diff --git a/ponsim/test_ponsim.py b/ponsim/test_ponsim.py
new file mode 100644
index 0000000..365468b
--- /dev/null
+++ b/ponsim/test_ponsim.py
@@ -0,0 +1,372 @@
+#
+# Copyright 2016 the original author or authors.
+#
+# 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.
+#
+
+from unittest import TestCase, main
+
+from scapy.layers.inet import IP
+from scapy.layers.l2 import Ether, Dot1Q, EAPOL
+
+from ponsim import PonSim
+from voltha.extensions.IGMP import IGMP_TYPE_V3_MEMBERSHIP_REPORT, IGMPv3gr, \
+    IGMPv3, IGMP_TYPE_MEMBERSHIP_QUERY
+from voltha.extensions.IGMP import IGMP_V3_GR_TYPE_EXCLUDE
+from voltha.protos import third_party
+from voltha.core.flow_decomposer import *
+_ = third_party
+
+
+class TestPonSim(TestCase):
+
+    def setUp(self):
+        self.output = []
+        self.pon = PonSim(onus=2, egress_fun=lambda port, frame:
+            self.output.append((port, frame)))
+
+    def reset_output(self):
+        while self.output:
+            self.output.pop()
+
+    def ingress_frame(self, frame, ports=None):
+        if ports is None:
+            ports = self.pon.get_ports()
+        if isinstance(ports, int):
+            ports = [ports]
+        for port in ports:
+            self.pon.ingress(port, frame)
+
+    def assert_dont_pass(self, frame, ports=None):
+        self.reset_output()
+        self.ingress_frame(frame, ports)
+        self.assertEqual(self.output, [])
+
+    def assert_untagged_frames_dont_pass(self, ports=None):
+        self.assert_dont_pass(Ether(), ports=ports)
+
+    def test_basics(self):
+        self.assertEqual(self.pon.get_ports(), [0, 128, 129])
+
+    def test_by_default_no_traffic_passes(self):
+        self.assert_untagged_frames_dont_pass()
+
+    def test_downstream_unicast_forwarding(self):
+
+        self.pon.olt_install_flows([
+            mk_flow_stat(
+                match_fields=[in_port(2), vlan_vid(4096 + 1000)],
+                actions=[pop_vlan(), output(1)]
+            )
+        ])
+        self.pon.onu_install_flows(128, [
+            mk_flow_stat(
+                match_fields=[in_port(1), vlan_vid(4096 + 128)],
+                actions=[set_field(vlan_vid(4096 + 0)), output(2)]
+            )
+        ])
+
+        # untagged frames shall not get through
+        self.assert_untagged_frames_dont_pass()
+
+        # incorrect single- or double-tagged frames don't pass
+        self.assert_dont_pass(Ether() / Dot1Q(vlan=1000) / IP())
+        self.assert_dont_pass(Ether() / Dot1Q(vlan=128) / IP())
+        self.assert_dont_pass(
+            Ether() / Dot1Q(vlan=128) / Dot1Q(vlan=1000) / IP())
+        self.assert_dont_pass(
+            Ether() / Dot1Q(vlan=1000) / Dot1Q(vlan=129) / IP())
+
+        # properly tagged downstream frame gets through and pops up at port 128
+        # as untagged
+        kw = dict(src='00:00:00:11:11:11', dst='00:00:00:22:22:22')
+        in_frame = Ether(**kw) / Dot1Q(vlan=1000) / Dot1Q(vlan=128) / IP()
+        out_frame = Ether(**kw) / Dot1Q(vlan=0) / IP()
+
+        self.ingress_frame(in_frame)
+        self.assertEqual(self.output, [(128, out_frame)])
+
+    def test_upstream_unicast_forwarding(self):
+
+        self.pon.onu_install_flows(128, [
+            mk_flow_stat(
+                match_fields=[in_port(2), vlan_vid(4096 + 0)],
+                actions=[set_field(vlan_vid(4096 + 128)), output(1)]
+            )
+        ])
+        self.pon.olt_install_flows([
+            mk_flow_stat(
+                match_fields=[in_port(1), vlan_vid(4096 + 128)],
+                actions=[push_vlan(0x8100), set_field(vlan_vid(4096 + 1000)),
+                         output(2)]
+            )
+        ])
+
+        # untagged frames shall not get through
+        self.assert_untagged_frames_dont_pass()
+
+        # incorrect single- or double-tagged frames don't pass
+        self.assert_dont_pass(Ether() / Dot1Q(vlan=1000) / IP())
+        self.assert_dont_pass(Ether() / Dot1Q(vlan=128) / IP())
+        self.assert_dont_pass(
+            Ether() / Dot1Q(vlan=1000) / Dot1Q(vlan=128) / IP())
+        self.assert_dont_pass(
+            Ether() / Dot1Q(vlan=129) / Dot1Q(vlan=1000) / IP())
+
+        # properly tagged downstream frame gets through and pops up at port 128
+        # as untagged
+        kw = dict(src='00:00:00:11:11:11', dst='00:00:00:22:22:22')
+        in_frame = Ether(**kw) / Dot1Q(vlan=0) / IP()
+        out_frame = Ether(**kw) / Dot1Q(vlan=1000) / Dot1Q(vlan=128) / IP()
+
+        self.ingress_frame(in_frame)
+        self.assertEqual(self.output, [(0, out_frame)])
+
+
+    def setup_all_flows(self):
+
+        self.pon.olt_install_flows([
+            mk_flow_stat(
+                priority=2000,
+                match_fields=[in_port(2), vlan_vid(4096 + 4000), vlan_pcp(0)],
+                actions=[pop_vlan(), output(1)]
+            ),
+            mk_flow_stat(
+                priority=2000,
+                match_fields=[in_port(1), eth_type(0x888e)],
+                actions=[push_vlan(0x8100), set_field(vlan_vid(4096 + 4000)),
+                         output(2)]
+            ),
+            mk_flow_stat(
+                priority=1000,
+                match_fields=[in_port(1), eth_type(0x800), ip_proto(2)],
+                actions=[push_vlan(0x8100), set_field(vlan_vid(4096 + 4000)),
+                         output(2)]
+            ),
+            mk_flow_stat(
+                priority=1000,
+                match_fields=[in_port(1), eth_type(0x800), ip_proto(17),
+                              udp_dst(67)],
+                actions=[push_vlan(0x8100), set_field(vlan_vid(4096 + 4000)),
+                         output(2)]
+            ),
+            mk_flow_stat(
+                priority=1000,
+                match_fields=[in_port(2), vlan_vid(4096 + 140)],
+                actions=[pop_vlan(), output(1)]
+            ),
+            mk_flow_stat(
+                priority=500,
+                match_fields=[in_port(2), vlan_vid(4096 + 1000)],
+                actions=[pop_vlan(), output(1)]
+            ),
+            mk_flow_stat(
+                priority=500,
+                match_fields=[in_port(1), vlan_vid(4096 + 128)],
+                actions=[
+                    push_vlan(0x8100), set_field(vlan_vid(4096 + 1000)),
+                    output(2)]
+            ),
+            mk_flow_stat(
+                priority=500,
+                match_fields=[in_port(1), vlan_vid(4096 + 129)],
+                actions=[
+                    push_vlan(0x8100), set_field(vlan_vid(4096 + 1000)),
+                    output(2)]
+            ),
+        ])
+
+        self.pon.onu_install_flows(128, [
+            mk_flow_stat(
+                priority=500,
+                match_fields=[in_port(2), vlan_vid(4096 + 0)],
+                actions=[
+                    set_field(vlan_vid(4096 + 128)), output(1)]
+            ),
+            mk_flow_stat(
+                priority=1000,
+                match_fields=[
+                    in_port(1), eth_type(0x800), ipv4_dst(0xe4010102)],
+                actions=[output(2)]
+            ),
+            mk_flow_stat(
+                priority=1000,
+                match_fields=[
+                    in_port(1), eth_type(0x800), ipv4_dst(0xe4010104)],
+                actions=[output(2)]
+            ),
+            mk_flow_stat(
+                priority=500,
+                match_fields=[in_port(1), vlan_vid(4096 + 128)],
+                actions=[set_field(vlan_vid(4096 + 0)), output(2)]
+            ),
+            mk_flow_stat(
+                priority=500,
+                match_fields=[in_port(2), vlan_vid(0)],
+                actions=[push_vlan(0x8100), set_field(vlan_vid(4096 + 128)),
+                         output(1)]
+            )
+        ])
+
+        self.pon.onu_install_flows(129, [
+            mk_flow_stat(
+                priority=500,
+                match_fields=[in_port(2), vlan_vid(4096 + 0)],
+                actions=[
+                    set_field(vlan_vid(4096 + 129)), output(1)]
+            ),
+            mk_flow_stat(
+                priority=1000,
+                match_fields=[
+                    in_port(1), eth_type(0x800), ipv4_dst(0xe4010103)],
+                actions=[output(2)]
+            ),
+            mk_flow_stat(
+                priority=1000,
+                match_fields=[
+                    in_port(1), eth_type(0x800), ipv4_dst(0xe4010104)],
+                actions=[output(2)]
+            ),
+            mk_flow_stat(
+                priority=500,
+                match_fields=[in_port(1), vlan_vid(4096 + 129)],
+                actions=[set_field(vlan_vid(4096 + 0)), output(2)]
+            ),
+            mk_flow_stat(
+                priority=500,
+                match_fields=[in_port(2), vlan_vid(0)],
+                actions=[push_vlan(0x8100), set_field(vlan_vid(4096 + 129)),
+                         output(1)]
+            )
+        ])
+
+    def test_combo_block_untagged_downstream(self):
+        self.setup_all_flows()
+        self.assert_untagged_frames_dont_pass(ports=0)
+
+    def test_eapol_in(self):
+        self.setup_all_flows()
+        kw = dict(src='00:00:00:11:11:11', dst='00:00:00:22:22:22')
+        in_frame = Ether(**kw) / EAPOL(type=1)
+        out_frame1 = Ether(**kw) / Dot1Q(vlan=4000) / Dot1Q(vlan=128) / EAPOL(type=1)
+        out_frame2 = Ether(**kw) / Dot1Q(vlan=4000) / Dot1Q(vlan=129) / EAPOL(type=1)
+        self.ingress_frame(in_frame)
+        self.assertEqual(self.output, [(0, out_frame1), (0, out_frame2)])
+
+    def test_eapol_out(self):
+        self.setup_all_flows()
+        kw = dict(src='00:00:00:11:11:11', dst='00:00:00:22:22:22')
+        in_frame1 = Ether(**kw) / Dot1Q(vlan=4000) / Dot1Q(vlan=128) / EAPOL(type=1)
+        in_frame2 = Ether(**kw) / Dot1Q(vlan=4000) / Dot1Q(vlan=129) / EAPOL(type=1)
+        out_frame = Ether(**kw) / Dot1Q(vlan=0) / EAPOL(type=1)
+        self.ingress_frame(in_frame1)
+        self.ingress_frame(in_frame2)
+        self.assertEqual(self.output, [(128, out_frame), (129, out_frame)])
+
+    def test_igmp_in(self):
+        self.setup_all_flows()
+        kw = dict(src='00:00:00:11:11:11', dst='00:00:00:22:22:22')
+        mr = IGMPv3(type=IGMP_TYPE_V3_MEMBERSHIP_REPORT, max_resp_code=30,
+                    gaddr="224.0.0.1")
+        mr.grps = [
+            IGMPv3gr(rtype=IGMP_V3_GR_TYPE_EXCLUDE, mcaddr="228.1.1.3")]
+
+        in_frame = Ether(**kw) / IP() / mr
+        out_frame1 = Ether(**kw) / Dot1Q(vlan=4000) / Dot1Q(vlan=128) /\
+                     in_frame.payload.copy()
+        out_frame2 = Ether(**kw) / Dot1Q(vlan=4000) / Dot1Q(vlan=129) /\
+                     in_frame.payload.copy()
+        self.ingress_frame(in_frame)
+        self.assertEqual(self.output, [(0, out_frame1), (0, out_frame2)])
+
+    def test_igmp_out(self):
+        self.setup_all_flows()
+        kw = dict(src='00:00:00:11:11:11', dst='00:00:00:22:22:22')
+        mq = IGMPv3(type=IGMP_TYPE_MEMBERSHIP_QUERY, max_resp_code=120)
+        in_frame1 = Ether(**kw) / Dot1Q(vlan=4000) / Dot1Q(vlan=128) /\
+                    IP() / mq.copy()
+        in_frame2 = Ether(**kw) / Dot1Q(vlan=4000) / Dot1Q(vlan=129) /\
+                    IP() / mq.copy()
+        out_frame = Ether(**kw) / Dot1Q(vlan=0) / IP() / mq.copy()
+        self.ingress_frame(in_frame1)
+        self.ingress_frame(in_frame2)
+        self.assertEqual(self.output, [(128, out_frame), (129, out_frame)])
+
+    def test_combo_downstream_unicast_onu1(self):
+        self.setup_all_flows()
+        kw = dict(src='00:00:00:11:11:11', dst='00:00:00:22:22:22')
+        in_frame = Ether(**kw) / Dot1Q(vlan=1000) / Dot1Q(vlan=128) / IP()
+        out_frame = Ether(**kw) / Dot1Q(vlan=0) / IP()
+        self.reset_output()
+        self.ingress_frame(in_frame, ports=0)
+        self.assertEqual(self.output, [(128, out_frame)])
+
+    def test_combo_downstream_unicast_onu2(self):
+        self.setup_all_flows()
+        kw = dict(src='00:00:00:11:11:11', dst='00:00:00:22:22:22')
+        in_frame = Ether(**kw) / Dot1Q(vlan=1000) / Dot1Q(vlan=129) / IP()
+        out_frame = Ether(**kw) / Dot1Q(vlan=0) / IP()
+        self.reset_output()
+        self.ingress_frame(in_frame, ports=0)
+        self.assertEqual(self.output, [(129, out_frame)])
+
+    def test_combo_upstream_unicast_onu1(self):
+        self.setup_all_flows()
+        kw = dict(src='00:00:00:11:11:11', dst='00:00:00:22:22:22')
+        in_frame = Ether(**kw) / Dot1Q(vlan=1000) / Dot1Q(vlan=128) / IP()
+        out_frame = Ether(**kw) / Dot1Q(vlan=0) / IP()
+        self.ingress_frame(in_frame)
+        self.assertEqual(self.output, [(128, out_frame)])
+
+    def test_combo_upstream_unicast_onu2(self):
+        self.setup_all_flows()
+        kw = dict(src='00:00:00:11:11:11', dst='00:00:00:22:22:22')
+        in_frame = Ether(**kw) / Dot1Q(vlan=1000) / Dot1Q(vlan=129) / IP()
+        out_frame = Ether(**kw) / Dot1Q(vlan=0) / IP()
+        self.ingress_frame(in_frame)
+        self.assertEqual(self.output, [(129, out_frame)])
+
+    def test_combo_multicast_stream1(self):
+        self.setup_all_flows()
+        kw = dict(src='00:00:00:11:11:11', dst='00:00:00:22:22:22')
+        in_frame = Ether(**kw) / Dot1Q(vlan=140) / IP(dst='228.1.1.1')
+        self.ingress_frame(in_frame)
+        self.assertEqual(self.output, [])
+
+    def test_combo_multicast_stream2(self):
+        self.setup_all_flows()
+        kw = dict(src='00:00:00:11:11:11', dst='00:00:00:22:22:22')
+        in_frame = Ether(**kw) / Dot1Q(vlan=140) / IP(dst='228.1.1.2')
+        out_frame = Ether(**kw) / IP(dst='228.1.1.2')
+        self.ingress_frame(in_frame)
+        self.assertEqual(self.output, [(128, out_frame),])
+
+    def test_combo_multicast_stream3(self):
+        self.setup_all_flows()
+        kw = dict(src='00:00:00:11:11:11', dst='00:00:00:22:22:22')
+        in_frame = Ether(**kw) / Dot1Q(vlan=140) / IP(dst='228.1.1.3')
+        out_frame = Ether(**kw) / IP(dst='228.1.1.3')
+        self.ingress_frame(in_frame)
+        self.assertEqual(self.output, [(129, out_frame),])
+
+    def test_combo_multicast_stream4(self):
+        self.setup_all_flows()
+        kw = dict(src='00:00:00:11:11:11', dst='00:00:00:22:22:22')
+        in_frame = Ether(**kw) / Dot1Q(vlan=140) / IP(dst='228.1.1.4')
+        out_frame = Ether(**kw) / IP(dst='228.1.1.4')
+        self.ingress_frame(in_frame)
+        self.assertEqual(self.output, [(128, out_frame), (129, out_frame)])
+
+
+if __name__ == '__main__':
+    main()