from migen import *
from buffer import Buffer


BUFFER_DEPTH=8
full_test_bytes = [0xDE, 0xAD, 0xBE, 0xEF, 0xBA, 0xD0, 0xCA, 0xFE, 0x15, 0x77]


def testbench(dut, length=10):
    # dut = Buffer(8, BUFFER_DEPTH)
    # full_test_bytes = [0xDE, 0xAD, 0xBE, 0xEF, 0xBA, 0xD0, 0xCA, 0xFE, 0x15, 0x77]

    test_data = full_test_bytes[:min(BUFFER_DEPTH, length)]

    # Initial condition, stb low
    yield dut.i_stb.eq(0)
    yield

    # Append bytes one-by-one
    for number in test_data:
        yield dut.din.eq(number)
        yield dut.i_stb.eq(1)
        yield

    # Deassert input strobe to buffers
    yield dut.i_stb.eq(0)
    yield
    
    # Receive bytes on-by-one
    for number in test_data:
        assert (yield dut.o_stb) == 1
        assert (yield dut.dout) == number
        yield dut.o_ack.eq(1)
        yield
        yield dut.o_ack.eq(0)
        yield
        yield

    yield
    yield
    assert (yield dut.o_stb) == 0


for buffer_len in range(len(full_test_bytes)):
    dut = Buffer(8, BUFFER_DEPTH)
    run_simulation(dut, testbench(dut, length=buffer_len), vcd_name="buffer.vcd")