diff --git a/common/tests/metrics_tests.py b/common/tests/metrics_tests.py
new file mode 100644
index 0000000..f48f2f8
--- /dev/null
+++ b/common/tests/metrics_tests.py
@@ -0,0 +1,241 @@
+"""
+Copyright 2020 The Magma Authors.
+
+This source code is licensed under the BSD-style license found in the
+LICENSE file in the root directory of this source tree.
+
+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.
+"""
+
+import unittest
+import unittest.mock
+
+import metrics_pb2
+from common import metrics_export
+from orc8r.protos import metricsd_pb2
+from prometheus_client import (
+    CollectorRegistry,
+    Counter,
+    Gauge,
+    Histogram,
+    Summary,
+)
+
+
+class Service303MetricTests(unittest.TestCase):
+    """
+    Tests for the Service303 metrics interface
+    """
+
+    def setUp(self):
+        self.registry = CollectorRegistry()
+        self.maxDiff = None
+
+    def test_counter(self):
+        """Test that we can track counters in Service303"""
+        # Add a counter with a label to the regisry
+        c = Counter(
+            'process_max_fds', 'A counter', ['result'],
+            registry=self.registry,
+        )
+
+        # Create two series for value1 and value2
+        c.labels('success').inc(1.23)
+        c.labels('failure').inc(2.34)
+
+        # Build proto outputs
+        counter1 = metrics_pb2.Counter(value=1.23)
+        counter2 = metrics_pb2.Counter(value=2.34)
+        metric1 = metrics_pb2.Metric(
+            counter=counter1,
+            timestamp_ms=1234000,
+        )
+        metric2 = metrics_pb2.Metric(
+            counter=counter2,
+            timestamp_ms=1234000,
+        )
+        family = metrics_pb2.MetricFamily(
+            name=str(metricsd_pb2.process_max_fds),
+            type=metrics_pb2.COUNTER,
+        )
+        metric1.label.add(
+            name=str(metricsd_pb2.result),
+            value='success',
+        )
+        metric2.label.add(
+            name=str(metricsd_pb2.result),
+            value='failure',
+        )
+        family.metric.extend([metric1, metric2])
+
+        with unittest.mock.patch('time.time') as mock_time:
+            mock_time.side_effect = lambda: 1234
+            self.assertCountEqual(
+                list(metrics_export.get_metrics(self.registry))[0].metric,
+                family.metric,
+            )
+
+    def test_gauge(self):
+        """Test that we can track gauges in Service303"""
+        # Add a gauge with a label to the regisry
+        c = Gauge(
+            'process_max_fds', 'A gauge', ['result'],
+            registry=self.registry,
+        )
+
+        # Create two series for value1 and value2
+        c.labels('success').inc(1.23)
+        c.labels('failure').inc(2.34)
+
+        # Build proto outputs
+        gauge1 = metrics_pb2.Gauge(value=1.23)
+        gauge2 = metrics_pb2.Gauge(value=2.34)
+        metric1 = metrics_pb2.Metric(
+            gauge=gauge1,
+            timestamp_ms=1234000,
+        )
+        metric2 = metrics_pb2.Metric(
+            gauge=gauge2,
+            timestamp_ms=1234000,
+        )
+        family = metrics_pb2.MetricFamily(
+            name=str(metricsd_pb2.process_max_fds),
+            type=metrics_pb2.GAUGE,
+        )
+        metric1.label.add(
+            name=str(metricsd_pb2.result),
+            value='success',
+        )
+        metric2.label.add(
+            name=str(metricsd_pb2.result),
+            value='failure',
+        )
+        family.metric.extend([metric1, metric2])
+
+        with unittest.mock.patch('time.time') as mock_time:
+            mock_time.side_effect = lambda: 1234
+            self.assertCountEqual(
+                list(metrics_export.get_metrics(self.registry))[0].metric,
+                family.metric,
+            )
+
+    def test_summary(self):
+        """Test that we can track summaries in Service303"""
+        # Add a summary with a label to the regisry
+        c = Summary(
+            'process_max_fds', 'A summary', [
+            'result',
+            ], registry=self.registry,
+        )
+        c.labels('success').observe(1.23)
+        c.labels('failure').observe(2.34)
+
+        # Build proto outputs
+        summary1 = metrics_pb2.Summary(sample_count=1, sample_sum=1.23)
+        summary2 = metrics_pb2.Summary(sample_count=1, sample_sum=2.34)
+        metric1 = metrics_pb2.Metric(
+            summary=summary1,
+            timestamp_ms=1234000,
+        )
+        metric2 = metrics_pb2.Metric(
+            summary=summary2,
+            timestamp_ms=1234000,
+        )
+        family = metrics_pb2.MetricFamily(
+            name=str(metricsd_pb2.process_max_fds),
+            type=metrics_pb2.SUMMARY,
+        )
+        metric1.label.add(
+            name=str(metricsd_pb2.result),
+            value='success',
+        )
+        metric2.label.add(
+            name=str(metricsd_pb2.result),
+            value='failure',
+        )
+        family.metric.extend([metric1, metric2])
+
+        with unittest.mock.patch('time.time') as mock_time:
+            mock_time.side_effect = lambda: 1234
+            self.assertCountEqual(
+                list(metrics_export.get_metrics(self.registry))[0].metric,
+                family.metric,
+            )
+
+    def test_histogram(self):
+        """Test that we can track histogram in Service303"""
+        # Add a histogram with a label to the regisry
+        c = Histogram(
+            'process_max_fds', 'A summary', ['result'],
+            registry=self.registry, buckets=[0, 2, float('inf')],
+        )
+        c.labels('success').observe(1.23)
+        c.labels('failure').observe(2.34)
+
+        # Build proto outputs
+        histogram1 = metrics_pb2.Histogram(sample_count=1, sample_sum=1.23)
+        histogram1.bucket.add(upper_bound=0, cumulative_count=0)
+        histogram1.bucket.add(upper_bound=2, cumulative_count=1)
+        histogram1.bucket.add(upper_bound=float('inf'), cumulative_count=1)
+        histogram2 = metrics_pb2.Histogram(sample_count=1, sample_sum=2.34)
+        histogram2.bucket.add(upper_bound=0, cumulative_count=0)
+        histogram2.bucket.add(upper_bound=2, cumulative_count=0)
+        histogram2.bucket.add(upper_bound=float('inf'), cumulative_count=1)
+        metric1 = metrics_pb2.Metric(
+            histogram=histogram1,
+            timestamp_ms=1234000,
+        )
+        metric2 = metrics_pb2.Metric(
+            histogram=histogram2,
+            timestamp_ms=1234000,
+        )
+        family = metrics_pb2.MetricFamily(
+            name=str(metricsd_pb2.process_max_fds),
+            type=metrics_pb2.HISTOGRAM,
+        )
+        metric1.label.add(
+            name=str(metricsd_pb2.result),
+            value='success',
+        )
+        metric2.label.add(
+            name=str(metricsd_pb2.result),
+            value='failure',
+        )
+        family.metric.extend([metric1, metric2])
+
+        with unittest.mock.patch('time.time') as mock_time:
+            mock_time.side_effect = lambda: 1234
+            self.assertCountEqual(
+                list(metrics_export.get_metrics(self.registry))[0].metric,
+                family.metric,
+            )
+
+    def test_converted_enums(self):
+        """ Test that metric names and labels are auto converted """
+        # enum values (from metricsd.proto):
+        # mme_new_association => 500, result => 0
+        c = Counter(
+            'mme_new_association', 'A counter', ['result'],
+            registry=self.registry,
+        )
+
+        c.labels('success').inc(1.23)
+
+        metric_family = list(metrics_export.get_metrics(self.registry))[0]
+
+        self.assertEqual(
+            metric_family.name,
+            str(metricsd_pb2.mme_new_association),
+        )
+        metric_labels = metric_family.metric[0].label
+        # Order not guaranteed=
+        self.assertEqual(metric_labels[0].name, str(metricsd_pb2.result))
+        self.assertEqual(metric_labels[0].value, 'success')
+
+
+if __name__ == "__main__":
+    unittest.main()