I observe weird problems running pytest tests with pyvisa-sim backed fixture objects, in that replies remain in a read buffer despite the objects + resource managers being destroyed:
>>> import pyvisa
>>> rm = pyvisa.ResourceManager(visa_library='@sim')
>>> instr = rm.open_resource('ASRL2::INSTR')
>>> instr.write('*IDN?')
7
>>> instr.read()
'SCPI,MOCK,VERSION_1.0\n' # OK, that's what I expect
>>> instr.write('*IDN?') # we don't fetch that response from the instrument
7
>>> id(instr)
140011221241280
>>> del instr # Kill the instrument (or instr.close())
>>> del rm # (or rm.close())
>>> rm = pyvisa.ResourceManager(visa_library='@sim')
>>> instr = rm.open_resource('ASRL2::INSTR')
>>> instr.read() # Why is this response in this different instrument object?
'SCPI,MOCK,VERSION_1.0\n'
>>> id(instr)
140011221241472 # the IDs of the instr objects are different, so it's not somehow the same
To fix/avoid this, one needs to call rm.close(). instr.close() is neither sufficient nor necessary.
Matthieu said:
The fact that closing the instrument does not solve the issue still says that something is off. Instruments do not share outgoing buffers between connections and we should mimic that.
I observe weird problems running pytest tests with pyvisa-sim backed fixture objects, in that replies remain in a read buffer despite the objects + resource managers being destroyed:
To fix/avoid this, one needs to call
rm.close().instr.close()is neither sufficient nor necessary.Matthieu said:
Originally posted by @bilderbuchi in https://github.com/pyvisa/pyvisa-sim/issues/68#issuecomment-1404155350