diff --git a/tests/test_usb2_endpoints.py b/tests/test_usb2_endpoints.py
new file mode 100644
index 00000000..7262c764
--- /dev/null
+++ b/tests/test_usb2_endpoints.py
@@ -0,0 +1,226 @@
+#
+# This file is part of LUNA.
+#
+# Copyright (c) 2025 Great Scott Gadgets <info@greatscottgadgets.com>
+# SPDX-License-Identifier: BSD-3-Clause
+
+from luna.gateware.test  import (
+    LunaUSBGatewareTestCase,
+    LunaSSGatewareTestCase,
+    ss_domain_test_case,
+    usb_domain_test_case,
+)
+
+from luna.usb2           import (
+    USBIsochronousStreamInEndpoint,
+    USBIsochronousStreamOutEndpoint,
+)
+
+
+MAX_PACKET_SIZE = 512
+
+class USBIsochronousStreamInEndpointTest(LunaUSBGatewareTestCase):
+    FRAGMENT_UNDER_TEST = USBIsochronousStreamInEndpoint
+    FRAGMENT_ARGUMENTS  = {'endpoint_number': 1, 'max_packet_size': MAX_PACKET_SIZE}
+
+    def initialize_signals(self):
+        # Configure the endpoint.
+        yield self.dut.bytes_in_frame.eq(MAX_PACKET_SIZE)
+
+        # Pretend that our host is always targeting our endpoint.
+        yield self.dut.interface.tokenizer.endpoint.eq(self.dut._endpoint_number)
+        yield self.dut.interface.tokenizer.is_in.eq(1)
+
+    @usb_domain_test_case
+    def test_single_packet_in(self):
+        dut = self.dut
+
+        producer = dut.stream
+        consumer = dut.interface.tx
+        data     = [b % 0xff for b in range(1, MAX_PACKET_SIZE + 1)]
+        sent     = []
+
+        # Before we see any data, our streams should all be invalid
+        self.assertEqual((yield consumer.first), 0)
+        self.assertEqual((yield consumer.last), 0)
+        self.assertEqual((yield consumer.payload), 0)
+        self.assertEqual((yield consumer.ready), 0)
+        self.assertEqual((yield consumer.valid), 0)
+        self.assertEqual((yield producer.payload), 0)
+        self.assertEqual((yield producer.ready), 0)
+        self.assertEqual((yield producer.valid), 0)
+
+        # Once we start a new frame ...
+        yield dut.interface.tokenizer.new_frame.eq(1)
+        yield
+
+        # ... but the host hasn't yet requested data from our endpoint;
+        # our stream should still be at rest.
+        self.assertEqual((yield consumer.first), 0)
+        self.assertEqual((yield dut.data_requested), 0)
+
+        # When the host requests data ...
+        yield dut.interface.tokenizer.ready_for_response.eq(1)
+        yield
+
+        # ... we go out of State(IDLE) and can check that data_requested is strobed.
+        self.assertEqual((yield dut.data_requested), 1)
+
+        # Then one cycle later...
+        yield
+
+        # ... we will be in State(SEND_DATA) and our consumer stream becomes valid.
+        self.assertEqual((yield consumer.first), 1)
+        self.assertEqual((yield consumer.last), 0)
+        self.assertEqual((yield consumer.valid), 1)
+
+        # Once the producer has data available ...
+        yield producer.valid.eq(1)
+        yield producer.payload.eq(data[0])
+
+        # ... but we haven't advanced yet ...
+        self.assertEqual((yield producer.ready), 0)
+        self.assertEqual((yield consumer.ready), 0)
+        self.assertEqual((yield consumer.payload), 0x00)
+
+        # ... until our data is accepted.
+        yield consumer.ready.eq(1)
+        yield
+        sent.append((yield consumer.payload))
+
+        # Now we can chack that the transmitter has the first byte ...
+        self.assertEqual((yield producer.ready), 1)
+        self.assertEqual((yield consumer.payload), data[0])
+        self.assertEqual((yield consumer.first), 1)
+
+        # ... before sending the rest of the packet.
+        clocks = 0
+        for byte in data[1:]:
+            clocks += 1
+            yield producer.payload.eq(byte)
+            yield
+            sent.append((yield consumer.payload))
+            self.assertEqual((yield consumer.payload), byte)
+
+        # Finally, we can check that we have received the correct
+        # amount of data and that this was the last byte.
+        self.assertEqual(sent, data)
+        self.assertEqual((yield consumer.last), 1)
+        self.assertEqual(clocks, len(data) - 1)
+
+
+class USBIsochronousStreamOutEndpointTest(LunaUSBGatewareTestCase):
+    FRAGMENT_UNDER_TEST = USBIsochronousStreamOutEndpoint
+    FRAGMENT_ARGUMENTS  = {'endpoint_number': 1, 'max_packet_size': MAX_PACKET_SIZE}
+
+    def initialize_signals(self):
+        # Pretend that our host is always targeting our endpoint.
+        yield self.dut.interface.tokenizer.endpoint.eq(self.dut._endpoint_number)
+        yield self.dut.interface.tokenizer.is_out.eq(1)
+
+
+    @usb_domain_test_case
+    def test_single_packet_out(self):
+        dut = self.dut
+
+        producer = dut.interface.rx
+        consumer = dut.stream
+        data     = [b % 0xff for b in range(1, MAX_PACKET_SIZE + 1)]
+        received = []
+
+        # Before we see any data, our streams should all be invalid.
+        self.assertEqual((yield consumer.p.data), 0)
+        self.assertEqual((yield consumer.p.first), 0)
+        self.assertEqual((yield consumer.p.last), 0)
+        self.assertEqual((yield consumer.ready), 0)
+        self.assertEqual((yield consumer.valid), 0)
+        self.assertEqual((yield producer.next), 0)
+        self.assertEqual((yield producer.payload), 0)
+        self.assertEqual((yield producer.valid), 0)
+
+        # Once the producer sends the first byte ...
+        yield producer.valid.eq(1)
+        yield producer.next.eq(1)
+        yield producer.payload.eq(data[0])
+        yield
+
+        # ... and only the first byte ...
+        yield producer.next.eq(0)
+        yield
+
+        # ... we shouldn't see anything in the consumer stream ...
+        self.assertEqual((yield consumer.p.first), 0)
+        self.assertEqual((yield consumer.p.last), 0)
+        self.assertEqual((yield consumer.p.data), 0)
+
+        # ... but even if we were to mark the consumer's stream as ready ...
+        yield consumer.ready.eq(1)
+        yield
+
+        # ... the consumer stream will still not be valid because
+        # we're using a TransactionalizedFIFO that will only commit
+        # once the entire packet has been received.
+        self.assertEqual((yield consumer.valid), 0)
+        self.assertEqual((yield consumer.p.first), 0)
+        self.assertEqual((yield consumer.p.last), 0)
+        self.assertEqual((yield consumer.p.data), 0)
+
+        # So let's send the rest of the packet ...
+        yield producer.next.eq(1)
+        clocks = 0
+        for byte in data[1:]:
+            clocks += 1
+            yield producer.payload.eq(byte)
+            yield
+
+        # ... which should have taken len(data) - 1 cycles because we already sent the first byte.
+        self.assertEqual(clocks, len(data) - 1)
+        self.assertEqual((yield producer.payload), data[-1])
+
+        # By now the consumer stream would also have picked up the first byte ...
+        self.assertEqual((yield consumer.valid), 0)
+        self.assertEqual((yield consumer.p.first), 1)
+        self.assertEqual((yield consumer.p.data), data[0])
+
+        # ... but the stream still won't advance ...
+        yield
+        self.assertEqual((yield consumer.valid), 0)
+        self.assertEqual((yield consumer.p.first), 1)
+        self.assertEqual((yield consumer.p.data), data[0])
+
+        # ... until we finally mark the packet as complete and invalidate the producer stream.
+        yield dut.interface.rx_complete.eq(1)
+        yield producer.valid.eq(0)
+        yield producer.next.eq(0)
+        yield
+
+        # After three clock cycles delay our stream goes finally valid ...
+        yield
+        yield
+        yield
+        self.assertEqual((yield consumer.valid), 1)
+
+        # ... and we can now receive the packet.
+        clocks = 0
+        while (yield consumer.valid) and (yield consumer.p.last) == 0:
+            clocks += 1
+            received.append((yield consumer.p.data))
+            yield
+
+        self.assertEqual(received, data)
+        self.assertEqual((yield consumer.p.last), 1)
+        self.assertEqual((yield consumer.p.data), data[-1])
+        self.assertEqual(clocks, len(data))
+
+        # Finally, let's invalidate the consumer ...
+        yield consumer.ready.eq(0)
+        yield
+
+        # ... and everything should be over.
+        self.assertEqual((yield producer.valid), 0)
+        self.assertEqual((yield producer.next), 0)
+        self.assertEqual((yield consumer.ready), 0)
+        self.assertEqual((yield consumer.valid), 0)
+        self.assertEqual((yield consumer.p.first), 0)
+        self.assertEqual((yield consumer.p.last), 0)
+        self.assertEqual((yield consumer.p.data), 0)