Merge pull request #4631 from takluyver/i4629

Use argument lists for command help tests

IPython/testing/tools.py

@@ -425,7 +425,7 b' def monkeypatch(obj, name, attr):'
 
 def help_output_test(subcommand=''):
     """test that `ipython [subcommand] -h` works"""
-    cmd = ' '.join(get_ipython_cmd() + [subcommand, '-h'])
+    cmd = get_ipython_cmd() + [subcommand, '-h']
     out, err, rc = get_output_error_code(cmd)
     nt.assert_equal(rc, 0, err)
     nt.assert_not_in("Traceback", err)
@@ -436,7 +436,7 b" def help_output_test(subcommand=''):"
 
 def help_all_output_test(subcommand=''):
     """test that `ipython [subcommand] --help-all` works"""
-    cmd = ' '.join(get_ipython_cmd() + [subcommand, '--help-all'])
+    cmd = get_ipython_cmd() + [subcommand, '--help-all']
     out, err, rc = get_output_error_code(cmd)
     nt.assert_equal(rc, 0, err)
     nt.assert_not_in("Traceback", err)

IPython/utils/_process_common.py

@@ -47,9 +47,10 b' def process_handler(cmd, callback, stderr=subprocess.PIPE):'
 
     Parameters
     ----------
-    cmd : str
-      A string to be executed with the underlying system shell (by calling
-    :func:`Popen` with ``shell=True``.
+    cmd : str or list
+      A command to be executed by the system, using :class:`subprocess.Popen`.
+      If a string is passed, it will be run in the system shell. If a list is
+      passed, it will be used directly as arguments.
 
     callback : callable
       A one-argument function that will be called with the Popen object.
@@ -68,7 +69,7 b' def process_handler(cmd, callback, stderr=subprocess.PIPE):'
     sys.stderr.flush()
     # On win32, close_fds can't be true when using pipes for stdin/out/err
     close_fds = sys.platform != 'win32'
-    p = subprocess.Popen(cmd, shell=True,
+    p = subprocess.Popen(cmd, shell=isinstance(cmd, py3compat.string_types),
                          stdin=subprocess.PIPE,
                          stdout=subprocess.PIPE,
                          stderr=stderr,
@@ -107,7 +108,7 b' def getoutput(cmd):'
 
     Parameters
     ----------
-    cmd : str
+    cmd : str or list
       A command to be executed in the system shell.
 
     Returns
@@ -131,7 +132,7 b' def getoutputerror(cmd):'
 
     Parameters
     ----------
-    cmd : str
+    cmd : str or list
       A command to be executed in the system shell.
 
     Returns
@@ -149,7 +150,7 b' def get_output_error_code(cmd):'
 
     Parameters
     ----------
-    cmd : str
+    cmd : str or list
       A command to be executed in the system shell.
 
     Returns

IPython/utils/_process_win32.py

@@ -112,7 +112,7 b' def system(cmd):'
 
     Parameters
     ----------
-    cmd : str
+    cmd : str or list
       A command to be executed in the system shell.
 
     Returns
@@ -138,7 +138,7 b' def getoutput(cmd):'
 
     Parameters
     ----------
-    cmd : str
+    cmd : str or list
       A command to be executed in the system shell.
 
     Returns