factor cleanup into api class

src/allmydata/test/cli_node_api.py

@@ -26,7 +26,12 @@ from twisted.internet.defer import (
     succeed,
 )
 
-from allmydata.client import _Client
+from ..client import (
+    _Client,
+)
+from ..scripts.tahoe_stop import (
+    COULD_NOT_STOP,
+)
 
 class Expect(Protocol):
     def __init__(self):
@@ -134,6 +139,20 @@ class CLINodeAPI(object):
         # the test fails), the client should still terminate.
         self.exit_trigger_file.touch()
 
+    def cleanup(self):
+        stopping = stop_and_wait(tahoe)
+        stopping.addErrback(
+            # Let it fail because the process has already exited.
+            lambda err: (
+                err.trap(ProcessTerminated)
+                and self.assertEqual(
+                    err.value.exitCode,
+                    COULD_NOT_STOP,
+                )
+            )
+        )
+        return stopping
+
 
 class _WaitForEnd(ProcessProtocol):
     def __init__(self, ended):

src/allmydata/test/test_runner.py

@@ -41,9 +41,6 @@ from ._twisted_9607 import (
 from ..util.eliotutil import (
     inline_callbacks,
 )
-from ..scripts.tahoe_stop import (
-    COULD_NOT_STOP,
-)
 
 timeout = 240
 
@@ -614,18 +611,7 @@ class RunNode(common_util.SignalMixin, unittest.TestCase, pollmixin.PollMixin,
 
         tahoe = CLINodeAPI(reactor, FilePath(c1))
         # Set this up right now so we don't forget later.
-        self.addCleanup(
-            lambda: stop_and_wait(tahoe).addErrback(
-                # Let it fail because the process has already exited.
-                lambda err: (
-                    err.trap(ProcessTerminated)
-                    and self.assertEqual(
-                        err.value.exitCode,
-                        COULD_NOT_STOP,
-                    )
-                )
-            )
-        )
+        self.addCleanup(tahoe.cleanup)
 
         out, err, rc_or_sig = yield self.run_bintahoe([
             "--quiet", "create-node", "--basedir", c1,