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