Fail on tuser[0]

sim/cocotb/tests/axis_saf.py

@@ -205,4 +205,24 @@ async def test_data_full(dut):
     # Even though we wrote another packet, the count should not have increased
     # we can also assert on the data pointer
     assert dut.dut.data_fifo_waddr == COUNT * LEN // 4
-    assert dut.dut.ctrl_fifo.u_fifo.waddr.value.integer == COUNT
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+    assert dut.dut.ctrl_fifo.u_fifo.waddr.value.integer == COUNT
+
+@cocotb.test()
+async def test_tuser_bad(dut):
+    tb = TB(dut)
+    await tb.reset()
+
+    tb.axis_sink.pause = True
+
+    LEN = 256
+
+    await tb.axis_source.send(AxiStreamFrame(bytes([0xcc for _ in range(LEN)])))
+
+    await tb.axis_source.send(AxiStreamFrame(bytes([0xcc for _ in range(LEN)]), tuser=1))
+
+    await Timer(Decimal(MCLK_PERIOD_NS * 400), units="ns")
+
+    # Make sure we only have 1 packet
+
+    assert dut.dut.data_fifo_waddr == LEN // 4
+    assert dut.dut.ctrl_fifo.u_fifo.waddr.value.integer == 1
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