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from typing import List, Optional
import pytest
from pyvisa_sim import common
@pytest.mark.parametrize(
"bits, want",
[
(0, 0b0),
(1, 0b1),
(5, 0b0001_1111),
(7, 0b0111_1111),
(8, 0b1111_1111),
(11, 0b0111_1111_1111),
],
)
def test_create_bitmask(bits, want):
got = common._create_bitmask(bits)
assert got == want
@pytest.mark.parametrize(
"data, data_bits, send_end, want",
[
(b"\x01", None, False, b"\x01"),
(b"hello world!", None, False, b"hello world!"),
# Only apply the mask
(b"\x03", 2, None, b"\x03"), # 0b0000_0011 --> 0b0000_0011
(b"\x04", 2, None, b"\x00"), # 0b0000_0100 --> 0b0000_0000
(b"\xff", 5, None, b"\x1f"), # 0b1111_1111 --> 0b0001_1111
(b"\xfe", 7, None, b"\x7e"), # 0b1111_1110 --> 0b0111_1110
(b"\xfe", 8, None, b"\xfe"), # 0b1111_1110 --> 0b1111_1110
(b"\xff", 9, None, b"\xff"), # 0b1111_1111 --> 0b1111_1111
# Always set highest bit *of data_bits* to 0
(b"\x04", 2, False, b"\x00"), # 0b0000_0100 --> 0b0000_0000
(b"\x04", 3, False, b"\x00"), # 0b0000_0100 --> 0b0000_0000
(b"\x05", 3, False, b"\x01"), # 0b0000_0101 --> 0b0000_0001
(b"\xff", 7, False, b"\x3f"), # 0b1111_1111 --> 0b0011_1111
(b"\xff", 8, False, b"\x7f"), # 0b1111_1111 --> 0b0111_1111
# Always set highest bit *of data_bits* to 1
(b"\x04", 2, True, b"\x02"), # 0b0000_0100 --> 0b0000_0010
(b"\x04", 3, True, b"\x04"), # 0b0000_0100 --> 0b0000_0100
(b"\x01", 3, True, b"\x05"), # 0b0000_0001 --> 0b0000_0101
(b"\x9f", 7, True, b"\x5f"), # 0b1001_1111 --> 0b0101_1111
(b"\x9f", 8, True, b"\x9f"), # 0b1001_1111 --> 0b1001_1111
# data_bits >8 bits act like data_bits=8, as type(data) is "bytes"
# which is limited 8 bits per character.
(b"\xff", 9, None, b"\xff"),
(b"\xff", 9, False, b"\x7f"),
(b"\xff", 9, True, b"\xff"),
# send_end=None only applies the mask everywhere and doesn't touch the
# highest bit
# 0x6d: 0b0110_1101 (m) --> 0x0d: 0b0000_1101 (\r)
# 0x5e: 0b0101_1110 (^) --> 0x0e: 0b0000_1110
# 0x25: 0b0010_0101 (%) --> 0x05: 0b0000_0101
# 0x25: 0b0010_0101 (%) --> 0x05: 0b0000_0101
(b"\x6d\x5e\x25\x25", 4, None, b"\r\x0e\x05\x05"),
# send_end=False sets highest post-mask bit to 0 for all
# 0x6d: 0b0110_1101 (m) --> 0x05: 0b0000_0101
# 0x5e: 0b0101_1110 (^) --> 0x06: 0b0000_0110
# 0x25: 0b0010_0101 (%) --> 0x05: 0b0000_0101
# 0x25: 0b0010_0101 (%) --> 0x05: 0b0000_0101
(b"\x6d\x5e\x25\x25", 4, False, b"\x05\x06\x05\x05"),
# send_end=True sets highest bit to 0 except for final byte
# 0x6d: 0b0110_1101 (m) --> 0x05: 0b0000_0101
# 0x5e: 0b0101_1110 (^) --> 0x06: 0b0000_0110
# 0x25: 0b0010_0101 (%) --> 0x05: 0b0000_0101
# 0x25: 0b0010_0101 (%) --> 0x0d: 0b0000_1101
(b"\x6d\x5e\x25\x25", 4, True, b"\x05\x06\x05\x0d"),
# 0x61: 0b0110_0001 (a) --> 0x21: 0b0010_0001 (!)
# 0xb1: 0b1011_0001 (±) --> 0x31: 0b0011_0001 (1)
(b"a\xb1", 6, None, b"\x21\x31"),
# 0x61: 0b0110_0001 (a) --> 0x01: 0b0000_0001
# 0xb1: 0b1011_0001 (±) --> 0x11: 0b0001_0001
(b"a\xb1", 6, False, b"\x01\x11"),
# 0x61: 0b0110_0001 (a) --> 0x01: 0b0000_0001
# 0xb1: 0b1011_0001 (±) --> 0x31: 0b0011_0001 (1)
(b"a\xb1", 6, True, b"\x011"),
],
)
def test_iter_bytes(
data: bytes, data_bits: Optional[int], send_end: bool, want: List[bytes]
) -> None:
got = b"".join(common.iter_bytes(data, data_bits=data_bits, send_end=send_end))
assert got == want
def test_iter_bytes_with_send_end_requires_data_bits() -> None:
with pytest.raises(ValueError):
# Need to wrap in list otherwise the iterator is never called.
list(common.iter_bytes(b"", data_bits=None, send_end=True))
def test_iter_bytes_raises_on_bad_data_bits() -> None:
with pytest.raises(ValueError):
list(common.iter_bytes(b"", data_bits=0, send_end=None))
|
