test re-entrant embed_kernel

IPython/zmq/tests/test_embed_kernel.py

@@ -1,158 +1,188 b''
 """test IPython.embed_kernel()"""
 
 #-------------------------------------------------------------------------------
 #  Copyright (C) 2012  The IPython Development Team
 #
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING, distributed as part of this software.
 #-------------------------------------------------------------------------------
 
 #-------------------------------------------------------------------------------
 # Imports
 #-------------------------------------------------------------------------------
 
 import os
 import shutil
 import sys
 import tempfile
 import time
 
 from contextlib import contextmanager
 from subprocess import Popen, PIPE
 
 import nose.tools as nt
 
 from IPython.zmq.blockingkernelmanager import BlockingKernelManager
 from IPython.utils import path
 
 
 #-------------------------------------------------------------------------------
 # Tests
 #-------------------------------------------------------------------------------
 
 def setup():
     """setup temporary IPYTHONDIR for tests"""
     global IPYTHONDIR
     global env
     global save_get_ipython_dir
     
     IPYTHONDIR = tempfile.mkdtemp()
     env = dict(IPYTHONDIR=IPYTHONDIR)
     save_get_ipython_dir = path.get_ipython_dir
     path.get_ipython_dir = lambda : IPYTHONDIR
 
 
 def teardown():
     path.get_ipython_dir = save_get_ipython_dir
     
     try:
         shutil.rmtree(IPYTHONDIR)
     except (OSError, IOError):
         # no such file
         pass
 
 
 @contextmanager
 def setup_kernel(cmd):
     """start an embedded kernel in a subprocess, and wait for it to be ready
     
     Returns
     -------
     kernel_manager: connected KernelManager instance
     """
     kernel = Popen([sys.executable, '-c', cmd], stdout=PIPE, stderr=PIPE, env=env)
     connection_file = os.path.join(IPYTHONDIR,
                                     'profile_default',
                                     'security',
                                     'kernel-%i.json' % kernel.pid
     )
     # wait for connection file to exist, timeout after 5s
     tic = time.time()
     while not os.path.exists(connection_file) and kernel.poll() is None and time.time() < tic + 5:
         time.sleep(0.1)
     
     if not os.path.exists(connection_file):
         if kernel.poll() is None:
             kernel.terminate()
         raise IOError("Connection file %r never arrived" % connection_file)
     
     if kernel.poll() is not None:
         raise IOError("Kernel failed to start")
     
     km = BlockingKernelManager(connection_file=connection_file)
     km.load_connection_file()
     km.start_channels()
     
     try:
         yield km
     finally:
         km.stop_channels()
 
 def test_embed_kernel_basic():
     """IPython.embed_kernel() is basically functional"""
     cmd = '\n'.join([
         'from IPython import embed_kernel',
         'def go():',
         '    a=5',
         '    b="hi there"',
         '    embed_kernel()',
         'go()',
         '',
     ])
     
     with setup_kernel(cmd) as km:
         shell = km.shell_channel
     
         # oinfo a (int)
         msg_id = shell.object_info('a')
         msg = shell.get_msg(block=True, timeout=2)
         content = msg['content']
         nt.assert_true(content['found'])
     
         msg_id = shell.execute("c=a*2")
         msg = shell.get_msg(block=True, timeout=2)
         content = msg['content']
         nt.assert_equals(content['status'], u'ok')
 
         # oinfo c (should be 10)
         msg_id = shell.object_info('c')
         msg = shell.get_msg(block=True, timeout=2)
         content = msg['content']
         nt.assert_true(content['found'])
         nt.assert_equals(content['string_form'], u'10')
 
 def test_embed_kernel_namespace():
     """IPython.embed_kernel() inherits calling namespace"""
     cmd = '\n'.join([
         'from IPython import embed_kernel',
         'def go():',
         '    a=5',
         '    b="hi there"',
         '    embed_kernel()',
         'go()',
         '',
     ])
     
     with setup_kernel(cmd) as km:
         shell = km.shell_channel
     
         # oinfo a (int)
         msg_id = shell.object_info('a')
         msg = shell.get_msg(block=True, timeout=2)
         content = msg['content']
         nt.assert_true(content['found'])
         nt.assert_equals(content['string_form'], u'5')
 
         # oinfo b (str)
         msg_id = shell.object_info('b')
         msg = shell.get_msg(block=True, timeout=2)
         content = msg['content']
         nt.assert_true(content['found'])
         nt.assert_equals(content['string_form'], u'hi there')
 
         # oinfo c (undefined)
         msg_id = shell.object_info('c')
         msg = shell.get_msg(block=True, timeout=2)
         content = msg['content']
         nt.assert_false(content['found'])
 
+def test_embed_kernel_reentrant():
+    """IPython.embed_kernel() can be called multiple times"""
+    cmd = '\n'.join([
+        'from IPython import embed_kernel',
+        'count = 0',
+        'def go():',
+        '    global count',
+        '    embed_kernel()',
+        '    count = count + 1',
+        '',
+        'while True:'
+        '    go()',
+        '',
+    ])
+    
+    with setup_kernel(cmd) as km:
+        shell = km.shell_channel
+        for i in range(5):
+            msg_id = shell.object_info('count')
+            msg = shell.get_msg(block=True, timeout=2)
+            content = msg['content']
+            nt.assert_true(content['found'])
+            nt.assert_equals(content['string_form'], unicode(i))
+            
+            # exit from embed_kernel
+            shell.execute("get_ipython().exit_now = True")
+            msg = shell.get_msg(block=True, timeout=2)
+            time.sleep(0.2)
+
+