+    updated_options = {
+        "VerifyMode": "POINT_IN_TIME_CONSISTENT",
+        "Atime": "BEST_EFFORT",
+        "Mtime": "PRESERVE",
+    }
+    response = client.create_task(
+        SourceLocationArn=locations["smb_arn"],
+        DestinationLocationArn=locations["s3_arn"],
+        Name=initial_name,
+        Options=initial_options,
+    )
+    task_arn = response["TaskArn"]
+    response = client.describe_task(TaskArn=task_arn)
+    assert response["TaskArn"] == task_arn
+    assert response["Name"] == initial_name
+    assert response["Options"] == initial_options
+
+    response = client.update_task(
+        TaskArn=task_arn, Name=updated_name, Options=updated_options
+    )
+
+    response = client.describe_task(TaskArn=task_arn)
+    assert response["TaskArn"] == task_arn
+    assert response["Name"] == updated_name
+    assert response["Options"] == updated_options
+
+    with assert_raises(ClientError) as e:
+        client.update_task(TaskArn="doesnt_exist")
+
+
+@mock_datasync
+def test_delete_task():
+    client = boto3.client("datasync", region_name="us-east-1")
+    locations = create_locations(client, create_s3=True, create_smb=True)
+
+    response = client.create_task(
+        SourceLocationArn=locations["smb_arn"],
+        DestinationLocationArn=locations["s3_arn"],
+        Name="task_name",
+    )
+
+    response = client.list_tasks()
+    assert len(response["Tasks"]) == 1
+    task_arn = response["Tasks"][0]["TaskArn"]
+    assert task_arn is not None
+
+    response = client.delete_task(TaskArn=task_arn)
+    response = client.list_tasks()
+    assert len(response["Tasks"]) == 0
+
+    with assert_raises(ClientError) as e:
+        response = client.delete_task(TaskArn=task_arn)
+
+
 @mock_datasync
 def test_start_task_execution():
     client = boto3.client("datasync", region_name="us-east-1")
@@ -261,6 +343,8 @@ def test_describe_task_execution():
         Name="task_name",
     )
     task_arn = response["TaskArn"]
+    response = client.describe_task(TaskArn=task_arn)
+    assert response["Status"] == "AVAILABLE"
 
     response = client.start_task_execution(TaskArn=task_arn)
     task_execution_arn = response["TaskExecutionArn"]
@@ -270,26 +354,38 @@ def test_describe_task_execution():
     response = client.describe_task_execution(TaskExecutionArn=task_execution_arn)
     assert response["TaskExecutionArn"] == task_execution_arn
     assert response["Status"] == "INITIALIZING"
+    response = client.describe_task(TaskArn=task_arn)
+    assert response["Status"] == "RUNNING"
 
     response = client.describe_task_execution(TaskExecutionArn=task_execution_arn)
     assert response["TaskExecutionArn"] == task_execution_arn
     assert response["Status"] == "PREPARING"
+    response = client.describe_task(TaskArn=task_arn)
+    assert response["Status"] == "RUNNING"
 
     response = client.describe_task_execution(TaskExecutionArn=task_execution_arn)
     assert response["TaskExecutionArn"] == task_execution_arn
     assert response["Status"] == "TRANSFERRING"
+    response = client.describe_task(TaskArn=task_arn)
+    assert response["Status"] == "RUNNING"
 
     response = client.describe_task_execution(TaskExecutionArn=task_execution_arn)
     assert response["TaskExecutionArn"] == task_execution_arn
     assert response["Status"] == "VERIFYING"
+    response = client.describe_task(TaskArn=task_arn)
+    assert response["Status"] == "RUNNING"
 
     response = client.describe_task_execution(TaskExecutionArn=task_execution_arn)
     assert response["TaskExecutionArn"] == task_execution_arn
     assert response["Status"] == "SUCCESS"
+    response = client.describe_task(TaskArn=task_arn)
+    assert response["Status"] == "AVAILABLE"
 
     response = client.describe_task_execution(TaskExecutionArn=task_execution_arn)
     assert response["TaskExecutionArn"] == task_execution_arn
     assert response["Status"] == "SUCCESS"
+    response = client.describe_task(TaskArn=task_arn)
+    assert response["Status"] == "AVAILABLE"
 
 
 @mock_datasync
@@ -317,11 +413,13 @@ def test_cancel_task_execution():
 
     response = client.describe_task(TaskArn=task_arn)
     assert response["CurrentTaskExecutionArn"] == task_execution_arn
+    assert response["Status"] == "RUNNING"
 
     response = client.cancel_task_execution(TaskExecutionArn=task_execution_arn)
 
     response = client.describe_task(TaskArn=task_arn)
     assert "CurrentTaskExecutionArn" not in response
+    assert response["Status"] == "AVAILABLE"
 
     response = client.describe_task_execution(TaskExecutionArn=task_execution_arn)
     assert response["Status"] == "ERROR"
diff --git a/tests/test_dynamodb2/test_dynamodb.py b/tests/test_dynamodb2/test_dynamodb.py
index d492b0135..7f6963870 100644
--- a/tests/test_dynamodb2/test_dynamodb.py
+++ b/tests/test_dynamodb2/test_dynamodb.py
@@ -3319,3 +3319,66 @@ def _create_user_table():
         TableName="users", Item={"username": {"S": "user3"}, "foo": {"S": "bar"}}
     )
     return client
+
+
+@mock_dynamodb2
+def test_update_item_if_original_value_is_none():
+    dynamo = boto3.resource("dynamodb", region_name="eu-central-1")
+    dynamo.create_table(
+        AttributeDefinitions=[{"AttributeName": "job_id", "AttributeType": "S"}],
+        TableName="origin-rbu-dev",
+        KeySchema=[{"AttributeName": "job_id", "KeyType": "HASH"}],
+        ProvisionedThroughput={"ReadCapacityUnits": 1, "WriteCapacityUnits": 1},
+    )
+    table = dynamo.Table("origin-rbu-dev")
+    table.put_item(Item={"job_id": "a", "job_name": None})
+    table.update_item(
+        Key={"job_id": "a"},
+        UpdateExpression="SET job_name = :output",
+        ExpressionAttributeValues={":output": "updated",},
+    )
+    table.scan()["Items"][0]["job_name"].should.equal("updated")
+
+
+@mock_dynamodb2
+def test_update_nested_item_if_original_value_is_none():
+    dynamo = boto3.resource("dynamodb", region_name="eu-central-1")
+    dynamo.create_table(
+        AttributeDefinitions=[{"AttributeName": "job_id", "AttributeType": "S"}],
+        TableName="origin-rbu-dev",
+        KeySchema=[{"AttributeName": "job_id", "KeyType": "HASH"}],
+        ProvisionedThroughput={"ReadCapacityUnits": 1, "WriteCapacityUnits": 1},
+    )
+    table = dynamo.Table("origin-rbu-dev")
+    table.put_item(Item={"job_id": "a", "job_details": {"job_name": None}})
+    table.update_item(
+        Key={"job_id": "a"},
+        UpdateExpression="SET job_details.job_name = :output",
+        ExpressionAttributeValues={":output": "updated",},
+    )
+    table.scan()["Items"][0]["job_details"]["job_name"].should.equal("updated")
+
+
+@mock_dynamodb2
+def test_allow_update_to_item_with_different_type():
+    dynamo = boto3.resource("dynamodb", region_name="eu-central-1")
+    dynamo.create_table(
+        AttributeDefinitions=[{"AttributeName": "job_id", "AttributeType": "S"}],
+        TableName="origin-rbu-dev",
+        KeySchema=[{"AttributeName": "job_id", "KeyType": "HASH"}],
+        ProvisionedThroughput={"ReadCapacityUnits": 1, "WriteCapacityUnits": 1},
+    )
+    table = dynamo.Table("origin-rbu-dev")
+    table.put_item(Item={"job_id": "a", "job_details": {"job_name": {"nested": "yes"}}})
+    table.put_item(Item={"job_id": "b", "job_details": {"job_name": {"nested": "yes"}}})
+    table.update_item(
+        Key={"job_id": "a"},
+        UpdateExpression="SET job_details.job_name = :output",
+        ExpressionAttributeValues={":output": "updated"},
+    )
+    table.get_item(Key={"job_id": "a"})["Item"]["job_details"][
+        "job_name"
+    ].should.be.equal("updated")
+    table.get_item(Key={"job_id": "b"})["Item"]["job_details"][
+        "job_name"
+    ].should.be.equal({"nested": "yes"})
diff --git a/tests/test_ec2/test_subnets.py b/tests/test_ec2/test_subnets.py
index f5f1af433..7bb57aab4 100644
--- a/tests/test_ec2/test_subnets.py
+++ b/tests/test_ec2/test_subnets.py
@@ -11,6 +11,7 @@ from boto.exception import EC2ResponseError
 from botocore.exceptions import ParamValidationError, ClientError
 import json
 import sure  # noqa
+import random
 
 from moto import mock_cloudformation_deprecated, mock_ec2, mock_ec2_deprecated
 
@@ -474,3 +475,127 @@ def test_create_subnets_with_overlapping_cidr_blocks():
             subnet_cidr_block
         )
     )
+
+
+@mock_ec2
+def test_available_ip_addresses_in_subnet():
+    ec2 = boto3.resource("ec2", region_name="us-west-1")
+    client = boto3.client("ec2", region_name="us-west-1")
+
+    vpc = ec2.create_vpc(CidrBlock="10.0.0.0/16")
+    cidr_range_addresses = [
+        ("10.0.0.0/16", 65531),
+        ("10.0.0.0/17", 32763),
+        ("10.0.0.0/18", 16379),
+        ("10.0.0.0/19", 8187),
+        ("10.0.0.0/20", 4091),
+        ("10.0.0.0/21", 2043),
+        ("10.0.0.0/22", 1019),
+        ("10.0.0.0/23", 507),
+        ("10.0.0.0/24", 251),
+        ("10.0.0.0/25", 123),
+        ("10.0.0.0/26", 59),
+        ("10.0.0.0/27", 27),
+        ("10.0.0.0/28", 11),
+    ]
+    for (cidr, expected_count) in cidr_range_addresses:
+        validate_subnet_details(client, vpc, cidr, expected_count)
+
+
+@mock_ec2
+def test_available_ip_addresses_in_subnet_with_enis():
+    ec2 = boto3.resource("ec2", region_name="us-west-1")
+    client = boto3.client("ec2", region_name="us-west-1")
+
+    vpc = ec2.create_vpc(CidrBlock="10.0.0.0/16")
+    # Verify behaviour for various CIDR ranges (...)
+    # Don't try to assign ENIs to /27 and /28, as there are not a lot of IP addresses to go around
+    cidr_range_addresses = [
+        ("10.0.0.0/16", 65531),
+        ("10.0.0.0/17", 32763),
+        ("10.0.0.0/18", 16379),
+        ("10.0.0.0/19", 8187),
+        ("10.0.0.0/20", 4091),
+        ("10.0.0.0/21", 2043),
+        ("10.0.0.0/22", 1019),
+        ("10.0.0.0/23", 507),
+        ("10.0.0.0/24", 251),
+        ("10.0.0.0/25", 123),
+        ("10.0.0.0/26", 59),
+    ]
+    for (cidr, expected_count) in cidr_range_addresses:
+        validate_subnet_details_after_creating_eni(client, vpc, cidr, expected_count)
+
+
+def validate_subnet_details(client, vpc, cidr, expected_ip_address_count):
+    subnet = client.create_subnet(
+        VpcId=vpc.id, CidrBlock=cidr, AvailabilityZone="us-west-1b"
+    )["Subnet"]
+    subnet["AvailableIpAddressCount"].should.equal(expected_ip_address_count)
+    client.delete_subnet(SubnetId=subnet["SubnetId"])
+
+
+def validate_subnet_details_after_creating_eni(
+    client, vpc, cidr, expected_ip_address_count
+):
+    subnet = client.create_subnet(
+        VpcId=vpc.id, CidrBlock=cidr, AvailabilityZone="us-west-1b"
+    )["Subnet"]
+    # Create a random number of Elastic Network Interfaces
+    nr_of_eni_to_create = random.randint(0, 5)
+    ip_addresses_assigned = 0
+    enis_created = []
+    for i in range(0, nr_of_eni_to_create):
+        # Create a random number of IP addresses per ENI
+        nr_of_ip_addresses = random.randint(1, 5)
+        if nr_of_ip_addresses == 1:
+            # Pick the first available IP address (First 4 are reserved by AWS)
+            private_address = "10.0.0." + str(ip_addresses_assigned + 4)
+            eni = client.create_network_interface(
+                SubnetId=subnet["SubnetId"], PrivateIpAddress=private_address
+            )["NetworkInterface"]
+            enis_created.append(eni)
+            ip_addresses_assigned = ip_addresses_assigned + 1
+        else:
+            # Assign a list of IP addresses
+            private_addresses = [
+                "10.0.0." + str(4 + ip_addresses_assigned + i)
+                for i in range(0, nr_of_ip_addresses)
+            ]
+            eni = client.create_network_interface(
+                SubnetId=subnet["SubnetId"],
+                PrivateIpAddresses=[
+                    {"PrivateIpAddress": address} for address in private_addresses
+                ],
+            )["NetworkInterface"]
+            enis_created.append(eni)
+            ip_addresses_assigned = ip_addresses_assigned + nr_of_ip_addresses + 1  #
+    # Verify that the nr of available IP addresses takes these ENIs into account
+    updated_subnet = client.describe_subnets(SubnetIds=[subnet["SubnetId"]])["Subnets"][
+        0
+    ]
+    private_addresses = [
+        eni["PrivateIpAddress"] for eni in enis_created if eni["PrivateIpAddress"]
+    ]
+    for eni in enis_created:
+        private_addresses.extend(
+            [address["PrivateIpAddress"] for address in eni["PrivateIpAddresses"]]
+        )
+    error_msg = (
+        "Nr of IP addresses for Subnet with CIDR {0} is incorrect. Expected: {1}, Actual: {2}. "
+        "Addresses: {3}"
+    )
+    with sure.ensure(
+        error_msg,
+        cidr,
+        str(expected_ip_address_count),
+        updated_subnet["AvailableIpAddressCount"],
+        str(private_addresses),
+    ):
+        updated_subnet["AvailableIpAddressCount"].should.equal(
+            expected_ip_address_count - ip_addresses_assigned
+        )
+    # Clean up, as we have to create a few more subnets that shouldn't interfere with each other
+    for eni in enis_created:
+        client.delete_network_interface(NetworkInterfaceId=eni["NetworkInterfaceId"])
+    client.delete_subnet(SubnetId=subnet["SubnetId"])
diff --git a/tests/test_events/test_events.py b/tests/test_events/test_events.py
index d5bfdf782..5f81e2cf6 100644
--- a/tests/test_events/test_events.py
+++ b/tests/test_events/test_events.py
@@ -1,6 +1,7 @@
 import random
 import boto3
 import json
+import sure  # noqa
 
 from moto.events import mock_events
 from botocore.exceptions import ClientError
@@ -204,6 +205,53 @@ def test_permissions():
     assert resp_policy["Statement"][0]["Sid"] == "Account1"
 
 
+@mock_events
+def test_put_permission_errors():
+    client = boto3.client("events", "us-east-1")
+    client.create_event_bus(Name="test-bus")
+
+    client.put_permission.when.called_with(
+        EventBusName="non-existing",
+        Action="events:PutEvents",
+        Principal="111111111111",
+        StatementId="test",
+    ).should.throw(ClientError, "Event bus non-existing does not exist.")
+
+    client.put_permission.when.called_with(
+        EventBusName="test-bus",
+        Action="events:PutPermission",
+        Principal="111111111111",
+        StatementId="test",
+    ).should.throw(
+        ClientError, "Provided value in parameter 'action' is not supported."
+    )
+
+
+@mock_events
+def test_remove_permission_errors():
+    client = boto3.client("events", "us-east-1")
+    client.create_event_bus(Name="test-bus")
+
+    client.remove_permission.when.called_with(
+        EventBusName="non-existing", StatementId="test"
+    ).should.throw(ClientError, "Event bus non-existing does not exist.")
+
+    client.remove_permission.when.called_with(
+        EventBusName="test-bus", StatementId="test"
+    ).should.throw(ClientError, "EventBus does not have a policy.")
+
+    client.put_permission(
+        EventBusName="test-bus",
+        Action="events:PutEvents",
+        Principal="111111111111",
+        StatementId="test",
+    )
+
+    client.remove_permission.when.called_with(
+        EventBusName="test-bus", StatementId="non-existing"
+    ).should.throw(ClientError, "Statement with the provided id does not exist.")
+
+
 @mock_events
 def test_put_events():
     client = boto3.client("events", "eu-central-1")
@@ -220,3 +268,177 @@ def test_put_events():
 
     with assert_raises(ClientError):
         client.put_events(Entries=[event] * 20)
+
+
+@mock_events
+def test_create_event_bus():
+    client = boto3.client("events", "us-east-1")
+    response = client.create_event_bus(Name="test-bus")
+
+    response["EventBusArn"].should.equal(
+        "arn:aws:events:us-east-1:123456789012:event-bus/test-bus"
+    )
+
+
+@mock_events
+def test_create_event_bus_errors():
+    client = boto3.client("events", "us-east-1")
+    client.create_event_bus(Name="test-bus")
+
+    client.create_event_bus.when.called_with(Name="test-bus").should.throw(
+        ClientError, "Event bus test-bus already exists."
+    )
+
+    # the 'default' name is already used for the account's default event bus.
+    client.create_event_bus.when.called_with(Name="default").should.throw(
+        ClientError, "Event bus default already exists."
+    )
+
+    # non partner event buses can't contain the '/' character
+    client.create_event_bus.when.called_with(Name="test/test-bus").should.throw(
+        ClientError, "Event bus name must not contain '/'."
+    )
+
+    client.create_event_bus.when.called_with(
+        Name="aws.partner/test/test-bus", EventSourceName="aws.partner/test/test-bus"
+    ).should.throw(
+        ClientError, "Event source aws.partner/test/test-bus does not exist."
+    )
+
+
+@mock_events
+def test_describe_event_bus():
+    client = boto3.client("events", "us-east-1")
+
+    response = client.describe_event_bus()
+
+    response["Name"].should.equal("default")
+    response["Arn"].should.equal(
+        "arn:aws:events:us-east-1:123456789012:event-bus/default"
+    )
+    response.should_not.have.key("Policy")
+
+    client.create_event_bus(Name="test-bus")
+    client.put_permission(
+        EventBusName="test-bus",
+        Action="events:PutEvents",
+        Principal="111111111111",
+        StatementId="test",
+    )
+
+    response = client.describe_event_bus(Name="test-bus")
+
+    response["Name"].should.equal("test-bus")
+    response["Arn"].should.equal(
+        "arn:aws:events:us-east-1:123456789012:event-bus/test-bus"
+    )
+    json.loads(response["Policy"]).should.equal(
+        {
+            "Version": "2012-10-17",
+            "Statement": [
+                {
+                    "Sid": "test",
+                    "Effect": "Allow",
+                    "Principal": {"AWS": "arn:aws:iam::111111111111:root"},
+                    "Action": "events:PutEvents",
+                    "Resource": "arn:aws:events:us-east-1:123456789012:event-bus/test-bus",
+                }
+            ],
+        }
+    )
+
+
+@mock_events
+def test_describe_event_bus_errors():
+    client = boto3.client("events", "us-east-1")
+
+    client.describe_event_bus.when.called_with(Name="non-existing").should.throw(
+        ClientError, "Event bus non-existing does not exist."
+    )
+
+
+@mock_events
+def test_list_event_buses():
+    client = boto3.client("events", "us-east-1")
+    client.create_event_bus(Name="test-bus-1")
+    client.create_event_bus(Name="test-bus-2")
+    client.create_event_bus(Name="other-bus-1")
+    client.create_event_bus(Name="other-bus-2")
+
+    response = client.list_event_buses()
+
+    response["EventBuses"].should.have.length_of(5)
+    sorted(response["EventBuses"], key=lambda i: i["Name"]).should.equal(
+        [
+            {
+                "Name": "default",
+                "Arn": "arn:aws:events:us-east-1:123456789012:event-bus/default",
+            },
+            {
+                "Name": "other-bus-1",
+                "Arn": "arn:aws:events:us-east-1:123456789012:event-bus/other-bus-1",
+            },
+            {
+                "Name": "other-bus-2",
+                "Arn": "arn:aws:events:us-east-1:123456789012:event-bus/other-bus-2",
+            },
+            {
+                "Name": "test-bus-1",
+                "Arn": "arn:aws:events:us-east-1:123456789012:event-bus/test-bus-1",
+            },
+            {
+                "Name": "test-bus-2",
+                "Arn": "arn:aws:events:us-east-1:123456789012:event-bus/test-bus-2",
+            },
+        ]
+    )
+
+    response = client.list_event_buses(NamePrefix="other-bus")
+
+    response["EventBuses"].should.have.length_of(2)
+    sorted(response["EventBuses"], key=lambda i: i["Name"]).should.equal(
+        [
+            {
+                "Name": "other-bus-1",
+                "Arn": "arn:aws:events:us-east-1:123456789012:event-bus/other-bus-1",
+            },
+            {
+                "Name": "other-bus-2",
+                "Arn": "arn:aws:events:us-east-1:123456789012:event-bus/other-bus-2",
+            },
+        ]
+    )
+
+
+@mock_events
+def test_delete_event_bus():
+    client = boto3.client("events", "us-east-1")
+    client.create_event_bus(Name="test-bus")
+
+    response = client.list_event_buses()
+    response["EventBuses"].should.have.length_of(2)
+
+    client.delete_event_bus(Name="test-bus")
+
+    response = client.list_event_buses()
+    response["EventBuses"].should.have.length_of(1)
+    response["EventBuses"].should.equal(
+        [
+            {
+                "Name": "default",
+                "Arn": "arn:aws:events:us-east-1:123456789012:event-bus/default",
+            }
+        ]
+    )
+
+    # deleting non existing event bus should be successful
+    client.delete_event_bus(Name="non-existing")
+
+
+@mock_events
+def test_delete_event_bus_errors():
+    client = boto3.client("events", "us-east-1")
+
+    client.delete_event_bus.when.called_with(Name="default").should.throw(
+        ClientError, "Cannot delete event bus default."
+    )
diff --git a/tests/test_iam/test_iam.py b/tests/test_iam/test_iam.py
index 8eea201d0..c5e856b68 100644
--- a/tests/test_iam/test_iam.py
+++ b/tests/test_iam/test_iam.py
@@ -408,6 +408,21 @@ def test_create_policy():
     )
 
 
+@mock_iam
+def test_create_policy_already_exists():
+    conn = boto3.client("iam", region_name="us-east-1")
+    response = conn.create_policy(
+        PolicyName="TestCreatePolicy", PolicyDocument=MOCK_POLICY
+    )
+    with assert_raises(conn.exceptions.EntityAlreadyExistsException) as ex:
+        response = conn.create_policy(
+            PolicyName="TestCreatePolicy", PolicyDocument=MOCK_POLICY
+        )
+    ex.exception.response["Error"]["Code"].should.equal("EntityAlreadyExists")
+    ex.exception.response["ResponseMetadata"]["HTTPStatusCode"].should.equal(409)
+    ex.exception.response["Error"]["Message"].should.contain("TestCreatePolicy")
+
+
 @mock_iam
 def test_delete_policy():
     conn = boto3.client("iam", region_name="us-east-1")
diff --git a/tests/test_iam/test_iam_groups.py b/tests/test_iam/test_iam_groups.py
index 7fd299281..7b73e89ea 100644
--- a/tests/test_iam/test_iam_groups.py
+++ b/tests/test_iam/test_iam_groups.py
@@ -8,6 +8,7 @@ import sure  # noqa
 
 from nose.tools import assert_raises
 from boto.exception import BotoServerError
+from botocore.exceptions import ClientError
 from moto import mock_iam, mock_iam_deprecated
 
 MOCK_POLICY = """
@@ -182,3 +183,25 @@ def test_list_group_policies():
     conn.list_group_policies(GroupName="my-group")["PolicyNames"].should.equal(
         ["my-policy"]
     )
+
+
+@mock_iam
+def test_delete_group():
+    conn = boto3.client("iam", region_name="us-east-1")
+    conn.create_group(GroupName="my-group")
+    groups = conn.list_groups()
+    assert groups["Groups"][0]["GroupName"] == "my-group"
+    assert len(groups["Groups"]) == 1
+    conn.delete_group(GroupName="my-group")
+    conn.list_groups()["Groups"].should.be.empty
+
+
+@mock_iam
+def test_delete_unknown_group():
+    conn = boto3.client("iam", region_name="us-east-1")
+    with assert_raises(ClientError) as err:
+        conn.delete_group(GroupName="unknown-group")
+    err.exception.response["Error"]["Code"].should.equal("NoSuchEntity")
+    err.exception.response["Error"]["Message"].should.equal(
+        "The group with name unknown-group cannot be found."
+    )
diff --git a/tests/test_organizations/test_organizations_boto3.py b/tests/test_organizations/test_organizations_boto3.py
index f8eb1328e..3b4a51557 100644
--- a/tests/test_organizations/test_organizations_boto3.py
+++ b/tests/test_organizations/test_organizations_boto3.py
@@ -159,6 +159,17 @@ def test_create_account():
     create_status["AccountName"].should.equal(mockname)
 
 
+@mock_organizations
+def test_describe_create_account_status():
+    client = boto3.client("organizations", region_name="us-east-1")
+    client.create_organization(FeatureSet="ALL")["Organization"]
+    request_id = client.create_account(AccountName=mockname, Email=mockemail)[
+        "CreateAccountStatus"
+    ]["Id"]
+    response = client.describe_create_account_status(CreateAccountRequestId=request_id)
+    validate_create_account_status(response["CreateAccountStatus"])
+
+
 @mock_organizations
 def test_describe_account():
     client = boto3.client("organizations", region_name="us-east-1")
diff --git a/tests/test_secretsmanager/test_secretsmanager.py b/tests/test_secretsmanager/test_secretsmanager.py
index bf688ec12..a7c7a6862 100644
--- a/tests/test_secretsmanager/test_secretsmanager.py
+++ b/tests/test_secretsmanager/test_secretsmanager.py
@@ -45,7 +45,7 @@ def test_get_secret_that_does_not_exist():
         result = conn.get_secret_value(SecretId="i-dont-exist")
 
     assert_equal(
-        "Secrets Manager can\u2019t find the specified secret.",
+        "Secrets Manager can't find the specified secret.",
         cm.exception.response["Error"]["Message"],
     )
 
@@ -61,7 +61,7 @@ def test_get_secret_that_does_not_match():
         result = conn.get_secret_value(SecretId="i-dont-match")
 
     assert_equal(
-        "Secrets Manager can\u2019t find the specified secret.",
+        "Secrets Manager can't find the specified secret.",
         cm.exception.response["Error"]["Message"],
     )
 
@@ -88,7 +88,7 @@ def test_get_secret_that_has_no_value():
         result = conn.get_secret_value(SecretId="java-util-test-password")
 
     assert_equal(
-        "Secrets Manager can\u2019t find the specified secret value for staging label: AWSCURRENT",
+        "Secrets Manager can't find the specified secret value for staging label: AWSCURRENT",
         cm.exception.response["Error"]["Message"],
     )
 
diff --git a/tests/test_secretsmanager/test_server.py b/tests/test_secretsmanager/test_server.py
index 89cb90185..9501c7c7c 100644
--- a/tests/test_secretsmanager/test_server.py
+++ b/tests/test_secretsmanager/test_server.py
@@ -48,9 +48,7 @@ def test_get_secret_that_does_not_exist():
         headers={"X-Amz-Target": "secretsmanager.GetSecretValue"},
     )
     json_data = json.loads(get_secret.data.decode("utf-8"))
-    assert (
-        json_data["message"] == "Secrets Manager can\u2019t find the specified secret."
-    )
+    assert json_data["message"] == "Secrets Manager can't find the specified secret."
     assert json_data["__type"] == "ResourceNotFoundException"
 
 
@@ -70,9 +68,7 @@ def test_get_secret_that_does_not_match():
         headers={"X-Amz-Target": "secretsmanager.GetSecretValue"},
     )
     json_data = json.loads(get_secret.data.decode("utf-8"))
-    assert (
-        json_data["message"] == "Secrets Manager can\u2019t find the specified secret."
-    )
+    assert json_data["message"] == "Secrets Manager can't find the specified secret."
     assert json_data["__type"] == "ResourceNotFoundException"
 
 
@@ -95,7 +91,7 @@ def test_get_secret_that_has_no_value():
     json_data = json.loads(get_secret.data.decode("utf-8"))
     assert (
         json_data["message"]
-        == "Secrets Manager can\u2019t find the specified secret value for staging label: AWSCURRENT"
+        == "Secrets Manager can't find the specified secret value for staging label: AWSCURRENT"
     )
     assert json_data["__type"] == "ResourceNotFoundException"
 
@@ -178,9 +174,7 @@ def test_describe_secret_that_does_not_exist():
     )
 
     json_data = json.loads(describe_secret.data.decode("utf-8"))
-    assert (
-        json_data["message"] == "Secrets Manager can\u2019t find the specified secret."
-    )
+    assert json_data["message"] == "Secrets Manager can't find the specified secret."
     assert json_data["__type"] == "ResourceNotFoundException"
 
 
@@ -202,9 +196,7 @@ def test_describe_secret_that_does_not_match():
     )
 
     json_data = json.loads(describe_secret.data.decode("utf-8"))
-    assert (
-        json_data["message"] == "Secrets Manager can\u2019t find the specified secret."
-    )
+    assert json_data["message"] == "Secrets Manager can't find the specified secret."
     assert json_data["__type"] == "ResourceNotFoundException"
 
 
@@ -306,9 +298,7 @@ def test_rotate_secret_that_does_not_exist():
     )
 
     json_data = json.loads(rotate_secret.data.decode("utf-8"))
-    assert (
-        json_data["message"] == "Secrets Manager can\u2019t find the specified secret."
-    )
+    assert json_data["message"] == "Secrets Manager can't find the specified secret."
     assert json_data["__type"] == "ResourceNotFoundException"
 
 
@@ -330,9 +320,7 @@ def test_rotate_secret_that_does_not_match():
     )
 
     json_data = json.loads(rotate_secret.data.decode("utf-8"))
-    assert (
-        json_data["message"] == "Secrets Manager can\u2019t find the specified secret."
-    )
+    assert json_data["message"] == "Secrets Manager can't find the specified secret."
     assert json_data["__type"] == "ResourceNotFoundException"