diff --git a/src/allmydata/scripts/create_node.py b/src/allmydata/scripts/create_node.py
index 159e7a8a4..891c03a82 100644
--- a/src/allmydata/scripts/create_node.py
+++ b/src/allmydata/scripts/create_node.py
@@ -1,6 +1,4 @@
-
-import os, sys
-
+import os
 from allmydata.scripts.common import BasedirOptions, NoDefaultBasedirOptions
 from allmydata.scripts.default_nodedir import _default_nodedir
 from allmydata.util.assertutil import precondition
@@ -129,7 +127,9 @@ def write_client_config(c, config):
     c.write("enabled = false\n")
     c.write("\n")
 
-def create_node(config, out=sys.stdout, err=sys.stderr):
+def create_node(config):
+    out = config.stdout
+    err = config.stderr
     basedir = config['basedir']
     # This should always be called with an absolute Unicode basedir.
     precondition(isinstance(basedir, unicode), basedir)
@@ -162,12 +162,14 @@ def create_node(config, out=sys.stdout, err=sys.stderr):
         print >>out, " Please set [node]nickname= in tahoe.cfg"
     return 0
 
-def create_client(config, out=sys.stdout, err=sys.stderr):
+def create_client(config):
     config['no-storage'] = True
-    return create_node(config, out=out, err=err)
+    return create_node(config)
 
 
-def create_introducer(config, out=sys.stdout, err=sys.stderr):
+def create_introducer(config):
+    out = config.stdout
+    err = config.stderr
     basedir = config['basedir']
     # This should always be called with an absolute Unicode basedir.
     precondition(isinstance(basedir, unicode), basedir)
diff --git a/src/allmydata/scripts/runner.py b/src/allmydata/scripts/runner.py
index 361cdfa46..131aa35d6 100644
--- a/src/allmydata/scripts/runner.py
+++ b/src/allmydata/scripts/runner.py
@@ -3,6 +3,7 @@ import os, sys
 from cStringIO import StringIO
 
 from twisted.python import usage
+from twisted.internet import defer, task, threads
 
 from allmydata.scripts.common import get_default_nodedir
 from allmydata.scripts import debug, create_node, startstop_node, cli, \
@@ -89,32 +90,17 @@ create_dispatch = {}
 for module in (create_node, stats_gatherer):
     create_dispatch.update(module.dispatch)
 
-def runner(argv,
-           run_by_human=True,
-           stdin=None, stdout=None, stderr=None,
-           install_node_control=True, additional_commands=None):
-
-    assert sys.version_info < (3,), ur"Tahoe-LAFS does not run under Python 3. Please use Python 2.7.x."
-
-    stdin  = stdin  or sys.stdin
-    stdout = stdout or sys.stdout
-    stderr = stderr or sys.stderr
+def parse_options(argv, config=None):
+    if not config:
+        config = Options()
+    config.parseOptions(argv) # may raise usage.error
+    return config
 
+def parse_or_exit_with_explanation(argv, stdout=sys.stdout):
     config = Options()
-    if install_node_control:
-        config.subCommands.extend(startstop_node.subCommands)
-
-    ac_dispatch = {}
-    if additional_commands:
-        for ac in additional_commands:
-            config.subCommands.extend(ac.subCommands)
-            ac_dispatch.update(ac.dispatch)
-
     try:
-        config.parseOptions(argv)
+        parse_options(argv, config=config)
     except usage.error, e:
-        if not run_by_human:
-            raise
         c = config
         while hasattr(c, 'subOptions'):
             c = c.subOptions
@@ -124,51 +110,68 @@ def runner(argv,
         except Exception:
             msg = repr(e)
         print >>stdout, "%s:  %s\n" % (sys.argv[0], quote_output(msg, quotemarks=False))
-        return 1
+        sys.exit(1)
+    return config
 
+def dispatch(config,
+             stdin=sys.stdin, stdout=sys.stdout, stderr=sys.stderr):
     command = config.subCommand
     so = config.subOptions
-
     if config['quiet']:
         stdout = StringIO()
-
     so.stdout = stdout
     so.stderr = stderr
     so.stdin = stdin
 
     if command in create_dispatch:
-        rc = create_dispatch[command](so, stdout, stderr)
+        f = create_dispatch[command]
     elif command in startstop_node.dispatch:
-        rc = startstop_node.dispatch[command](so, stdout, stderr)
+        f = startstop_node.dispatch[command]
     elif command in debug.dispatch:
-        rc = debug.dispatch[command](so)
+        f = debug.dispatch[command]
     elif command in admin.dispatch:
-        rc = admin.dispatch[command](so)
+        f = admin.dispatch[command]
     elif command in cli.dispatch:
-        rc = cli.dispatch[command](so)
+        # these are blocking, and must be run in a thread
+        f0 = cli.dispatch[command]
+        f = lambda so: threads.deferToThread(f0, so)
     elif command in magic_folder_cli.dispatch:
-        rc = magic_folder_cli.dispatch[command](so)
-    elif command in ac_dispatch:
-        rc = ac_dispatch[command](so, stdout, stderr)
+        # same
+        f0 = magic_folder_cli.dispatch[command]
+        f = lambda so: threads.deferToThread(f0, so)
     else:
         raise usage.UsageError()
 
-    return rc
+    d = defer.maybeDeferred(f, so)
+    # the calling convention for CLI dispatch functions is that they either:
+    # 1: succeed and return rc=0
+    # 2: print explanation to stderr and return rc!=0
+    # 3: raise an exception that should just be printed normally
+    # 4: return a Deferred that does 1 or 2 or 3
+    def _raise_sys_exit(rc):
+        sys.exit(rc)
+    d.addCallback(_raise_sys_exit)
+    return d
 
+def run():
+    assert sys.version_info < (3,), ur"Tahoe-LAFS does not run under Python 3. Please use Python 2.7.x."
 
-def run(install_node_control=True):
-    try:
-        if sys.platform == "win32":
-            from allmydata.windows.fixups import initialize
-            initialize()
-
-        rc = runner(sys.argv[1:], install_node_control=install_node_control)
-    except Exception:
-        import traceback
-        traceback.print_exc()
-        rc = 1
-
-    sys.exit(rc)
+    if sys.platform == "win32":
+        from allmydata.windows.fixups import initialize
+        initialize()
+    d = defer.maybeDeferred(parse_or_exit_with_explanation, sys.argv[1:])
+    d.addCallback(dispatch)
+    def _show_exception(f):
+        # when task.react() notices a non-SystemExit exception, it does
+        # log.err() with the failure and then exits with rc=1. We want this
+        # to actually print the exception to stderr, like it would do if we
+        # weren't using react().
+        if f.check(SystemExit):
+            return f # dispatch function handled it
+        f.printTraceback(file=sys.stderr)
+        sys.exit(1)
+    d.addErrback(_show_exception)
+    task.react(lambda _reactor: d) # doesn't return: calls sys.exit(rc)
 
 if __name__ == "__main__":
     run()
diff --git a/src/allmydata/scripts/startstop_node.py b/src/allmydata/scripts/startstop_node.py
index 761984e0f..a7a629f4c 100644
--- a/src/allmydata/scripts/startstop_node.py
+++ b/src/allmydata/scripts/startstop_node.py
@@ -99,7 +99,9 @@ def identify_node_type(basedir):
             return t
     return None
 
-def start(config, out=sys.stdout, err=sys.stderr):
+def start(config):
+    out = config.stdout
+    err = config.stderr
     basedir = config['basedir']
     quoted_basedir = quote_local_unicode_path(basedir)
     print >>out, "STARTING", quoted_basedir
@@ -169,7 +171,9 @@ def start(config, out=sys.stdout, err=sys.stderr):
     # we should only reach here if --nodaemon or equivalent was used
     return 0
 
-def stop(config, out=sys.stdout, err=sys.stderr):
+def stop(config):
+    out = config.stdout
+    err = config.stderr
     basedir = config['basedir']
     quoted_basedir = quote_local_unicode_path(basedir)
     print >>out, "STOPPING", quoted_basedir
@@ -227,23 +231,24 @@ def stop(config, out=sys.stdout, err=sys.stderr):
     # we define rc=1 to mean "I think something is still running, sorry"
     return 1
 
-def restart(config, stdout, stderr):
-    rc = stop(config, stdout, stderr)
+def restart(config):
+    stderr = config.stderr
+    rc = stop(config)
     if rc == 2:
         print >>stderr, "ignoring couldn't-stop"
         rc = 0
     if rc:
         print >>stderr, "not restarting"
         return rc
-    return start(config, stdout, stderr)
+    return start(config)
 
-def run(config, stdout, stderr):
+def run(config):
     config.twistd_args = config.twistd_args + ("--nodaemon",)
     # Previously we would do the equivalent of adding ("--logfile",
     # "tahoesvc.log"), but that redirects stdout/stderr which is often
     # unhelpful, and the user can add that option explicitly if they want.
 
-    return start(config, stdout, stderr)
+    return start(config)
 
 
 subCommands = [
diff --git a/src/allmydata/scripts/stats_gatherer.py b/src/allmydata/scripts/stats_gatherer.py
index 71a5ece14..cb5d1400c 100644
--- a/src/allmydata/scripts/stats_gatherer.py
+++ b/src/allmydata/scripts/stats_gatherer.py
@@ -1,4 +1,4 @@
-import os, sys
+import os
 from twisted.python import usage
 from allmydata.scripts.common import NoDefaultBasedirOptions
 from allmydata.scripts.create_node import write_tac
@@ -56,7 +56,8 @@ class CreateStatsGathererOptions(NoDefaultBasedirOptions):
     """
 
 
-def create_stats_gatherer(config, out=sys.stdout, err=sys.stderr):
+def create_stats_gatherer(config):
+    err = config.stderr
     basedir = config['basedir']
     # This should always be called with an absolute Unicode basedir.
     precondition(isinstance(basedir, unicode), basedir)
diff --git a/src/allmydata/test/cli/common.py b/src/allmydata/test/cli/common.py
new file mode 100644
index 000000000..852dce52c
--- /dev/null
+++ b/src/allmydata/test/cli/common.py
@@ -0,0 +1,19 @@
+from ...util.encodingutil import unicode_to_argv
+from ...scripts import runner
+from ..common_util import ReallyEqualMixin, run_cli
+
+def parse_options(basedir, command, args):
+    o = runner.Options()
+    o.parseOptions(["--node-directory", basedir, command] + args)
+    while hasattr(o, "subOptions"):
+        o = o.subOptions
+    return o
+
+class CLITestMixin(ReallyEqualMixin):
+    def do_cli(self, verb, *args, **kwargs):
+        # client_num is used to execute client CLI commands on a specific
+        # client.
+        client_num = kwargs.get("client_num", 0)
+        client_dir = unicode_to_argv(self.get_clientdir(i=client_num))
+        nodeargs = [ "--node-directory", client_dir ]
+        return run_cli(verb, nodeargs=nodeargs, *args, **kwargs)
diff --git a/src/allmydata/test/cli/test_backup.py b/src/allmydata/test/cli/test_backup.py
index 5d39e2825..bc154f1be 100644
--- a/src/allmydata/test/cli/test_backup.py
+++ b/src/allmydata/test/cli/test_backup.py
@@ -14,7 +14,7 @@ from allmydata.util.namespace import Namespace
 from allmydata.scripts import cli, backupdb
 from ..common_util import StallMixin
 from ..no_network import GridTestMixin
-from .test_cli import CLITestMixin, parse_options
+from .common import CLITestMixin, parse_options
 
 timeout = 480 # deep_check takes 360s on Zandr's linksys box, others take > 240s
 
diff --git a/src/allmydata/test/cli/test_check.py b/src/allmydata/test/cli/test_check.py
index 0eaf69099..6b1de52d3 100644
--- a/src/allmydata/test/cli/test_check.py
+++ b/src/allmydata/test/cli/test_check.py
@@ -10,7 +10,7 @@ from allmydata.mutable.publish import MutableData
 from allmydata.immutable import upload
 from allmydata.scripts import debug
 from ..no_network import GridTestMixin
-from .test_cli import CLITestMixin
+from .common import CLITestMixin
 
 timeout = 480 # deep_check takes 360s on Zandr's linksys box, others take > 240s
 
diff --git a/src/allmydata/test/cli/test_cli.py b/src/allmydata/test/cli/test_cli.py
index 43b24264e..c21856036 100644
--- a/src/allmydata/test/cli/test_cli.py
+++ b/src/allmydata/test/cli/test_cli.py
@@ -5,6 +5,7 @@ import urllib, sys
 
 from twisted.trial import unittest
 from twisted.python.monkey import MonkeyPatcher
+from twisted.internet import task
 
 import allmydata
 from allmydata.util import fileutil, hashutil, base32, keyutil
@@ -29,57 +30,16 @@ from allmydata.scripts.common import DEFAULT_ALIAS, get_aliases, get_alias, \
      DefaultAliasMarker
 
 from allmydata.scripts import cli, debug, runner
-from ..common_util import ReallyEqualMixin
+from ..common_util import (ReallyEqualMixin, skip_if_cannot_represent_filename,
+                           run_cli)
 from ..no_network import GridTestMixin
-from twisted.internet import threads # CLI tests use deferToThread
+from .common import CLITestMixin, parse_options
 from twisted.python import usage
 
-from allmydata.util.assertutil import precondition
-from allmydata.util.encodingutil import listdir_unicode, unicode_platform, \
-    get_io_encoding, get_filesystem_encoding, unicode_to_argv
+from allmydata.util.encodingutil import listdir_unicode, get_io_encoding
 
 timeout = 480 # deep_check takes 360s on Zandr's linksys box, others take > 240s
 
-def parse_options(basedir, command, args):
-    o = runner.Options()
-    o.parseOptions(["--node-directory", basedir, command] + args)
-    while hasattr(o, "subOptions"):
-        o = o.subOptions
-    return o
-
-class CLITestMixin(ReallyEqualMixin):
-    def do_cli(self, verb, *args, **kwargs):
-        precondition(not [True for arg in args if not isinstance(arg, str)],
-                     "arguments to do_cli must be strs -- convert using unicode_to_argv", args=args)
-
-        # client_num is used to execute client CLI commands on a specific client.
-        client_num = kwargs.get("client_num", 0)
-
-        nodeargs = [
-            "--node-directory", unicode_to_argv(self.get_clientdir(i=client_num)),
-            ]
-        argv = nodeargs + [verb] + list(args)
-        stdin = kwargs.get("stdin", "")
-        stdout, stderr = StringIO(), StringIO()
-        d = threads.deferToThread(runner.runner, argv, run_by_human=False,
-                                  stdin=StringIO(stdin),
-                                  stdout=stdout, stderr=stderr)
-        def _done(rc):
-            return rc, stdout.getvalue(), stderr.getvalue()
-        d.addCallback(_done)
-        return d
-
-    def skip_if_cannot_represent_filename(self, u):
-        precondition(isinstance(u, unicode))
-
-        enc = get_filesystem_encoding()
-        if not unicode_platform():
-            try:
-                u.encode(enc)
-            except UnicodeEncodeError:
-                raise unittest.SkipTest("A non-ASCII filename could not be encoded on this platform.")
-
-
 class CLI(CLITestMixin, unittest.TestCase):
     def _dump_cap(self, *args):
         config = debug.DumpCapOptions()
@@ -534,7 +494,7 @@ class CLI(CLITestMixin, unittest.TestCase):
         filenames = [u'L\u00F4zane', u'Bern', u'Gen\u00E8ve']  # must be NFC
 
         for name in filenames:
-            self.skip_if_cannot_represent_filename(name)
+            skip_if_cannot_represent_filename(name)
 
         basedir = "cli/common/listdir_unicode_good"
         fileutil.make_dirs(basedir)
@@ -552,10 +512,9 @@ class CLI(CLITestMixin, unittest.TestCase):
         exc = Exception("canary")
         ns = Namespace()
 
-        ns.runner_called = False
-        def call_runner(args, install_node_control=True):
-            ns.runner_called = True
-            self.failUnlessEqual(install_node_control, True)
+        ns.parse_called = False
+        def call_parse_or_exit(args):
+            ns.parse_called = True
             raise exc
 
         ns.sys_exit_called = False
@@ -563,13 +522,23 @@ class CLI(CLITestMixin, unittest.TestCase):
             ns.sys_exit_called = True
             self.failUnlessEqual(exitcode, 1)
 
-        patcher = MonkeyPatcher((runner, 'runner', call_runner),
+        def fake_react(f):
+            d = f("reactor")
+            # normally this Deferred would be errbacked with SystemExit, but
+            # since we mocked out sys.exit, it will be fired with None. So
+            # it's safe to drop it on the floor.
+            del d
+
+        patcher = MonkeyPatcher((runner, 'parse_or_exit_with_explanation',
+                                 call_parse_or_exit),
                                 (sys, 'argv', ["tahoe"]),
                                 (sys, 'exit', call_sys_exit),
-                                (sys, 'stderr', stderr))
+                                (sys, 'stderr', stderr),
+                                (task, 'react', fake_react),
+                                )
         patcher.runWithPatches(runner.run)
 
-        self.failUnless(ns.runner_called)
+        self.failUnless(ns.parse_called)
         self.failUnless(ns.sys_exit_called)
         self.failUnlessIn(str(exc), stderr.getvalue())
 
@@ -747,21 +716,9 @@ class Ln(GridTestMixin, CLITestMixin, unittest.TestCase):
 
 
 class Admin(unittest.TestCase):
-    def do_cli(self, *args, **kwargs):
-        argv = list(args)
-        stdin = kwargs.get("stdin", "")
-        stdout, stderr = StringIO(), StringIO()
-        d = threads.deferToThread(runner.runner, argv, run_by_human=False,
-                                  stdin=StringIO(stdin),
-                                  stdout=stdout, stderr=stderr)
-        def _done(res):
-            return stdout.getvalue(), stderr.getvalue()
-        d.addCallback(_done)
-        return d
-
     def test_generate_keypair(self):
-        d = self.do_cli("admin", "generate-keypair")
-        def _done( (stdout, stderr) ):
+        d = run_cli("admin", "generate-keypair")
+        def _done( (rc, stdout, stderr) ):
             lines = [line.strip() for line in stdout.splitlines()]
             privkey_bits = lines[0].split()
             pubkey_bits = lines[1].split()
@@ -780,8 +737,8 @@ class Admin(unittest.TestCase):
 
     def test_derive_pubkey(self):
         priv1,pub1 = keyutil.make_keypair()
-        d = self.do_cli("admin", "derive-pubkey", priv1)
-        def _done( (stdout, stderr) ):
+        d = run_cli("admin", "derive-pubkey", priv1)
+        def _done( (rc, stdout, stderr) ):
             lines = stdout.split("\n")
             privkey_line = lines[0].strip()
             pubkey_line = lines[1].strip()
diff --git a/src/allmydata/test/cli/test_cp.py b/src/allmydata/test/cli/test_cp.py
index 50b538d2f..20136e978 100644
--- a/src/allmydata/test/cli/test_cp.py
+++ b/src/allmydata/test/cli/test_cp.py
@@ -9,7 +9,8 @@ from allmydata.util.encodingutil import (quote_output, get_io_encoding,
                                          unicode_to_output, to_str)
 from allmydata.util.assertutil import _assert
 from ..no_network import GridTestMixin
-from .test_cli import CLITestMixin
+from .common import CLITestMixin
+from ..common_util import skip_if_cannot_represent_filename
 
 timeout = 480 # deep_check takes 360s on Zandr's linksys box, others take > 240s
 
@@ -30,7 +31,7 @@ class Cp(GridTestMixin, CLITestMixin, unittest.TestCase):
         except UnicodeEncodeError:
             raise unittest.SkipTest("A non-ASCII command argument could not be encoded on this platform.")
 
-        self.skip_if_cannot_represent_filename(fn1)
+        skip_if_cannot_represent_filename(fn1)
 
         self.set_up_grid(oneshare=True)
 
@@ -198,7 +199,7 @@ class Cp(GridTestMixin, CLITestMixin, unittest.TestCase):
         except UnicodeEncodeError:
             raise unittest.SkipTest("A non-ASCII command argument could not be encoded on this platform.")
 
-        self.skip_if_cannot_represent_filename(fn1)
+        skip_if_cannot_represent_filename(fn1)
 
         self.set_up_grid(oneshare=True)
 
diff --git a/src/allmydata/test/cli/test_create.py b/src/allmydata/test/cli/test_create.py
index 9e06fa255..c10271a8b 100644
--- a/src/allmydata/test/cli/test_create.py
+++ b/src/allmydata/test/cli/test_create.py
@@ -1,54 +1,53 @@
 import os
-from StringIO import StringIO
 from twisted.trial import unittest
-from allmydata.scripts import runner
+from twisted.internet import defer
 from allmydata.util import configutil
+from ..common_util import run_cli
 
 class Config(unittest.TestCase):
-    def do_cli(self, *args):
-        argv = list(args)
-        stdout, stderr = StringIO(), StringIO()
-        rc = runner.runner(argv, run_by_human=False,
-                           stdout=stdout, stderr=stderr)
-        return rc, stdout.getvalue(), stderr.getvalue()
-
     def read_config(self, basedir):
         tahoe_cfg = os.path.join(basedir, "tahoe.cfg")
         config = configutil.get_config(tahoe_cfg)
         return config
 
+    @defer.inlineCallbacks
     def test_client(self):
         basedir = self.mktemp()
-        rc, out, err = self.do_cli("create-client", basedir)
+        rc, out, err = yield run_cli("create-client", basedir)
         cfg = self.read_config(basedir)
         self.assertEqual(cfg.getboolean("node", "reveal-IP-address"), True)
 
+    @defer.inlineCallbacks
     def test_client_hide_ip(self):
         basedir = self.mktemp()
-        rc, out, err = self.do_cli("create-client", "--hide-ip", basedir)
+        rc, out, err = yield run_cli("create-client", "--hide-ip", basedir)
         cfg = self.read_config(basedir)
         self.assertEqual(cfg.getboolean("node", "reveal-IP-address"), False)
 
+    @defer.inlineCallbacks
     def test_node(self):
         basedir = self.mktemp()
-        rc, out, err = self.do_cli("create-node", basedir)
+        rc, out, err = yield run_cli("create-node", basedir)
         cfg = self.read_config(basedir)
         self.assertEqual(cfg.getboolean("node", "reveal-IP-address"), True)
 
+    @defer.inlineCallbacks
     def test_node_hide_ip(self):
         basedir = self.mktemp()
-        rc, out, err = self.do_cli("create-node", "--hide-ip", basedir)
+        rc, out, err = yield run_cli("create-node", "--hide-ip", basedir)
         cfg = self.read_config(basedir)
         self.assertEqual(cfg.getboolean("node", "reveal-IP-address"), False)
 
+    @defer.inlineCallbacks
     def test_introducer(self):
         basedir = self.mktemp()
-        rc, out, err = self.do_cli("create-introducer", basedir)
+        rc, out, err = yield run_cli("create-introducer", basedir)
         cfg = self.read_config(basedir)
         self.assertEqual(cfg.getboolean("node", "reveal-IP-address"), True)
 
+    @defer.inlineCallbacks
     def test_introducer_hide_ip(self):
         basedir = self.mktemp()
-        rc, out, err = self.do_cli("create-introducer", "--hide-ip", basedir)
+        rc, out, err = yield run_cli("create-introducer", "--hide-ip", basedir)
         cfg = self.read_config(basedir)
         self.assertEqual(cfg.getboolean("node", "reveal-IP-address"), False)
diff --git a/src/allmydata/test/cli/test_create_alias.py b/src/allmydata/test/cli/test_create_alias.py
index 8d2efe29f..5f4b70a54 100644
--- a/src/allmydata/test/cli/test_create_alias.py
+++ b/src/allmydata/test/cli/test_create_alias.py
@@ -6,7 +6,7 @@ from allmydata.scripts.common import get_aliases
 from allmydata.scripts import cli, runner
 from ..no_network import GridTestMixin
 from allmydata.util.encodingutil import quote_output, get_io_encoding
-from .test_cli import CLITestMixin
+from .common import CLITestMixin
 
 timeout = 480 # deep_check takes 360s on Zandr's linksys box, others take > 240s
 
diff --git a/src/allmydata/test/cli/test_list.py b/src/allmydata/test/cli/test_list.py
index 17b58a817..41ea48b2c 100644
--- a/src/allmydata/test/cli/test_list.py
+++ b/src/allmydata/test/cli/test_list.py
@@ -6,7 +6,7 @@ from allmydata.interfaces import MDMF_VERSION, SDMF_VERSION
 from allmydata.mutable.publish import MutableData
 from ..no_network import GridTestMixin
 from allmydata.util.encodingutil import quote_output, get_io_encoding
-from .test_cli import CLITestMixin
+from .common import CLITestMixin
 
 timeout = 480 # deep_check takes 360s on Zandr's linksys box, others take > 240s
 
diff --git a/src/allmydata/test/cli/test_magic_folder.py b/src/allmydata/test/cli/test_magic_folder.py
index a69b763f4..0c9009769 100644
--- a/src/allmydata/test/cli/test_magic_folder.py
+++ b/src/allmydata/test/cli/test_magic_folder.py
@@ -10,7 +10,7 @@ from allmydata.util.assertutil import precondition
 from allmydata.util import fileutil
 from allmydata.scripts.common import get_aliases
 from ..no_network import GridTestMixin
-from .test_cli import CLITestMixin
+from .common import CLITestMixin
 from allmydata.scripts import magic_folder_cli
 from allmydata.util.fileutil import abspath_expanduser_unicode
 from allmydata.util.encodingutil import unicode_to_argv
diff --git a/src/allmydata/test/cli/test_mv.py b/src/allmydata/test/cli/test_mv.py
index 1c72d79b4..40b1474c3 100644
--- a/src/allmydata/test/cli/test_mv.py
+++ b/src/allmydata/test/cli/test_mv.py
@@ -3,7 +3,7 @@ from twisted.trial import unittest
 from allmydata.util import fileutil
 from ..no_network import GridTestMixin
 from allmydata.scripts import tahoe_mv
-from .test_cli import CLITestMixin
+from .common import CLITestMixin
 
 timeout = 480 # deep_check takes 360s on Zandr's linksys box, others take > 240s
 
diff --git a/src/allmydata/test/cli/test_put.py b/src/allmydata/test/cli/test_put.py
index 1b3189f55..c62bdab85 100644
--- a/src/allmydata/test/cli/test_put.py
+++ b/src/allmydata/test/cli/test_put.py
@@ -6,9 +6,10 @@ from allmydata.util import fileutil
 from allmydata.scripts.common import get_aliases
 from allmydata.scripts import cli
 from ..no_network import GridTestMixin
+from ..common_util import skip_if_cannot_represent_filename
 from allmydata.util.encodingutil import get_io_encoding, unicode_to_argv
 from allmydata.util.fileutil import abspath_expanduser_unicode
-from .test_cli import CLITestMixin
+from .common import CLITestMixin
 
 timeout = 480 # deep_check takes 360s on Zandr's linksys box, others take > 240s
 
@@ -427,7 +428,7 @@ class Put(GridTestMixin, CLITestMixin, unittest.TestCase):
         except UnicodeEncodeError:
             raise unittest.SkipTest("A non-ASCII command argument could not be encoded on this platform.")
 
-        self.skip_if_cannot_represent_filename(u"\u00E0 trier.txt")
+        skip_if_cannot_represent_filename(u"\u00E0 trier.txt")
 
         self.basedir = "cli/Put/immutable_from_file_unicode"
         self.set_up_grid(oneshare=True)
diff --git a/src/allmydata/test/common_util.py b/src/allmydata/test/common_util.py
index 9d6bdf3f4..982b8a3ec 100644
--- a/src/allmydata/test/common_util.py
+++ b/src/allmydata/test/common_util.py
@@ -1,12 +1,50 @@
 import os, signal, sys, time
 from random import randrange
+from cStringIO import StringIO
 
 from twisted.internet import reactor, defer
 from twisted.python import failure
+from twisted.trial import unittest
 
 from allmydata.util import fileutil, log
+from ..util.assertutil import precondition
 from allmydata.util.encodingutil import unicode_platform, get_filesystem_encoding
+from ..scripts import runner
 
+def skip_if_cannot_represent_filename(u):
+    precondition(isinstance(u, unicode))
+
+    enc = get_filesystem_encoding()
+    if not unicode_platform():
+        try:
+            u.encode(enc)
+        except UnicodeEncodeError:
+            raise unittest.SkipTest("A non-ASCII filename could not be encoded on this platform.")
+
+def run_cli(verb, *args, **kwargs):
+    precondition(not [True for arg in args if not isinstance(arg, str)],
+                 "arguments to do_cli must be strs -- convert using unicode_to_argv", args=args)
+    nodeargs = kwargs.get("nodeargs", [])
+    argv = nodeargs + [verb] + list(args)
+    stdin = kwargs.get("stdin", "")
+    stdout, stderr = StringIO(), StringIO()
+    d = defer.succeed(argv)
+    d.addCallback(runner.parse_or_exit_with_explanation, stdout=stdout)
+    d.addCallback(runner.dispatch,
+                  stdin=StringIO(stdin),
+                  stdout=stdout, stderr=stderr)
+    def _done(rc):
+        return 0, stdout.getvalue(), stderr.getvalue()
+    def _err(f):
+        f.trap(SystemExit)
+        return f.value.code, stdout.getvalue(), stderr.getvalue()
+    d.addCallbacks(_done, _err)
+    return d
+
+def parse_cli(*argv):
+    # This parses the CLI options (synchronously), and returns the Options
+    # argument, or throws usage.UsageError if something went wrong.
+    return runner.parse_options(argv)
 
 class DevNullDictionary(dict):
     def __setitem__(self, key, value):
diff --git a/src/allmydata/test/test_backupdb.py b/src/allmydata/test/test_backupdb.py
index 835e25315..979c20016 100644
--- a/src/allmydata/test/test_backupdb.py
+++ b/src/allmydata/test/test_backupdb.py
@@ -4,9 +4,9 @@ from StringIO import StringIO
 from twisted.trial import unittest
 
 from allmydata.util import fileutil
-from allmydata.util.encodingutil import listdir_unicode, get_filesystem_encoding, unicode_platform
-from allmydata.util.assertutil import precondition
+from allmydata.util.encodingutil import listdir_unicode
 from allmydata.scripts import backupdb
+from .common_util import skip_if_cannot_represent_filename
 
 class BackupDB(unittest.TestCase):
     def create(self, dbfile):
@@ -15,16 +15,6 @@ class BackupDB(unittest.TestCase):
         self.failUnless(bdb, "unable to create backupdb from %r" % (dbfile,))
         return bdb
 
-    def skip_if_cannot_represent_filename(self, u):
-        precondition(isinstance(u, unicode))
-
-        enc = get_filesystem_encoding()
-        if not unicode_platform():
-            try:
-                u.encode(enc)
-            except UnicodeEncodeError:
-                raise unittest.SkipTest("A non-ASCII filename could not be encoded on this platform.")
-
     def test_basic(self):
         self.basedir = basedir = os.path.join("backupdb", "create")
         fileutil.make_dirs(basedir)
@@ -222,8 +212,8 @@ class BackupDB(unittest.TestCase):
         self.failIf(r.was_created())
 
     def test_unicode(self):
-        self.skip_if_cannot_represent_filename(u"f\u00f6\u00f6.txt")
-        self.skip_if_cannot_represent_filename(u"b\u00e5r.txt")
+        skip_if_cannot_represent_filename(u"f\u00f6\u00f6.txt")
+        skip_if_cannot_represent_filename(u"b\u00e5r.txt")
 
         self.basedir = basedir = os.path.join("backupdb", "unicode")
         fileutil.make_dirs(basedir)
diff --git a/src/allmydata/test/test_configutil.py b/src/allmydata/test/test_configutil.py
index ef58dfcdf..7fb34cc61 100644
--- a/src/allmydata/test/test_configutil.py
+++ b/src/allmydata/test/test_configutil.py
@@ -4,12 +4,11 @@ from twisted.trial import unittest
 
 from allmydata.util import configutil
 from allmydata.test.no_network import GridTestMixin
-from .cli.test_cli import CLITestMixin
 from ..scripts import create_node
 from .. import client
 
 
-class ConfigUtilTests(CLITestMixin, GridTestMixin, unittest.TestCase):
+class ConfigUtilTests(GridTestMixin, unittest.TestCase):
 
     def test_config_utils(self):
         self.basedir = "cli/ConfigUtilTests/test-config-utils"
diff --git a/src/allmydata/test/test_deepcheck.py b/src/allmydata/test/test_deepcheck.py
index fd9db7ec1..725f43e84 100644
--- a/src/allmydata/test/test_deepcheck.py
+++ b/src/allmydata/test/test_deepcheck.py
@@ -1,15 +1,12 @@
 
 import os, simplejson, urllib
-from cStringIO import StringIO
 from twisted.trial import unittest
 from twisted.internet import defer
-from twisted.internet import threads # CLI tests use deferToThread
 from allmydata.immutable import upload
 from allmydata.mutable.common import UnrecoverableFileError
 from allmydata.mutable.publish import MutableData
 from allmydata.util import idlib
 from allmydata.util import base32
-from allmydata.scripts import runner
 from allmydata.interfaces import ICheckResults, ICheckAndRepairResults, \
      IDeepCheckResults, IDeepCheckAndRepairResults
 from allmydata.monitor import Monitor, OperationCancelledError
@@ -18,19 +15,13 @@ from twisted.web.client import getPage
 
 from allmydata.test.common import ErrorMixin, _corrupt_mutable_share_data, \
      ShouldFailMixin
-from allmydata.test.common_util import StallMixin
+from .common_util import StallMixin, run_cli
 from allmydata.test.no_network import GridTestMixin
+from .cli.common import CLITestMixin
 
 timeout = 2400 # One of these took 1046.091s on Zandr's ARM box.
 
 class MutableChecker(GridTestMixin, unittest.TestCase, ErrorMixin):
-    def _run_cli(self, argv):
-        stdout, stderr = StringIO(), StringIO()
-        # this can only do synchronous operations
-        assert argv[0] == "debug"
-        runner.runner(argv, run_by_human=False, stdout=stdout, stderr=stderr)
-        return stdout.getvalue()
-
     def test_good(self):
         self.basedir = "deepcheck/MutableChecker/good"
         self.set_up_grid()
@@ -130,7 +121,8 @@ class MutableChecker(GridTestMixin, unittest.TestCase, ErrorMixin):
         return d
 
 
-class DeepCheckBase(GridTestMixin, ErrorMixin, StallMixin, ShouldFailMixin):
+class DeepCheckBase(GridTestMixin, ErrorMixin, StallMixin, ShouldFailMixin,
+                    CLITestMixin):
 
     def web_json(self, n, **kwargs):
         kwargs["output"] = "json"
@@ -727,17 +719,6 @@ class DeepCheckWebGood(DeepCheckBase, unittest.TestCase):
 
         return d
 
-    def _run_cli(self, argv, stdin=""):
-        #print "CLI:", argv
-        stdout, stderr = StringIO(), StringIO()
-        d = threads.deferToThread(runner.runner, argv, run_by_human=False,
-                                  stdin=StringIO(stdin),
-                                  stdout=stdout, stderr=stderr)
-        def _done(res):
-            return stdout.getvalue(), stderr.getvalue()
-        d.addCallback(_done)
-        return d
-
     def do_test_cli_good(self, ignored):
         d = defer.succeed(None)
         d.addCallback(lambda ign: self.do_cli_manifest_stream1())
@@ -757,11 +738,8 @@ class DeepCheckWebGood(DeepCheckBase, unittest.TestCase):
         self.failUnless(base32.b2a(self.large.get_storage_index()) in lines)
 
     def do_cli_manifest_stream1(self):
-        basedir = self.get_clientdir(0)
-        d = self._run_cli(["--node-directory", basedir,
-                           "manifest",
-                           self.root_uri])
-        def _check((out,err)):
+        d = self.do_cli("manifest", self.root_uri)
+        def _check((rc,out,err)):
             self.failUnlessEqual(err, "")
             lines = [l for l in out.split("\n") if l]
             self.failUnlessEqual(len(lines), 8)
@@ -785,12 +763,8 @@ class DeepCheckWebGood(DeepCheckBase, unittest.TestCase):
         return d
 
     def do_cli_manifest_stream2(self):
-        basedir = self.get_clientdir(0)
-        d = self._run_cli(["--node-directory", basedir,
-                           "manifest",
-                           "--raw",
-                           self.root_uri])
-        def _check((out,err)):
+        d = self.do_cli("manifest", "--raw", self.root_uri)
+        def _check((rc,out,err)):
             self.failUnlessEqual(err, "")
             # this should be the same as the POST t=stream-manifest output
             self._check_streamed_manifest(out)
@@ -798,24 +772,16 @@ class DeepCheckWebGood(DeepCheckBase, unittest.TestCase):
         return d
 
     def do_cli_manifest_stream3(self):
-        basedir = self.get_clientdir(0)
-        d = self._run_cli(["--node-directory", basedir,
-                           "manifest",
-                           "--storage-index",
-                           self.root_uri])
-        def _check((out,err)):
+        d = self.do_cli("manifest", "--storage-index", self.root_uri)
+        def _check((rc,out,err)):
             self.failUnlessEqual(err, "")
             self._check_manifest_storage_index(out)
         d.addCallback(_check)
         return d
 
     def do_cli_manifest_stream4(self):
-        basedir = self.get_clientdir(0)
-        d = self._run_cli(["--node-directory", basedir,
-                           "manifest",
-                           "--verify-cap",
-                           self.root_uri])
-        def _check((out,err)):
+        d = self.do_cli("manifest", "--verify-cap", self.root_uri)
+        def _check((rc,out,err)):
             self.failUnlessEqual(err, "")
             lines = [l for l in out.split("\n") if l]
             self.failUnlessEqual(len(lines), 3)
@@ -826,12 +792,8 @@ class DeepCheckWebGood(DeepCheckBase, unittest.TestCase):
         return d
 
     def do_cli_manifest_stream5(self):
-        basedir = self.get_clientdir(0)
-        d = self._run_cli(["--node-directory", basedir,
-                           "manifest",
-                           "--repair-cap",
-                           self.root_uri])
-        def _check((out,err)):
+        d = self.do_cli("manifest", "--repair-cap", self.root_uri)
+        def _check((rc,out,err)):
             self.failUnlessEqual(err, "")
             lines = [l for l in out.split("\n") if l]
             self.failUnlessEqual(len(lines), 3)
@@ -842,11 +804,8 @@ class DeepCheckWebGood(DeepCheckBase, unittest.TestCase):
         return d
 
     def do_cli_stats1(self):
-        basedir = self.get_clientdir(0)
-        d = self._run_cli(["--node-directory", basedir,
-                           "stats",
-                           self.root_uri])
-        def _check3((out,err)):
+        d = self.do_cli("stats", self.root_uri)
+        def _check3((rc,out,err)):
             lines = [l.strip() for l in out.split("\n") if l]
             self.failUnless("count-immutable-files: 1" in lines)
             self.failUnless("count-mutable-files: 1" in lines)
@@ -862,12 +821,8 @@ class DeepCheckWebGood(DeepCheckBase, unittest.TestCase):
         return d
 
     def do_cli_stats2(self):
-        basedir = self.get_clientdir(0)
-        d = self._run_cli(["--node-directory", basedir,
-                           "stats",
-                           "--raw",
-                           self.root_uri])
-        def _check4((out,err)):
+        d = self.do_cli("stats", "--raw", self.root_uri)
+        def _check4((rc,out,err)):
             data = simplejson.loads(out)
             self.failUnlessEqual(data["count-immutable-files"], 1)
             self.failUnlessEqual(data["count-immutable-files"], 1)
@@ -983,20 +938,14 @@ class DeepCheckWebBad(DeepCheckBase, unittest.TestCase):
 
         return d
 
-    def _run_cli(self, argv):
-        stdout, stderr = StringIO(), StringIO()
-        # this can only do synchronous operations
-        assert argv[0] == "debug"
-        runner.runner(argv, run_by_human=False, stdout=stdout, stderr=stderr)
-        return stdout.getvalue()
-
     def _delete_some_shares(self, node):
         self.delete_shares_numbered(node.get_uri(), [0,1])
 
+    @defer.inlineCallbacks
     def _corrupt_some_shares(self, node):
         for (shnum, serverid, sharefile) in self.find_uri_shares(node.get_uri()):
             if shnum in (0,1):
-                self._run_cli(["debug", "corrupt-share", sharefile])
+                yield run_cli("debug", "corrupt-share", sharefile)
 
     def _delete_most_shares(self, node):
         self.delete_shares_numbered(node.get_uri(), range(1,10))
diff --git a/src/allmydata/test/test_encodingutil.py b/src/allmydata/test/test_encodingutil.py
index 0632bea03..a5152c3e0 100644
--- a/src/allmydata/test/test_encodingutil.py
+++ b/src/allmydata/test/test_encodingutil.py
@@ -71,7 +71,7 @@ from allmydata.util.encodingutil import argv_to_unicode, unicode_to_url, \
     get_io_encoding, get_filesystem_encoding, to_str, from_utf8_or_none, _reload, \
     to_filepath, extend_filepath, unicode_from_filepath, unicode_segments_from
 from allmydata.dirnode import normalize
-
+from .common_util import skip_if_cannot_represent_filename
 from twisted.python import usage
 
 
@@ -265,16 +265,8 @@ class StdlibUnicode(unittest.TestCase):
     """This mainly tests that some of the stdlib functions support Unicode paths, but also that
     listdir_unicode works for valid filenames."""
 
-    def skip_if_cannot_represent_filename(self, u):
-        enc = get_filesystem_encoding()
-        if not unicode_platform():
-            try:
-                u.encode(enc)
-            except UnicodeEncodeError:
-                raise unittest.SkipTest("A non-ASCII filename could not be encoded on this platform.")
-
     def test_mkdir_open_exists_abspath_listdir_expanduser(self):
-        self.skip_if_cannot_represent_filename(lumiere_nfc)
+        skip_if_cannot_represent_filename(lumiere_nfc)
 
         try:
             os.mkdir(lumiere_nfc)
diff --git a/src/allmydata/test/test_runner.py b/src/allmydata/test/test_runner.py
index b60d83689..e8468ca46 100644
--- a/src/allmydata/test/test_runner.py
+++ b/src/allmydata/test/test_runner.py
@@ -1,5 +1,4 @@
 import os.path, re, sys, subprocess
-from cStringIO import StringIO
 
 from twisted.trial import unittest
 
@@ -10,11 +9,11 @@ from twisted.internet.defer import inlineCallbacks, returnValue
 from allmydata.util import fileutil, pollmixin
 from allmydata.util.encodingutil import unicode_to_argv, unicode_to_output, \
     get_filesystem_encoding
-from allmydata.scripts import runner
 from allmydata.client import Client
 from allmydata.test import common_util
 import allmydata
 from allmydata import __appname__
+from .common_util import parse_cli, run_cli
 
 
 timeout = 240
@@ -180,11 +179,7 @@ class CreateNode(unittest.TestCase):
         fileutil.make_dirs(basedir)
         return basedir
 
-    def run_tahoe(self, argv):
-        out,err = StringIO(), StringIO()
-        rc = runner.runner(argv, stdout=out, stderr=err)
-        return rc, out.getvalue(), err.getvalue()
-
+    @inlineCallbacks
     def do_create(self, kind, *args):
         basedir = self.workdir("test_" + kind)
         command = "create-" + kind
@@ -193,7 +188,7 @@ class CreateNode(unittest.TestCase):
 
         n1 = os.path.join(basedir, command + "-n1")
         argv = ["--quiet", command, "--basedir", n1] + list(args)
-        rc, out, err = self.run_tahoe(argv)
+        rc, out, err = yield run_cli(*argv)
         self.failUnlessEqual(err, "")
         self.failUnlessEqual(out, "")
         self.failUnlessEqual(rc, 0)
@@ -213,7 +208,7 @@ class CreateNode(unittest.TestCase):
                 self.failUnless("\nreserved_space = 1G\n" in content)
 
         # creating the node a second time should be rejected
-        rc, out, err = self.run_tahoe(argv)
+        rc, out, err = yield run_cli(*argv)
         self.failIfEqual(rc, 0, str((out, err, rc)))
         self.failUnlessEqual(out, "")
         self.failUnless("is not empty." in err)
@@ -226,7 +221,7 @@ class CreateNode(unittest.TestCase):
         # test that the non --basedir form works too
         n2 = os.path.join(basedir, command + "-n2")
         argv = ["--quiet", command] + list(args) + [n2]
-        rc, out, err = self.run_tahoe(argv)
+        rc, out, err = yield run_cli(*argv)
         self.failUnlessEqual(err, "")
         self.failUnlessEqual(out, "")
         self.failUnlessEqual(rc, 0)
@@ -236,7 +231,7 @@ class CreateNode(unittest.TestCase):
         # test the --node-directory form
         n3 = os.path.join(basedir, command + "-n3")
         argv = ["--quiet", "--node-directory", n3, command] + list(args)
-        rc, out, err = self.run_tahoe(argv)
+        rc, out, err = yield run_cli(*argv)
         self.failUnlessEqual(err, "")
         self.failUnlessEqual(out, "")
         self.failUnlessEqual(rc, 0)
@@ -247,7 +242,7 @@ class CreateNode(unittest.TestCase):
             # test that the output (without --quiet) includes the base directory
             n4 = os.path.join(basedir, command + "-n4")
             argv = [command] + list(args) + [n4]
-            rc, out, err = self.run_tahoe(argv)
+            rc, out, err = yield run_cli(*argv)
             self.failUnlessEqual(err, "")
             self.failUnlessIn(" created in ", out)
             self.failUnlessIn(n4, out)
@@ -257,18 +252,14 @@ class CreateNode(unittest.TestCase):
             self.failUnless(os.path.exists(os.path.join(n4, tac)))
 
         # make sure it rejects too many arguments
-        argv = [command, "basedir", "extraarg"]
-        self.failUnlessRaises(usage.UsageError,
-                              runner.runner, argv,
-                              run_by_human=False)
+        self.failUnlessRaises(usage.UsageError, parse_cli,
+                              command, "basedir", "extraarg")
 
         # when creating a non-client, there is no default for the basedir
         if not is_client:
             argv = [command]
-            self.failUnlessRaises(usage.UsageError,
-                                  runner.runner, argv,
-                                  run_by_human=False)
-
+            self.failUnlessRaises(usage.UsageError, parse_cli,
+                                  command)
 
     def test_node(self):
         self.do_create("node")
@@ -285,49 +276,42 @@ class CreateNode(unittest.TestCase):
 
     def test_subcommands(self):
         # no arguments should trigger a command listing, via UsageError
-        self.failUnlessRaises(usage.UsageError,
-                              runner.runner,
-                              [],
-                              run_by_human=False)
+        self.failUnlessRaises(usage.UsageError, parse_cli,
+                              )
 
+    @inlineCallbacks
     def test_stats_gatherer_good_args(self):
-        rc = runner.runner(["create-stats-gatherer", "--hostname=foo",
-                            self.mktemp()])
+        rc,out,err = yield run_cli("create-stats-gatherer", "--hostname=foo",
+                                   self.mktemp())
         self.assertEqual(rc, 0)
-        rc = runner.runner(["create-stats-gatherer", "--location=tcp:foo:1234",
-                            "--port=tcp:1234", self.mktemp()])
+        rc,out,err = yield run_cli("create-stats-gatherer",
+                                   "--location=tcp:foo:1234",
+                                   "--port=tcp:1234", self.mktemp())
         self.assertEqual(rc, 0)
 
+
     def test_stats_gatherer_bad_args(self):
+        def _test(args):
+            argv = args.split()
+            self.assertRaises(usage.UsageError, parse_cli, *argv)
+
         # missing hostname/location/port
-        argv = "create-stats-gatherer D"
-        self.assertRaises(usage.UsageError, runner.runner, argv.split(),
-                          run_by_human=False)
+        _test("create-stats-gatherer D")
 
         # missing port
-        argv = "create-stats-gatherer --location=foo D"
-        self.assertRaises(usage.UsageError, runner.runner, argv.split(),
-                          run_by_human=False)
+        _test("create-stats-gatherer --location=foo D")
 
         # missing location
-        argv = "create-stats-gatherer --port=foo D"
-        self.assertRaises(usage.UsageError, runner.runner, argv.split(),
-                          run_by_human=False)
+        _test("create-stats-gatherer --port=foo D")
 
         # can't provide both
-        argv = "create-stats-gatherer --hostname=foo --port=foo D"
-        self.assertRaises(usage.UsageError, runner.runner, argv.split(),
-                          run_by_human=False)
+        _test("create-stats-gatherer --hostname=foo --port=foo D")
 
         # can't provide both
-        argv = "create-stats-gatherer --hostname=foo --location=foo D"
-        self.assertRaises(usage.UsageError, runner.runner, argv.split(),
-                          run_by_human=False)
+        _test("create-stats-gatherer --hostname=foo --location=foo D")
 
         # can't provide all three
-        argv = "create-stats-gatherer --hostname=foo --location=foo --port=foo D"
-        self.assertRaises(usage.UsageError, runner.runner, argv.split(),
-                          run_by_human=False)
+        _test("create-stats-gatherer --hostname=foo --location=foo --port=foo D")
 
 class RunNode(common_util.SignalMixin, unittest.TestCase, pollmixin.PollMixin,
               RunBinTahoeMixin):
diff --git a/src/allmydata/test/test_system.py b/src/allmydata/test/test_system.py
index 57af07139..3d4004e6e 100644
--- a/src/allmydata/test/test_system.py
+++ b/src/allmydata/test/test_system.py
@@ -1,10 +1,8 @@
 
 import os, re, sys, time, simplejson
-from cStringIO import StringIO
 
 from twisted.trial import unittest
 from twisted.internet import defer
-from twisted.internet import threads # CLI tests use deferToThread
 from twisted.application import service
 
 import allmydata
@@ -20,7 +18,6 @@ from allmydata.util import log, base32
 from allmydata.util.encodingutil import quote_output, unicode_to_argv
 from allmydata.util.fileutil import abspath_expanduser_unicode
 from allmydata.util.consumer import MemoryConsumer, download_to_data
-from allmydata.scripts import runner
 from allmydata.stats import StatsGathererService
 from allmydata.interfaces import IDirectoryNode, IFileNode, \
      NoSuchChildError, NoSharesError
@@ -39,6 +36,7 @@ from .common import TEST_RSA_KEY_SIZE
 # TODO: move this to common or common_util
 from allmydata.test.test_runner import RunBinTahoeMixin
 from . import common_util as testutil
+from .common_util import run_cli
 
 LARGE_DATA = """
 This is some data to publish to the remote grid.., which needs to be large
@@ -1064,6 +1062,7 @@ class SystemTest(SystemTestMixin, RunBinTahoeMixin, unittest.TestCase):
             return d1
         d.addCallback(_create_mutable)
 
+        @defer.inlineCallbacks
         def _test_debug(res):
             # find a share. It is important to run this while there is only
             # one slot in the grid.
@@ -1073,11 +1072,8 @@ class SystemTest(SystemTestMixin, RunBinTahoeMixin, unittest.TestCase):
                     % filename)
             log.msg(" for clients[%d]" % client_num)
 
-            out,err = StringIO(), StringIO()
-            rc = runner.runner(["debug", "dump-share", "--offsets",
-                                filename],
-                               stdout=out, stderr=err)
-            output = out.getvalue()
+            rc,output,err = yield run_cli("debug", "dump-share", "--offsets",
+                                          filename)
             self.failUnlessEqual(rc, 0)
             try:
                 self.failUnless("Mutable slot found:\n" in output)
@@ -1862,6 +1858,7 @@ class SystemTest(SystemTestMixin, RunBinTahoeMixin, unittest.TestCase):
 
         return d
 
+    @defer.inlineCallbacks
     def _test_runner(self, res):
         # exercise some of the diagnostic tools in runner.py
 
@@ -1887,11 +1884,8 @@ class SystemTest(SystemTestMixin, RunBinTahoeMixin, unittest.TestCase):
                       % self.basedir)
         log.msg("test_system.SystemTest._test_runner using %r" % filename)
 
-        out,err = StringIO(), StringIO()
-        rc = runner.runner(["debug", "dump-share", "--offsets",
-                            unicode_to_argv(filename)],
-                           stdout=out, stderr=err)
-        output = out.getvalue()
+        rc,output,err = yield run_cli("debug", "dump-share", "--offsets",
+                                      unicode_to_argv(filename))
         self.failUnlessEqual(rc, 0)
 
         # we only upload a single file, so we can assert some things about
@@ -1917,23 +1911,18 @@ class SystemTest(SystemTestMixin, RunBinTahoeMixin, unittest.TestCase):
         sharedir, shnum = os.path.split(filename)
         storagedir, storage_index_s = os.path.split(sharedir)
         storage_index_s = str(storage_index_s)
-        out,err = StringIO(), StringIO()
         nodedirs = [self.getdir("client%d" % i) for i in range(self.numclients)]
-        cmd = ["debug", "find-shares", storage_index_s] + nodedirs
-        rc = runner.runner(cmd, stdout=out, stderr=err)
+        rc,out,err = yield run_cli("debug", "find-shares", storage_index_s,
+                                   *nodedirs)
         self.failUnlessEqual(rc, 0)
-        out.seek(0)
-        sharefiles = [sfn.strip() for sfn in out.readlines()]
+        sharefiles = [sfn.strip() for sfn in out.splitlines()]
         self.failUnlessEqual(len(sharefiles), 10)
 
         # also exercise the 'catalog-shares' tool
-        out,err = StringIO(), StringIO()
         nodedirs = [self.getdir("client%d" % i) for i in range(self.numclients)]
-        cmd = ["debug", "catalog-shares"] + nodedirs
-        rc = runner.runner(cmd, stdout=out, stderr=err)
+        rc,out,err = yield run_cli("debug", "catalog-shares", *nodedirs)
         self.failUnlessEqual(rc, 0)
-        out.seek(0)
-        descriptions = [sfn.strip() for sfn in out.readlines()]
+        descriptions = [sfn.strip() for sfn in out.splitlines()]
         self.failUnlessEqual(len(descriptions), 30)
         matching = [line
                     for line in descriptions
@@ -1981,10 +1970,10 @@ class SystemTest(SystemTestMixin, RunBinTahoeMixin, unittest.TestCase):
         f.write(private_uri)
         f.close()
 
+        @defer.inlineCallbacks
         def run(ignored, verb, *args, **kwargs):
-            stdin = kwargs.get("stdin", "")
-            newargs = nodeargs + [verb] + list(args)
-            return self._run_cli(newargs, stdin=stdin)
+            rc,out,err = yield run_cli(verb, *args, nodeargs=nodeargs, **kwargs)
+            defer.returnValue((out,err))
 
         def _check_ls((out,err), expected_children, unexpected_children=[]):
             self.failUnlessEqual(err, "")
@@ -2345,17 +2334,6 @@ class SystemTest(SystemTestMixin, RunBinTahoeMixin, unittest.TestCase):
         d.addCallback(_check_ls)
         return d
 
-    def _run_cli(self, argv, stdin=""):
-        #print "CLI:", argv
-        stdout, stderr = StringIO(), StringIO()
-        d = threads.deferToThread(runner.runner, argv, run_by_human=False,
-                                  stdin=StringIO(stdin),
-                                  stdout=stdout, stderr=stderr)
-        def _done(res):
-            return stdout.getvalue(), stderr.getvalue()
-        d.addCallback(_done)
-        return d
-
     def _test_checker(self, res):
         ut = upload.Data("too big to be literal" * 200, convergence=None)
         d = self._personal_node.add_file(u"big file", ut)