address some review comments

flocker/node/_docker.py

@@ -208,13 +208,14 @@ def exists(unit_name):
             otherwise ``False``.
         """
 
-    def remove(unit_name):
+    def remove(unit_name, force):
         """
         Stop and delete the given unit.
 
         This can be done multiple times in a row for the same unit.
 
         :param unicode unit_name: The name of the unit to stop.
+        :param bool force: Force removal of the unit.
 
         :return: ``Deferred`` that fires once the unit has been stopped
             and removed.
@@ -271,7 +272,7 @@ def add(self, unit_name, image_name, ports=frozenset(), environment=None,
     def exists(self, unit_name):
         return succeed(unit_name in self._units)
 
-    def remove(self, unit_name):
+    def remove(self, unit_name, force=False):
         if unit_name in self._units:
             del self._units[unit_name]
         return succeed(None)

flocker/node/functional/test_docker.py

@@ -150,7 +150,7 @@ def test_force_remove(self):
         expected_states = (u'active',)
         d = client.add(
             unit_name=unit_name,
-            image_name=u'clusterhq/flask'
+            image_name=u"openshift/busybox-http-app"
         )
         d.addCallback(
             lambda _: wait_for_unit_state(
@@ -162,7 +162,7 @@ def check_is_listed(_):
             listed = client.list()
 
             def check_unit(results):
-                self.assertTrue(unit_name in [unit.name for unit in results])
+                self.assertIn(unit_name, [unit.name for unit in results])
             listed.addCallback(check_unit)
             return listed
 
@@ -173,7 +173,7 @@ def check_is_removed(_):
             listed = client.list()
 
             def check_unit(results):
-                self.assertFalse(unit_name in [unit.name for unit in results])
+                self.assertNotIn(unit_name, [unit.name for unit in results])
             listed.addCallback(check_unit)
             return listed
 

flocker/node/test/test_docker.py

@@ -117,6 +117,31 @@ def test_removed_does_not_exist(self):
             d.addCallback(self.assertFalse)
             return d
 
+        def test_forced_removed_does_not_exist(self):
+            """
+            A container removed with the ``force`` switch does not exist.
+            """
+            client = fixture(self)
+            name = random_name(self)
+            image = u"openshift/busybox-http-app"
+            d = client.add(name, image)
+            d.addCallback(lambda _: client.list())
+            expected = Unit(
+                name=name, container_name=name, activation_state=u"active",
+                container_image=image,
+            )
+
+            def got_units(units):
+                result = units.pop()
+                result = result.set("container_name", name)
+                self.assertEqual(expected, result)
+
+            d.addCallback(got_units)
+            d.addCallback(lambda _: client.remove(name, force=True))
+            d.addCallback(lambda _: client.exists(name))
+            d.addCallback(self.assertFalse)
+            return d
+
         def test_added_is_listed(self):
             """
             An added container is included in the output of ``list()``.