4 files changed, 37 insertions, 19 deletions
diff --git a/src/mailman/app/subscriptions.py b/src/mailman/app/subscriptions.py
index 90811722d..c89e1e79f 100644
--- a/src/mailman/app/subscriptions.py
+++ b/src/mailman/app/subscriptions.py
@@ -28,10 +28,10 @@ from mailman.interfaces.subscriptions import (
 from mailman.interfaces.template import ITemplateLoader
 from mailman.interfaces.workflows import IWorkflowStateManager
 from mailman.utilities.string import expand
-from mailman.workflows.builtin import (PendableSubscription,
-                                       PendableUnsubscription,
-                                       SubscriptionWorkflow,
+from mailman.workflows.builtin import (SubscriptionWorkflow,
                                        UnSubscriptionWorkflow)
+from mailman.workflows.common import (PendableSubscription,
+                                      PendableUnsubscription)
 from public import public
 from zope.component import getUtility
 from zope.interface import implementer
diff --git a/src/mailman/workflows/base.py b/src/mailman/workflows/base.py
index 5988dfa43..e374d58b4 100644
--- a/src/mailman/workflows/base.py
+++ b/src/mailman/workflows/base.py
@@ -23,9 +23,11 @@ import logging
 
 from collections import deque
 
-from mailman.interfaces.workflows import IWorkflowStateManager
+from mailman.interfaces.workflows import IWorkflow, IWorkflowStateManager
+from mailman.utilities.modules import abstract_component
 from public import public
 from zope.component import getUtility
+from zope.interface import implementer
 
 
 COMMASPACE = ', '
@@ -33,6 +35,8 @@ log = logging.getLogger('mailman.error')
 
 
 @public
+@abstract_component
+@implementer(IWorkflow)
 class Workflow:
     """Generic workflow."""
 
diff --git a/src/mailman/workflows/builtin.py b/src/mailman/workflows/builtin.py
index e16a888fc..33e428d0b 100644
--- a/src/mailman/workflows/builtin.py
+++ b/src/mailman/workflows/builtin.py
@@ -29,13 +29,15 @@ from mailman.interfaces.mailinglist import SubscriptionPolicy
 from mailman.interfaces.member import (AlreadySubscribedError, MemberRole,
                                        MembershipIsBannedError,
                                        NotAMemberError)
-from mailman.interfaces.pending import IPendable, IPendings
+from mailman.interfaces.pending import IPendings
 from mailman.interfaces.subscriptions import (
     SubscriptionConfirmationNeededEvent, SubscriptionPendingError,
     TokenOwner, UnsubscriptionConfirmationNeededEvent)
 from mailman.interfaces.template import ITemplateLoader
 from mailman.interfaces.user import IUser
 from mailman.interfaces.usermanager import IUserManager
+from mailman.interfaces.workflows import (ISubscriptionWorkflow,
+                                          IUnsubscriptionWorkflow)
 from mailman.utilities.datetime import now
 from mailman.utilities.string import expand, wrap
 from mailman.workflows.common import (SubscriptionWorkflowCommon,
@@ -49,17 +51,8 @@ from zope.interface import implementer
 log = logging.getLogger('mailman.subscribe')
 
 
-@implementer(IPendable)
-class PendableSubscription(dict):
-    PEND_TYPE = 'subscription'
-
-
-@implementer(IPendable)
-class PendableUnsubscription(dict):
-    PEND_TYPE = 'unsubscription'
-
-
 @public
+@implementer(ISubscriptionWorkflow)
 class SubscriptionWorkflow(SubscriptionWorkflowCommon):
     """Workflow of a subscription request."""
 
@@ -269,6 +262,7 @@ class SubscriptionWorkflow(SubscriptionWorkflowCommon):
 
 
 @public
+@implementer(IUnsubscriptionWorkflow)
 class UnSubscriptionWorkflow(SubscriptionWorkflowCommon):
     """Workflow of a unsubscription request."""
 
diff --git a/src/mailman/workflows/common.py b/src/mailman/workflows/common.py
index 940152272..c57ce374d 100644
--- a/src/mailman/workflows/common.py
+++ b/src/mailman/workflows/common.py
@@ -22,13 +22,17 @@ import uuid
 from datetime import timedelta
 from enum import Enum
 from mailman.interfaces.address import IAddress
-from mailman.interfaces.pending import IPendings
+from mailman.interfaces.pending import IPendable, IPendings
 from mailman.interfaces.subscriptions import TokenOwner
 from mailman.interfaces.user import IUser
 from mailman.interfaces.usermanager import IUserManager
+from mailman.interfaces.workflows import (ISubscriptionWorkflow,
+                                          IUnsubscriptionWorkflow, IWorkflow)
 from mailman.utilities.datetime import now
 from mailman.workflows.base import Workflow
 from zope.component import getUtility
+from zope.interface import implementer
+from zope.interface.exceptions import DoesNotImplement
 
 
 class WhichSubscriber(Enum):
@@ -36,11 +40,19 @@ class WhichSubscriber(Enum):
     user = 2
 
 
+@implementer(IPendable)
+class PendableSubscription(dict):
+    PEND_TYPE = 'subscription'
+
+
+@implementer(IPendable)
+class PendableUnsubscription(dict):
+    PEND_TYPE = 'unsubscription'
+
+
 class SubscriptionWorkflowCommon(Workflow):
     """Common support between subscription and unsubscription."""
 
-    PENDABLE_CLASS = None
-
     def __init__(self, mlist, subscriber):
         super().__init__()
         self.mlist = mlist
@@ -113,7 +125,15 @@ class SubscriptionWorkflowCommon(Workflow):
         if token_owner is TokenOwner.no_one:
             self.token = None
             return
-        pendable = self.PENDABLE_CLASS(
+
+        if ISubscriptionWorkflow.implementedBy(self.__class__):
+            pendable_class = PendableSubscription
+        elif IUnsubscriptionWorkflow.implementedBy(self.__class__):
+            pendable_class = PendableUnsubscription
+        else:
+            raise DoesNotImplement(IWorkflow)
+
+        pendable = pendable_class(
             list_id=self.mlist.list_id,
             email=self.address.email,
             display_name=self.address.display_name,