/
utils.py
161 lines (134 loc) · 4.75 KB
/
utils.py
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"""utilities for testing IPython kernels"""
# Copyright (c) IPython Development Team.
# Distributed under the terms of the Modified BSD License.
import atexit
from contextlib import contextmanager
from subprocess import PIPE, STDOUT
try:
from queue import Empty # Py 3
except ImportError:
from Queue import Empty # Py 2
import nose
import nose.tools as nt
from IPython.kernel import manager
#-------------------------------------------------------------------------------
# Globals
#-------------------------------------------------------------------------------
STARTUP_TIMEOUT = 60
TIMEOUT = 15
KM = None
KC = None
#-------------------------------------------------------------------------------
# code
#-------------------------------------------------------------------------------
def start_new_kernel(**kwargs):
"""start a new kernel, and return its Manager and Client
Integrates with our output capturing for tests.
"""
kwargs.update(dict(stdout=nose.iptest_stdstreams_fileno(), stderr=STDOUT))
return manager.start_new_kernel(startup_timeout=STARTUP_TIMEOUT, **kwargs)
def flush_channels(kc=None):
"""flush any messages waiting on the queue"""
from .test_message_spec import validate_message
if kc is None:
kc = KC
for channel in (kc.shell_channel, kc.iopub_channel):
while True:
try:
msg = channel.get_msg(block=True, timeout=0.1)
except Empty:
break
else:
validate_message(msg)
def execute(code='', kc=None, **kwargs):
"""wrapper for doing common steps for validating an execution request"""
from .test_message_spec import validate_message
if kc is None:
kc = KC
msg_id = kc.execute(code=code, **kwargs)
reply = kc.get_shell_msg(timeout=TIMEOUT)
validate_message(reply, 'execute_reply', msg_id)
busy = kc.get_iopub_msg(timeout=TIMEOUT)
validate_message(busy, 'status', msg_id)
nt.assert_equal(busy['content']['execution_state'], 'busy')
if not kwargs.get('silent'):
execute_input = kc.get_iopub_msg(timeout=TIMEOUT)
validate_message(execute_input, 'execute_input', msg_id)
nt.assert_equal(execute_input['content']['code'], code)
return msg_id, reply['content']
def start_global_kernel():
"""start the global kernel (if it isn't running) and return its client"""
global KM, KC
if KM is None:
KM, KC = start_new_kernel()
atexit.register(stop_global_kernel)
else:
flush_channels(KC)
return KC
@contextmanager
def kernel():
"""Context manager for the global kernel instance
Should be used for most kernel tests
Returns
-------
kernel_client: connected KernelClient instance
"""
yield start_global_kernel()
def uses_kernel(test_f):
"""Decorator for tests that use the global kernel"""
def wrapped_test():
with kernel() as kc:
test_f(kc)
wrapped_test.__doc__ = test_f.__doc__
wrapped_test.__name__ = test_f.__name__
return wrapped_test
def stop_global_kernel():
"""Stop the global shared kernel instance, if it exists"""
global KM, KC
KC.stop_channels()
KC = None
if KM is None:
return
KM.shutdown_kernel(now=True)
KM = None
def new_kernel(argv=None):
"""Context manager for a new kernel in a subprocess
Should only be used for tests where the kernel must not be re-used.
Returns
-------
kernel_client: connected KernelClient instance
"""
kwargs = dict(stdout=nose.iptest_stdstreams_fileno(), stderr=STDOUT,
startup_timeout=STARTUP_TIMEOUT)
if argv is not None:
kwargs['extra_arguments'] = argv
return manager.run_kernel(**kwargs)
def assemble_output(iopub):
"""assemble stdout/err from an execution"""
stdout = ''
stderr = ''
while True:
msg = iopub.get_msg(block=True, timeout=1)
msg_type = msg['msg_type']
content = msg['content']
if msg_type == 'status' and content['execution_state'] == 'idle':
# idle message signals end of output
break
elif msg['msg_type'] == 'stream':
if content['name'] == 'stdout':
stdout += content['text']
elif content['name'] == 'stderr':
stderr += content['text']
else:
raise KeyError("bad stream: %r" % content['name'])
else:
# other output, ignored
pass
return stdout, stderr
def wait_for_idle(kc):
while True:
msg = kc.iopub_channel.get_msg(block=True, timeout=1)
msg_type = msg['msg_type']
content = msg['content']
if msg_type == 'status' and content['execution_state'] == 'idle':
break