diff --git a/osm_mon/collector/vnf_collectors/vmware.py b/osm_mon/collector/vnf_collectors/vmware.py
index 438c40c..00ef9ef 100644
--- a/osm_mon/collector/vnf_collectors/vmware.py
+++ b/osm_mon/collector/vnf_collectors/vmware.py
@@ -28,7 +28,6 @@
 from xml.etree import ElementTree as XmlElementTree
 
 import requests
-import six
 from pyvcloud.vcd.client import BasicLoginCredentials
 from pyvcloud.vcd.client import Client
 
@@ -42,24 +41,83 @@
 
 API_VERSION = '27.0'
 
-PERIOD_MSEC = {'HR': 3600000,
-               'DAY': 86400000,
-               'WEEK': 604800000,
-               'MONTH': 2678400000,
-               'YEAR': 31536000000}
+TEN_MINUTES = 600000
+
+# Ref: https://docs.vmware.com/en/vRealize-Operations-Manager/7.0/vrealize-operations-manager-70-reference-guide.pdf
+# Potential metrics of interest
+# "cpu|capacity_contentionPct"
+# "cpu|corecount_provisioned"
+# "cpu|costopPct"
+# "cpu|demandmhz"
+# "cpu|demandPct"
+# "cpu|effective_limit"
+# "cpu|iowaitPct"
+# "cpu|readyPct"
+# "cpu|swapwaitPct"
+# "cpu|usage_average"
+# "cpu|usagemhz_average"
+# "cpu|usagemhz_average_mtd"
+# "cpu|vm_capacity_provisioned"
+# "cpu|workload"
+# "guestfilesystem|percentage_total"
+# "guestfilesystem|usage_total"
+# "mem|consumedPct"
+# "mem|guest_usage"
+# "mem|host_contentionPct"
+# "mem|reservation_used"
+# "mem|swapinRate_average"
+# "mem|swapoutRate_average"
+# "mem|swapped_average"
+# "mem|usage_average"
+# "net:Aggregate of all instances|droppedPct"
+# "net|broadcastTx_summation"
+# "net|droppedTx_summation"
+# "net|multicastTx_summation"
+# "net|pnicBytesRx_average"
+# "net|pnicBytesTx_average"
+# "net|received_average"
+# "net|transmitted_average"
+# "net|usage_average"
+# "virtualDisk:Aggregate of all instances|commandsAveraged_average"
+# "virtualDisk:Aggregate of all instances|numberReadAveraged_average"
+# "virtualDisk:Aggregate of all instances|numberWriteAveraged_average"
+# "virtualDisk:Aggregate of all instances|totalLatency"
+# "virtualDisk:Aggregate of all instances|totalReadLatency_average"
+# "virtualDisk:Aggregate of all instances|totalWriteLatency_average"
+# "virtualDisk:Aggregate of all instances|usage"
+# "virtualDisk:Aggregate of all instances|vDiskOIO"
+# "virtualDisk|read_average"
+# "virtualDisk|write_average"
 
 METRIC_MAPPINGS = {
+    # Percent guest operating system active memory
     "average_memory_utilization": "mem|usage_average",
+    # Percentage of CPU that was used out of all the CPU that was allocated
     "cpu_utilization": "cpu|usage_average",
-    "read_latency_0": "virtualDisk:scsi0:0|totalReadLatency_average",
-    "write_latency_0": "virtualDisk:scsi0:0|totalWriteLatency_average",
-    "read_latency_1": "virtualDisk:scsi0:1|totalReadLatency_average",
-    "write_latency_1": "virtualDisk:scsi0:1|totalWriteLatency_average",
-    "packets_dropped_0": "net:4000|dropped",
-    "packets_dropped_1": "net:4001|dropped",
-    "packets_dropped_2": "net:4002|dropped",
-    "packets_received": "net:Aggregate of all instances|packetsRxPerSec",
-    "packets_sent": "net:Aggregate of all instances|packetsTxPerSec",
+    # KB/s of data read in the performance interval
+    "disk_read_bytes": "virtualDisk|read_average",
+    # Average of read commands per second during the collection interval.
+    "disk_read_ops": "virtualDisk:aggregate of all instances|numberReadAveraged_average",
+    # KB/s  of data written in the performance interval
+    "disk_write_bytes": "virtualDisk|write_average",
+    # Average of write commands per second during the collection interval.
+    "disk_write_ops": "virtualDisk:aggregate of all instances|numberWriteAveraged_average",
+    # "packets_in_dropped": "net|droppedRx_summation",  # Not supported by vROPS
+    # Transmitted packets dropped in the collection interval
+    "packets_out_dropped": "net|droppedTx_summation",
+    # Bytes received in the performance interval
+    "packets_received": "net|received_average",
+    # Packets transmitted in the performance interval
+    "packets_sent": "net|transmitted_average",
+}
+
+# If the unit from vROPS does not align with the expected value. multiply by the specified amount to ensure
+# the correct unit is returned.
+METRIC_MULTIPLIERS = {
+    "disk_read_bytes": 1024,
+    "disk_write_bytes": 1024,
+    "net_bytes_received": 1024,
+    "net_bytes_sent": 1024
 }
 
 
@@ -175,7 +233,6 @@
         Returns - VM MOref ID or return None
         """
         parsed_respond = {}
-        vca = None
 
         if vapp_uuid is None:
             return parsed_respond
@@ -282,69 +339,76 @@
                 filter(lambda vdu: vdu['id'] == vdur['vdu-id-ref'], vnfd['vdu'])
 
             )
-            if 'monitoring-param' in vdu:
-                for param in vdu['monitoring-param']:
-                    metric_name = param['nfvi-metric']
-                    vrops_metric_name = METRIC_MAPPINGS[metric_name]
-                    resource_uuid = self._get_resource_uuid(nsr_id, vnf_member_index, vdur['name'])
 
-                    # Find vm_moref_id from vApp uuid in vCD
-                    vm_moref_id = self.get_vm_moref_id(resource_uuid)
-                    if vm_moref_id is None:
-                        log.debug("Failed to find vm morefid for vApp in vCD: {}".format(resource_uuid))
-                        return
+            if 'monitoring-param' not in vdu:
+                continue
 
-                    # Based on vm_moref_id, find VM's corresponding resource_id in vROPs
-                    resource_id = self.get_vm_resource_id(vm_moref_id)
-                    if resource_id is None:
-                        log.debug("Failed to find resource in vROPs: {}".format(resource_uuid))
-                        return
-                    try:
-                        end_time = int(round(time.time() * 1000))
-                        time_diff = PERIOD_MSEC['YEAR']
-                        begin_time = end_time - time_diff
+            resource_uuid = self._get_resource_uuid(nsr_id, vnf_member_index, vdur['name'])
 
-                        api_url = "/suite-api/api/resources/{}/stats?statKey={}&begin={}&end={}".format(
-                            resource_id, vrops_metric_name, str(begin_time), str(end_time))
+            # Find vm_moref_id from vApp uuid in vCD
+            vm_moref_id = self.get_vm_moref_id(resource_uuid)
+            if vm_moref_id is None:
+                log.debug("Failed to find vm morefid for vApp in vCD: {}".format(resource_uuid))
+                continue
 
-                        headers = {'Accept': 'application/json'}
+            # Based on vm_moref_id, find VM's corresponding resource_id in vROPs
+            resource_id = self.get_vm_resource_id(vm_moref_id)
+            if resource_id is None:
+                log.debug("Failed to find resource in vROPs: {}".format(resource_uuid))
+                continue
 
-                        resp = requests.get(self.vrops_site + api_url,
-                                            auth=(self.vrops_user, self.vrops_password), verify=False, headers=headers
-                                            )
+            stat_key = ""
+            monitoring_params = []
+            for metric_entry in vdu['monitoring-param']:
+                metric_name = metric_entry['nfvi-metric']
+                if metric_name not in METRIC_MAPPINGS:
+                    log.debug("Metric {} not supported, ignoring".format(metric_name))
+                    continue
+                monitoring_params.append(metric_name)
+                vrops_metric_name = METRIC_MAPPINGS[metric_name]
+                stat_key = "{}&statKey={}".format(stat_key, vrops_metric_name)
 
-                        if resp.status_code != 200:
-                            log.info("Failed to get Metrics data from vROPS for {} {} {}".format(vrops_metric_name,
-                                                                                                 resp.status_code,
-                                                                                                 resp.content))
-                            return
+            try:
+                end_time = int(round(time.time() * 1000))
+                begin_time = end_time - TEN_MINUTES
 
-                        metrics_data = {}
-                        m_data = json.loads(resp.content.decode('utf-8'))
+                api_url = "/suite-api/api/resources/stats?resourceId={}&begin={}&end={}{}".format(
+                    resource_id, str(begin_time), str(end_time), stat_key)
+                headers = {'Accept': 'application/json'}
 
-                        for resp_key, resp_val in six.iteritems(m_data):
-                            if resp_key == 'values':
-                                data = m_data['values'][0]
-                                for data_k, data_v in six.iteritems(data):
-                                    if data_k == 'stat-list':
-                                        stat_list = data_v
-                                        for stat_list_k, stat_list_v in six.iteritems(stat_list):
-                                            for stat_keys, stat_vals in six.iteritems(stat_list_v[0]):
-                                                if stat_keys == 'timestamps':
-                                                    metrics_data['time_series'] = stat_list_v[0]['timestamps']
-                                                if stat_keys == 'data':
-                                                    metrics_data['metrics_series'] = stat_list_v[0]['data']
+                resp = requests.get(self.vrops_site + api_url,
+                                    auth=(self.vrops_user, self.vrops_password), verify=False, headers=headers
+                                    )
 
-                        if metrics_data:
-                            metric = VnfMetric(nsr_id,
-                                               vnf_member_index,
-                                               vdur['name'],
-                                               metric_name,
-                                               metrics_data['metrics_series'][-1])
+                if resp.status_code != 200:
+                    log.info("Failed to get Metrics data from vROPS for {} {} {}".format(vdur.name,
+                                                                                         resp.status_code,
+                                                                                         resp.content))
+                    continue
 
-                            metrics.append(metric)
+                m_data = json.loads(resp.content.decode('utf-8'))
 
-                    except Exception as e:
-                        log.debug("No metric found: %s", e)
-                        pass
+                stat_list = m_data['values'][0]['stat-list']['stat']
+                for item in stat_list:
+                    reported_metric = item['statKey']['key']
+                    if reported_metric not in METRIC_MAPPINGS.values():
+                        continue
+
+                    metric_name = list(METRIC_MAPPINGS.keys())[list(METRIC_MAPPINGS.values()).
+                                                               index(reported_metric)]
+                    if metric_name in monitoring_params:
+                        metric_value = item['data'][-1]
+                        if metric_name in METRIC_MULTIPLIERS:
+                            metric_value *= METRIC_MULTIPLIERS[metric_name]
+                        metric = VnfMetric(nsr_id,
+                                           vnf_member_index,
+                                           vdur['name'],
+                                           metric_name,
+                                           metric_value)
+
+                        metrics.append(metric)
+
+            except Exception as e:
+                log.debug("No metric found for {}: %s".format(vdur['name']), e)
+                pass
         return metrics
diff --git a/osm_mon/tests/unit/collector/vnf_collectors/vmware/__init__.py b/osm_mon/tests/unit/collector/vnf_collectors/vmware/__init__.py
new file mode 100644
index 0000000..30d864e
--- /dev/null
+++ b/osm_mon/tests/unit/collector/vnf_collectors/vmware/__init__.py
@@ -0,0 +1,21 @@
+# -*- coding: utf-8 -*-
+# #
+# Copyright 2016-2019 VMware Inc.
+# This file is part of ETSI OSM
+# All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+#
+# For those usages not covered by the Apache License, Version 2.0 please
+# contact:  osslegalrouting@vmware.com
+# #
diff --git a/osm_mon/tests/unit/collector/vnf_collectors/vmware/mock_vcd.py b/osm_mon/tests/unit/collector/vnf_collectors/vmware/mock_vcd.py
new file mode 100644
index 0000000..6938873
--- /dev/null
+++ b/osm_mon/tests/unit/collector/vnf_collectors/vmware/mock_vcd.py
@@ -0,0 +1,34 @@
+# -*- coding: utf-8 -*-
+# Copyright 2019 VMware
+# *************************************************************
+
+# This file is part of OSM Monitoring module
+# All Rights Reserved to VMware
+
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+
+#         http://www.apache.org/licenses/LICENSE-2.0
+
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+# For those usages not covered by the Apache License, Version 2.0 please
+# contact: mbeierl@vmware.com
+# #
+
+import os
+import re
+
+
+def mock_vdc_response(mocker, method='GET', site='https://vrops', url_pattern='', response_file='OK'):
+    '''Helper function to load a canned response from a file.'''
+    with open(os.path.join(os.path.dirname(__file__), 'vcd_mocks',
+                           '%s' % response_file), 'r') as f:
+        response = f.read()
+
+    matcher = re.compile(site + url_pattern)
+    mocker.register_uri(method, matcher, text=response)
diff --git a/osm_mon/tests/unit/collector/vnf_collectors/vmware/osm_mocks/VNFD.json b/osm_mon/tests/unit/collector/vnf_collectors/vmware/osm_mocks/VNFD.json
new file mode 100644
index 0000000..ed34789
--- /dev/null
+++ b/osm_mon/tests/unit/collector/vnf_collectors/vmware/osm_mocks/VNFD.json
@@ -0,0 +1,123 @@
+{
+	"_admin": {
+		"created": 1561567611.6193357,
+		"modified": 1561567611.6193357,
+		"onboardingState": "ONBOARDED",
+		"operationalState": "ENABLED",
+		"projects_read": [
+			"admin"
+		],
+		"projects_write": [
+			"admin"
+		],
+		"storage": {
+			"descriptor": "cirros_vnf/cirros_vdu_alarm_vnfd.yaml",
+			"folder": "9d116df6-6fa7-4a5b-b284-a67f554c1261",
+			"fs": "local",
+			"path": "/app/storage/",
+			"pkg-dir": "cirros_vnf",
+			"zipfile": "cirros_vdu_alarm_vnfd.tar.gz"
+		},
+		"type": "vnfd",
+		"usageState": "NOT_IN_USE",
+		"userDefinedData": {
+		}
+	},
+	"_id": "9d116df6-6fa7-4a5b-b284-a67f554c1261",
+	"connection-point": [
+		{
+			"name": "eth0",
+			"type": "VPORT"
+		}
+	],
+	"description": "Simple VNF example with a cirros and a VNF alarm",
+	"id": "cirros_vdu_alarm_vnf",
+	"logo": "cirros-64.png",
+	"mgmt-interface": {
+		"cp": "eth0"
+	},
+	"monitoring-param": [
+		{
+			"aggregation-type": "AVERAGE",
+			"id": "cirros_vnf_cpu_util",
+			"name": "cirros_vnf_cpu_util",
+			"vdu-monitoring-param": {
+				"vdu-monitoring-param-ref": "cirros_vnfd-VM_cpu_util",
+				"vdu-ref": "cirros_vnfd-VM"
+			}
+		},
+		{
+			"aggregation-type": "AVERAGE",
+			"id": "cirros_vnf_average_memory_utilization",
+			"name": "cirros_vnf_average_memory_utilization",
+			"vdu-monitoring-param": {
+				"vdu-monitoring-param-ref": "cirros_vnfd-VM_average_memory_utilization",
+				"vdu-ref": "cirros_vnfd-VM"
+			}
+		}
+	],
+	"name": "cirros_vdu_alarm_vnf",
+	"short-name": "cirros_vdu_alarm_vnf",
+	"vdu": [
+		{
+			"alarm": [
+				{
+					"actions": {
+						"alarm": [
+							{
+								"url": "https://webhook.site/e65ad8a0-53b5-4d7f-bd50-c1a50b260871"
+							}
+						],
+						"insufficient-data": [
+							{
+								"url": "https://webhook.site/e65ad8a0-53b5-4d7f-bd50-c1a50b260871"
+							}
+						],
+						"ok": [
+							{
+								"url": "https://webhook.site/e65ad8a0-53b5-4d7f-bd50-c1a50b260871"
+							}
+						]
+					},
+					"alarm-id": "alarm-1",
+					"operation": "LT",
+					"value": "20.0000",
+					"vnf-monitoring-param-ref": "cirros_vnf_cpu_util"
+				}
+			],
+			"count": "1",
+			"description": "cirros_vnfd-VM",
+			"id": "cirros_vnfd-VM",
+			"image": "ubuntu",
+			"interface": [
+				{
+					"external-connection-point-ref": "eth0",
+					"name": "eth0",
+					"virtual-interface": {
+						"bandwidth": "0",
+						"type": "VIRTIO",
+						"vpci": "0000:00:0a.0"
+					}
+				}
+			],
+			"monitoring-param": [
+				{
+					"id": "cirros_vnfd-VM_cpu_util",
+					"nfvi-metric": "cpu_utilization"
+				},
+				{
+					"id": "cirros_vnfd-VM_average_memory_utilization",
+					"nfvi-metric": "average_memory_utilization"
+				}
+			],
+			"name": "cirros_vnfd-VM",
+			"vm-flavor": {
+				"memory-mb": "256",
+				"storage-gb": "2",
+				"vcpu-count": 1
+			}
+		}
+	],
+	"vendor": "OSM",
+	"version": "1.0"
+}
diff --git a/osm_mon/tests/unit/collector/vnf_collectors/vmware/osm_mocks/VNFR.json b/osm_mon/tests/unit/collector/vnf_collectors/vmware/osm_mocks/VNFR.json
new file mode 100644
index 0000000..332949b
--- /dev/null
+++ b/osm_mon/tests/unit/collector/vnf_collectors/vmware/osm_mocks/VNFR.json
@@ -0,0 +1,52 @@
+{
+	"_admin": {
+		"created": 1561569715.5365124,
+		"modified": 1561569715.5365124,
+		"projects_read": [
+			"admin"
+		],
+		"projects_write": [
+			"admin"
+		]
+	},
+	"_id": "c222366b-4e67-47e8-a3a5-d602ef9f953f",
+	"additionalParamsForVnf": null,
+	"connection-point": [
+		{
+			"connection-point-id": null,
+			"id": null,
+			"name": "eth0"
+		}
+	],
+	"created-time": 1561569715.5344007,
+	"id": "c222366b-4e67-47e8-a3a5-d602ef9f953f",
+	"ip-address": "172.21.6.212",
+	"member-vnf-index-ref": "1",
+	"nsr-id-ref": "66300531-3fb2-43e2-a988-51a1afd9a8f2",
+	"vdur": [
+		{
+			"_id": "ddb46f3c-d586-4a8e-80c3-87a74d0a3b37",
+			"count-index": 0,
+			"interfaces": [
+				{
+					"ip-address": "172.21.6.212",
+					"mac-address": "00:50:56:03:01:79",
+					"mgmt-vnf": true,
+					"name": "eth0",
+					"ns-vld-id": "cirros_nsd_vld1"
+				}
+			],
+			"internal-connection-point": [
+			],
+			"ip-address": "172.21.6.212",
+			"name": "mb-cirros-1-cirros_vnfd-VM-1",
+			"status": "ACTIVE",
+			"status-detailed": "ACTIVE",
+			"vdu-id-ref": "cirros_vnfd-VM",
+			"vim-id": "962e29e7-e0b0-4253-b3ef-88df7971f12e"
+		}
+	],
+	"vim-account-id": "43d176fd-dc6d-4fb0-acf3-faf03b1d2589",
+	"vnfd-id": "9d116df6-6fa7-4a5b-b284-a67f554c1261",
+	"vnfd-ref": "cirros_vdu_alarm_vnf"
+}
diff --git a/osm_mon/tests/unit/collector/vnf_collectors/vmware/test_vcd_collector.py b/osm_mon/tests/unit/collector/vnf_collectors/vmware/test_vcd_collector.py
new file mode 100644
index 0000000..19d1496
--- /dev/null
+++ b/osm_mon/tests/unit/collector/vnf_collectors/vmware/test_vcd_collector.py
@@ -0,0 +1,160 @@
+# -*- coding: utf-8 -*-
+# #
+# Copyright 2016-2019 VMware Inc.
+# This file is part of ETSI OSM
+# All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+#
+# For those usages not covered by the Apache License, Version 2.0 please
+# contact:  osslegalrouting@vmware.com
+# #
+
+from osm_mon.collector.vnf_collectors.vmware import VMwareCollector
+from osm_mon.core.config import Config
+from osm_mon.tests.unit.collector.vnf_collectors.vmware.mock_vcd import mock_vdc_response
+from unittest import TestCase, mock
+
+import json
+import os
+import requests_mock
+
+VIM_ACCOUNT = {"vrops_site": "https://vrops",
+               "vrops_user": "",
+               "vrops_password": "",
+               "vim_url": "",
+               "admin_username": "",
+               "admin_password": "",
+               "vim_uuid": ""}
+
+
+@mock.patch.object(VMwareCollector, 'get_vm_resource_id',
+                   spec_set=True, autospec=True)
+@mock.patch.object(VMwareCollector, 'get_vm_moref_id',
+                   spec_set=True, autospec=True)
+class CollectorTest(TestCase):
+
+    @mock.patch.object(VMwareCollector, 'get_vim_account',
+                       spec_set=True, autospec=True)
+    @mock.patch('osm_mon.collector.vnf_collectors.vmware.CommonDbClient')
+    def setUp(self, mock_db, mock_get_vim_account):
+        super().setUp()
+        mock_get_vim_account.return_value = VIM_ACCOUNT
+        self.collector = VMwareCollector(Config(), "9de6df67-b820-48c3-bcae-ee4838c5c5f4")
+        self.mock_db = mock_db
+        with open(os.path.join(os.path.dirname(__file__), 'osm_mocks', 'VNFR.json'), 'r') as f:
+            self.vnfr = json.load(f)
+        with open(os.path.join(os.path.dirname(__file__), 'osm_mocks', 'VNFD.json'), 'r') as f:
+            self.vnfd = json.load(f)
+
+    def tearDown(self):
+        super().tearDown()
+
+    def test_collect_cpu_and_memory(self, mock_vm_moref_id, mock_vm_resource_id):
+
+        mock_vm_moref_id.return_value = "moref"
+        mock_vm_resource_id.return_value = "resource"
+        self.mock_db.return_value.get_vnfd.return_value = self.vnfd
+
+        with requests_mock.Mocker() as mock_requests:
+            mock_vdc_response(mock_requests,
+                              url_pattern='/suite-api/api/resources/stats.*',
+                              response_file='vrops_multi.json')
+            metrics = self.collector.collect(self.vnfr)
+            self.assertEqual(len(metrics), 2, "Number of metrics returned")
+            self.assertEqual(metrics[0].name, "cpu_utilization", "First metric name")
+            self.assertEqual(metrics[1].name, "average_memory_utilization", "Second metric name")
+            self.assertEqual(metrics[0].value, 100.0, "CPU metric value")
+            self.assertEqual(metrics[1].value, 20.515941619873047, "Memory metric value")
+
+    def test_collect_one_metric_only(self, mock_vm_moref_id, mock_vm_resource_id):
+
+        mock_vm_moref_id.return_value = "moref"
+        mock_vm_resource_id.return_value = "resource"
+
+        self.vnfd['vdu'][0]['monitoring-param'] = [
+            {'id': 'cirros_vnfd-VM_cpu_util', 'nfvi-metric': 'cpu_utilization'},
+            ]
+        self.mock_db.return_value.get_vnfd.return_value = self.vnfd
+
+        with requests_mock.Mocker() as mock_requests:
+            mock_vdc_response(mock_requests,
+                              url_pattern='/suite-api/api/resources/stats.*',
+                              response_file='vrops_multi.json')
+            metrics = self.collector.collect(self.vnfr)
+            self.assertEqual(len(metrics), 1, "Number of metrics returned")
+            self.assertEqual(metrics[0].name, "cpu_utilization", "First metric name")
+            self.assertEqual(metrics[0].value, 100.0, "CPU metric value")
+
+    def test_collect_adjusted_metric(self, mock_vm_moref_id, mock_vm_resource_id):
+
+        mock_vm_moref_id.return_value = "moref"
+        mock_vm_resource_id.return_value = "resource"
+
+        self.vnfd['vdu'][0]['monitoring-param'] = [
+            {'id': 'cirros_vnfd-VM_cpu_util', 'nfvi-metric': 'disk_read_bytes'},
+            ]
+        self.mock_db.return_value.get_vnfd.return_value = self.vnfd
+
+        with requests_mock.Mocker() as mock_requests:
+            mock_vdc_response(mock_requests,
+                              url_pattern='/suite-api/api/resources/stats.*',
+                              response_file='vrops_multi.json')
+            metrics = self.collector.collect(self.vnfr)
+            self.assertEqual(len(metrics), 1, "Number of metrics returned")
+            self.assertEqual(metrics[0].name, "disk_read_bytes", "First metric name")
+            self.assertEqual(metrics[0].value, 10240.0, "Disk read bytes (not KB/s)")
+
+    def test_collect_not_provided_metric(self, mock_vm_moref_id, mock_vm_resource_id):
+
+        mock_vm_moref_id.return_value = "moref"
+        mock_vm_resource_id.return_value = "resource"
+
+        self.vnfd['vdu'][0]['monitoring-param'] = [
+            {'id': 'cirros_vnfd-VM_packets_sent', 'nfvi-metric': 'packets_sent'},
+            ]
+        self.mock_db.return_value.get_vnfd.return_value = self.vnfd
+
+        with requests_mock.Mocker() as mock_requests:
+            mock_vdc_response(mock_requests,
+                              url_pattern='/suite-api/api/resources/stats.*',
+                              response_file='OK.json')
+            metrics = self.collector.collect(self.vnfr)
+            self.assertEqual(len(metrics), 0, "Number of metrics returned")
+
+    def test_collect_unkown_metric(self, mock_vm_moref_id, mock_vm_resource_id):
+
+        mock_vm_moref_id.return_value = "moref"
+        mock_vm_resource_id.return_value = "resource"
+
+        self.vnfd['vdu'][0]['monitoring-param'] = [
+            {'id': 'cirros_vnfd-Unknown_Metric', 'nfvi-metric': 'unknown'},
+            ]
+        self.mock_db.return_value.get_vnfd.return_value = self.vnfd
+
+        with requests_mock.Mocker() as mock_requests:
+            mock_vdc_response(mock_requests,
+                              url_pattern='/suite-api/api/resources/stats.*',
+                              response_file='vrops_multi.json')
+            metrics = self.collector.collect(self.vnfr)
+            self.assertEqual(len(metrics), 0, "Number of metrics returned")
+
+    def test_collect_vrops_error(self, mock_vm_moref_id, mock_vm_resource_id):
+
+        mock_vm_moref_id.return_value = "moref"
+        mock_vm_resource_id.return_value = "resource"
+        self.mock_db.return_value.get_vnfd.return_value = self.vnfd
+
+        with requests_mock.Mocker():
+            metrics = self.collector.collect(self.vnfr)
+            self.assertEqual(len(metrics), 0, "Number of metrics returned")
diff --git a/osm_mon/tests/unit/collector/vnf_collectors/vmware/vcd_mocks/OK.json b/osm_mon/tests/unit/collector/vnf_collectors/vmware/vcd_mocks/OK.json
new file mode 100644
index 0000000..0967ef4
--- /dev/null
+++ b/osm_mon/tests/unit/collector/vnf_collectors/vmware/vcd_mocks/OK.json
@@ -0,0 +1 @@
+{}
diff --git a/osm_mon/tests/unit/collector/vnf_collectors/vmware/vcd_mocks/vrops_multi.json b/osm_mon/tests/unit/collector/vnf_collectors/vmware/vcd_mocks/vrops_multi.json
new file mode 100644
index 0000000..95b0305
--- /dev/null
+++ b/osm_mon/tests/unit/collector/vnf_collectors/vmware/vcd_mocks/vrops_multi.json
@@ -0,0 +1,251 @@
+{
+	"values": [
+		{
+			"resourceId": "a761f4ae-40a3-4696-ae37-ee447ed421c3",
+			"stat-list": {
+				"stat": [
+					{
+						"data": [
+							0.0,
+							0.0,
+							0.0,
+							0.0
+						],
+						"intervalUnit": {
+							"quantifier": 1
+						},
+						"statKey": {
+							"key": "virtualDisk:aggregate of all instances|totalReadLatency_average"
+						},
+						"timestamps": [
+							1561744712552,
+							1561744772549,
+							1561744832548,
+							1561744892557
+						]
+					},
+					{
+						"data": [
+							1.1373332738876343,
+							1.1440000534057617,
+							1.1239999532699585,
+							100.0
+						],
+						"intervalUnit": {
+							"quantifier": 1
+						},
+						"statKey": {
+							"key": "cpu|usage_average"
+						},
+						"timestamps": [
+							1561744712552,
+							1561744772549,
+							1561744832548,
+							1561744892557
+						]
+					},
+					{
+						"data": [
+							6.0,
+							6.066666603088379,
+							6.133333206176758,
+							6.066666603088379
+						],
+						"intervalUnit": {
+							"quantifier": 1
+						},
+						"statKey": {
+							"key": "virtualDisk:aggregate of all instances|numberWriteAveraged_average"
+						},
+						"timestamps": [
+							1561744712552,
+							1561744772549,
+							1561744832548,
+							1561744892557
+						]
+					},
+					{
+						"data": [
+							0.0,
+							0.0,
+							0.0,
+							0.0
+						],
+						"intervalUnit": {
+							"quantifier": 1
+						},
+						"statKey": {
+							"key": "virtualDisk:aggregate of all instances|numberReadAveraged_average"
+						},
+						"timestamps": [
+							1561744712552,
+							1561744772549,
+							1561744832548,
+							1561744892557
+						]
+					},
+					{
+						"data": [
+							0.0,
+							0.0,
+							0.0,
+							0.0
+						],
+						"intervalUnit": {
+							"quantifier": 1
+						},
+						"statKey": {
+							"key": "net|droppedTx_summation"
+						},
+						"timestamps": [
+							1561744712552,
+							1561744772549,
+							1561744832548,
+							1561744892557
+						]
+					},
+					{
+						"data": [
+							0.20000000298023224,
+							0.20000000298023224,
+							0.20000000298023224,
+							10.0
+						],
+						"intervalUnit": {
+							"quantifier": 1
+						},
+						"statKey": {
+							"key": "virtualDisk|read_average"
+						},
+						"timestamps": [
+							1561744712552,
+							1561744772549,
+							1561744832548,
+							1561744892557
+						]
+					},
+					{
+						"data": [
+							0.0,
+							0.0,
+							0.0,
+							0.0
+						],
+						"intervalUnit": {
+							"quantifier": 1
+						},
+						"statKey": {
+							"key": "net|transmitted_average"
+						},
+						"timestamps": [
+							1561744712552,
+							1561744772549,
+							1561744832548,
+							1561744892557
+						]
+					},
+					{
+						"data": [
+							20.491540908813477,
+							20.505388259887695,
+							20.517423629760742,
+							20.515941619873047
+						],
+						"intervalUnit": {
+							"quantifier": 1
+						},
+						"statKey": {
+							"key": "mem|usage_average"
+						},
+						"timestamps": [
+							1561744712552,
+							1561744772549,
+							1561744832548,
+							1561744892557
+						]
+					},
+					{
+						"data": [
+							0.0,
+							0.0,
+							0.0,
+							0.0
+						],
+						"intervalUnit": {
+							"quantifier": 1
+						},
+						"statKey": {
+							"key": "virtualDisk:aggregate of all instances|totalWriteLatency_average"
+						},
+						"timestamps": [
+							1561744712552,
+							1561744772549,
+							1561744832548,
+							1561744892557
+						]
+					},
+					{
+						"data": [
+							46.266666412353516,
+							46.599998474121094,
+							46.93333435058594,
+							46.86666488647461
+						],
+						"intervalUnit": {
+							"quantifier": 1
+						},
+						"statKey": {
+							"key": "virtualDisk|write_average"
+						},
+						"timestamps": [
+							1561744712552,
+							1561744772549,
+							1561744832548,
+							1561744892557
+						]
+					},
+					{
+						"data": [
+							0.0,
+							0.0,
+							0.0,
+							0.0
+						],
+						"intervalUnit": {
+							"quantifier": 1
+						},
+						"statKey": {
+							"key": "net|received_average"
+						},
+						"timestamps": [
+							1561744712552,
+							1561744772549,
+							1561744832548,
+							1561744892557
+						]
+					},
+					{
+						"data": [
+							0.0,
+							0.0,
+							0.0,
+							0.0
+						],
+						"intervalUnit": {
+							"quantifier": 1
+						},
+						"statKey": {
+							"key": "net:vmnic5|transmitted_average"
+						},
+						"timestamps": [
+							1561744712552,
+							1561744772549,
+							1561744832548,
+							1561744892557
+						]
+					}
+				]
+			}
+		}
+	]
+}
diff --git a/test-requirements.txt b/test-requirements.txt
index b404738..c67a4b1 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -21,3 +21,4 @@
 ##
 flake8<3.0
 mock
+requests-mock
diff --git a/tox.ini b/tox.ini
index 898e487..3a360af 100644
--- a/tox.ini
+++ b/tox.ini
@@ -37,6 +37,7 @@
 [testenv:pylint]
 basepython = python3
 deps = pylint
+       -r{toxinidir}/test-requirements.txt
 commands =
     pylint -E osm_mon