Add module API callbacks for adding and deleting local 3PID associations (#15044

12 files changed, 324 insertions, 48 deletions

diff --git a/changelog.d/15044.feature b/changelog.d/15044.feature
new file mode 100644
index 0000000000..91e5cda8c3
--- /dev/null
+++ b/changelog.d/15044.feature
@@ -0,0 +1 @@
+Add two new Third Party Rules module API callbacks: [`on_add_user_third_party_identifier`](https://matrix-org.github.io/synapse/v1.79/modules/third_party_rules_callbacks.html#on_add_user_third_party_identifier) and [`on_remove_user_third_party_identifier`](https://matrix-org.github.io/synapse/v1.79/modules/third_party_rules_callbacks.html#on_remove_user_third_party_identifier).
\ No newline at end of file
diff --git a/docs/modules/third_party_rules_callbacks.md b/docs/modules/third_party_rules_callbacks.md
index 888e43bd10..4a27d976fb 100644
--- a/docs/modules/third_party_rules_callbacks.md
+++ b/docs/modules/third_party_rules_callbacks.md
@@ -254,6 +254,11 @@ If multiple modules implement this callback, Synapse runs them all in order.
 
 _First introduced in Synapse v1.56.0_
 
+**<span style="color:red">
+This callback is deprecated in favour of the `on_add_user_third_party_identifier` callback, which
+features the same functionality. The only difference is in name.
+</span>**
+
 ```python
 async def on_threepid_bind(user_id: str, medium: str, address: str) -> None:
 ```
@@ -268,6 +273,44 @@ server_.
 
 If multiple modules implement this callback, Synapse runs them all in order.
 
+### `on_add_user_third_party_identifier`
+
+_First introduced in Synapse v1.79.0_
+
+```python
+async def on_add_user_third_party_identifier(user_id: str, medium: str, address: str) -> None:
+```
+
+Called after successfully creating an association between a user and a third-party identifier
+(email address, phone number). The module is given the Matrix ID of the user the
+association is for, as well as the medium (`email` or `msisdn`) and address of the
+third-party identifier (i.e. an email address).
+
+Note that this callback is _not_ called if a user attempts to bind their third-party identifier
+to an identity server (via a call to [`POST
+/_matrix/client/v3/account/3pid/bind`](https://spec.matrix.org/v1.5/client-server-api/#post_matrixclientv3account3pidbind)).
+
+If multiple modules implement this callback, Synapse runs them all in order.
+
+### `on_remove_user_third_party_identifier`
+
+_First introduced in Synapse v1.79.0_
+
+```python
+async def on_remove_user_third_party_identifier(user_id: str, medium: str, address: str) -> None:
+```
+
+Called after successfully removing an association between a user and a third-party identifier
+(email address, phone number). The module is given the Matrix ID of the user the
+association is for, as well as the medium (`email` or `msisdn`) and address of the
+third-party identifier (i.e. an email address).
+
+Note that this callback is _not_ called if a user attempts to unbind their third-party
+identifier from an identity server (via a call to [`POST
+/_matrix/client/v3/account/3pid/unbind`](https://spec.matrix.org/v1.5/client-server-api/#post_matrixclientv3account3pidunbind)).
+
+If multiple modules implement this callback, Synapse runs them all in order.
+
 ## Example
 
 The example below is a module that implements the third-party rules callback
@@ -300,4 +343,4 @@ class EventCensorer:
         )
         event_dict["content"] = new_event_content
         return event_dict
-```
+```
\ No newline at end of file
diff --git a/docs/upgrade.md b/docs/upgrade.md
index 15167b8c58..f06e874054 100644
--- a/docs/upgrade.md
+++ b/docs/upgrade.md
@@ -88,6 +88,30 @@ process, for example:
     dpkg -i matrix-synapse-py3_1.3.0+stretch1_amd64.deb
     ```
 
+# Upgrading to v1.79.0
+
+## The `on_threepid_bind` module callback method has been deprecated
+
+Synapse v1.79.0 deprecates the
+[`on_threepid_bind`](modules/third_party_rules_callbacks.md#on_threepid_bind)
+"third-party rules" Synapse module callback method in favour of a new module method,
+[`on_add_user_third_party_identifier`](modules/third_party_rules_callbacks.md#on_add_user_third_party_identifier).
+`on_threepid_bind` will be removed in a future version of Synapse. You should check whether any Synapse
+modules in use in your deployment are making use of `on_threepid_bind`, and update them where possible.
+
+The arguments and functionality of the new method are the same.
+
+The justification behind the name change is that the old method's name, `on_threepid_bind`, was
+misleading. A user is considered to "bind" their third-party ID to their Matrix ID only if they
+do so via an [identity server](https://spec.matrix.org/latest/identity-service-api/)
+(so that users on other homeservers may find them). But this method was not called in that case -
+it was only called when a user added a third-party identifier on the local homeserver.
+
+Module developers may also be interested in the related
+[`on_remove_user_third_party_identifier`](modules/third_party_rules_callbacks.md#on_remove_user_third_party_identifier)
+module callback method that was also added in Synapse v1.79.0. This new method is called when a
+user removes a third-party identifier from their account.
+
 # Upgrading to v1.78.0
 
 ## Deprecate the `/_synapse/admin/v1/media/<server_name>/delete` admin API
diff --git a/synapse/events/third_party_rules.py b/synapse/events/third_party_rules.py
index 9a25ed419b..3e4d52c8d8 100644
--- a/synapse/events/third_party_rules.py
+++ b/synapse/events/third_party_rules.py
@@ -45,6 +45,8 @@ CHECK_CAN_DEACTIVATE_USER_CALLBACK = Callable[[str, bool], Awaitable[bool]]
 ON_PROFILE_UPDATE_CALLBACK = Callable[[str, ProfileInfo, bool, bool], Awaitable]
 ON_USER_DEACTIVATION_STATUS_CHANGED_CALLBACK = Callable[[str, bool, bool], Awaitable]
 ON_THREEPID_BIND_CALLBACK = Callable[[str, str, str], Awaitable]
+ON_ADD_USER_THIRD_PARTY_IDENTIFIER_CALLBACK = Callable[[str, str, str], Awaitable]
+ON_REMOVE_USER_THIRD_PARTY_IDENTIFIER_CALLBACK = Callable[[str, str, str], Awaitable]
 
 
 def load_legacy_third_party_event_rules(hs: "HomeServer") -> None:
@@ -172,6 +174,12 @@ class ThirdPartyEventRules:
             ON_USER_DEACTIVATION_STATUS_CHANGED_CALLBACK
         ] = []
         self._on_threepid_bind_callbacks: List[ON_THREEPID_BIND_CALLBACK] = []
+        self._on_add_user_third_party_identifier_callbacks: List[
+            ON_ADD_USER_THIRD_PARTY_IDENTIFIER_CALLBACK
+        ] = []
+        self._on_remove_user_third_party_identifier_callbacks: List[
+            ON_REMOVE_USER_THIRD_PARTY_IDENTIFIER_CALLBACK
+        ] = []
 
     def register_third_party_rules_callbacks(
         self,
@@ -191,6 +199,12 @@ class ThirdPartyEventRules:
             ON_USER_DEACTIVATION_STATUS_CHANGED_CALLBACK
         ] = None,
         on_threepid_bind: Optional[ON_THREEPID_BIND_CALLBACK] = None,
+        on_add_user_third_party_identifier: Optional[
+            ON_ADD_USER_THIRD_PARTY_IDENTIFIER_CALLBACK
+        ] = None,
+        on_remove_user_third_party_identifier: Optional[
+            ON_REMOVE_USER_THIRD_PARTY_IDENTIFIER_CALLBACK
+        ] = None,
     ) -> None:
         """Register callbacks from modules for each hook."""
         if check_event_allowed is not None:
@@ -228,6 +242,11 @@ class ThirdPartyEventRules:
         if on_threepid_bind is not None:
             self._on_threepid_bind_callbacks.append(on_threepid_bind)
 
+        if on_add_user_third_party_identifier is not None:
+            self._on_add_user_third_party_identifier_callbacks.append(
+                on_add_user_third_party_identifier
+            )
+
     async def check_event_allowed(
         self,
         event: EventBase,
@@ -511,6 +530,9 @@ class ThirdPartyEventRules:
         local homeserver, not when it's created on an identity server (and then kept track
         of so that it can be unbound on the same IS later on).
 
+        THIS MODULE CALLBACK METHOD HAS BEEN DEPRECATED. Please use the
+        `on_add_user_third_party_identifier` callback method instead.
+
         Args:
             user_id: the user being associated with the threepid.
             medium: the threepid's medium.
@@ -523,3 +545,44 @@ class ThirdPartyEventRules:
                 logger.exception(
                     "Failed to run module API callback %s: %s", callback, e
                 )
+
+    async def on_add_user_third_party_identifier(
+        self, user_id: str, medium: str, address: str
+    ) -> None:
+        """Called when an association between a user's Matrix ID and a third-party ID
+        (email, phone number) has successfully been registered on the homeserver.
+
+        Args:
+            user_id: The User ID included in the association.
+            medium: The medium of the third-party ID (email, msisdn).
+            address: The address of the third-party ID (i.e. an email address).
+        """
+        for callback in self._on_add_user_third_party_identifier_callbacks:
+            try:
+                await callback(user_id, medium, address)
+            except Exception as e:
+                logger.exception(
+                    "Failed to run module API callback %s: %s", callback, e
+                )
+
+    async def on_remove_user_third_party_identifier(
+        self, user_id: str, medium: str, address: str
+    ) -> None:
+        """Called when an association between a user's Matrix ID and a third-party ID
+        (email, phone number) has been successfully removed on the homeserver.
+
+        This is called *after* any known bindings on identity servers for this
+        association have been removed.
+
+        Args:
+            user_id: The User ID included in the removed association.
+            medium: The medium of the third-party ID (email, msisdn).
+            address: The address of the third-party ID (i.e. an email address).
+        """
+        for callback in self._on_remove_user_third_party_identifier_callbacks:
+            try:
+                await callback(user_id, medium, address)
+            except Exception as e:
+                logger.exception(
+                    "Failed to run module API callback %s: %s", callback, e
+                )
diff --git a/synapse/handlers/auth.py b/synapse/handlers/auth.py
index b12bc4c9a3..308e38edea 100644
--- a/synapse/handlers/auth.py
+++ b/synapse/handlers/auth.py
@@ -1542,6 +1542,17 @@ class AuthHandler:
     async def add_threepid(
         self, user_id: str, medium: str, address: str, validated_at: int
     ) -> None:
+        """
+        Adds an association between a user's Matrix ID and a third-party ID (email,
+        phone number).
+
+        Args:
+            user_id: The ID of the user to associate.
+            medium: The medium of the third-party ID (email, msisdn).
+            address: The address of the third-party ID (i.e. an email address).
+            validated_at: The timestamp in ms of when the validation that the user owns
+                this third-party ID occurred.
+        """
         # check if medium has a valid value
         if medium not in ["email", "msisdn"]:
             raise SynapseError(
@@ -1566,42 +1577,44 @@ class AuthHandler:
             user_id, medium, address, validated_at, self.hs.get_clock().time_msec()
         )
 
+        # Inform Synapse modules that a 3PID association has been created.
+        await self._third_party_rules.on_add_user_third_party_identifier(
+            user_id, medium, address
+        )
+
+        # Deprecated method for informing Synapse modules that a 3PID association
+        # has successfully been created.
         await self._third_party_rules.on_threepid_bind(user_id, medium, address)
 
-    async def delete_threepid(
-        self, user_id: str, medium: str, address: str, id_server: Optional[str] = None
-    ) -> bool:
-        """Attempts to unbind the 3pid on the identity servers and deletes it
-        from the local database.
+    async def delete_local_threepid(
+        self, user_id: str, medium: str, address: str
+    ) -> None:
+        """Deletes an association between a third-party ID and a user ID from the local
+        database. This method does not unbind the association from any identity servers.
+
+        If `medium` is 'email' and a pusher is associated with this third-party ID, the
+        pusher will also be deleted.
 
         Args:
             user_id: ID of user to remove the 3pid from.
             medium: The medium of the 3pid being removed: "email" or "msisdn".
             address: The 3pid address to remove.
-            id_server: Use the given identity server when unbinding
-                any threepids. If None then will attempt to unbind using the
-                identity server specified when binding (if known).
-
-        Returns:
-            Returns True if successfully unbound the 3pid on
-            the identity server, False if identity server doesn't support the
-            unbind API.
         """
-
         # 'Canonicalise' email addresses as per above
         if medium == "email":
             address = canonicalise_email(address)
 
-        result = await self.hs.get_identity_handler().try_unbind_threepid(
-            user_id, medium, address, id_server
+        await self.store.user_delete_threepid(user_id, medium, address)
+
+        # Inform Synapse modules that a 3PID association has been deleted.
+        await self._third_party_rules.on_remove_user_third_party_identifier(
+            user_id, medium, address
         )
 
-        await self.store.user_delete_threepid(user_id, medium, address)
         if medium == "email":
             await self.store.delete_pusher_by_app_id_pushkey_user_id(
                 app_id="m.email", pushkey=address, user_id=user_id
             )
-        return result
 
     async def hash(self, password: str) -> str:
         """Computes a secure hash of password.
diff --git a/synapse/handlers/deactivate_account.py b/synapse/handlers/deactivate_account.py
index d24f649382..d31263c717 100644
--- a/synapse/handlers/deactivate_account.py
+++ b/synapse/handlers/deactivate_account.py
@@ -100,26 +100,28 @@ class DeactivateAccountHandler:
         # unbinding
         identity_server_supports_unbinding = True
 
-        # Retrieve the 3PIDs this user has bound to an identity server
-        threepids = await self.store.user_get_bound_threepids(user_id)
-
-        for threepid in threepids:
+        # Attempt to unbind any known bound threepids to this account from identity
+        # server(s).
+        bound_threepids = await self.store.user_get_bound_threepids(user_id)
+        for threepid in bound_threepids:
             try:
                 result = await self._identity_handler.try_unbind_threepid(
                     user_id, threepid["medium"], threepid["address"], id_server
                 )
-                identity_server_supports_unbinding &= result
             except Exception:
                 # Do we want this to be a fatal error or should we carry on?
                 logger.exception("Failed to remove threepid from ID server")
                 raise SynapseError(400, "Failed to remove threepid from ID server")
-            await self.store.user_delete_threepid(
+
+            identity_server_supports_unbinding &= result
+
+        # Remove any local threepid associations for this account.
+        local_threepids = await self.store.user_get_threepids(user_id)
+        for threepid in local_threepids:
+            await self._auth_handler.delete_local_threepid(
                 user_id, threepid["medium"], threepid["address"]
             )
 
-        # Remove all 3PIDs this user has bound to the homeserver
-        await self.store.user_delete_threepids(user_id)
-
         # delete any devices belonging to the user, which will also
         # delete corresponding access tokens.
         await self._device_handler.delete_all_devices_for_user(user_id)
diff --git a/synapse/module_api/__init__.py b/synapse/module_api/__init__.py
index 1964276a54..424239e3df 100644
--- a/synapse/module_api/__init__.py
+++ b/synapse/module_api/__init__.py
@@ -64,9 +64,11 @@ from synapse.events.third_party_rules import (
     CHECK_EVENT_ALLOWED_CALLBACK,
     CHECK_THREEPID_CAN_BE_INVITED_CALLBACK,
     CHECK_VISIBILITY_CAN_BE_MODIFIED_CALLBACK,
+    ON_ADD_USER_THIRD_PARTY_IDENTIFIER_CALLBACK,
     ON_CREATE_ROOM_CALLBACK,
     ON_NEW_EVENT_CALLBACK,
     ON_PROFILE_UPDATE_CALLBACK,
+    ON_REMOVE_USER_THIRD_PARTY_IDENTIFIER_CALLBACK,
     ON_THREEPID_BIND_CALLBACK,
     ON_USER_DEACTIVATION_STATUS_CHANGED_CALLBACK,
 )
@@ -357,6 +359,12 @@ class ModuleApi:
             ON_USER_DEACTIVATION_STATUS_CHANGED_CALLBACK
         ] = None,
         on_threepid_bind: Optional[ON_THREEPID_BIND_CALLBACK] = None,
+        on_add_user_third_party_identifier: Optional[
+            ON_ADD_USER_THIRD_PARTY_IDENTIFIER_CALLBACK
+        ] = None,
+        on_remove_user_third_party_identifier: Optional[
+            ON_REMOVE_USER_THIRD_PARTY_IDENTIFIER_CALLBACK
+        ] = None,
     ) -> None:
         """Registers callbacks for third party event rules capabilities.
 
@@ -373,6 +381,8 @@ class ModuleApi:
             on_profile_update=on_profile_update,
             on_user_deactivation_status_changed=on_user_deactivation_status_changed,
             on_threepid_bind=on_threepid_bind,
+            on_add_user_third_party_identifier=on_add_user_third_party_identifier,
+            on_remove_user_third_party_identifier=on_remove_user_third_party_identifier,
         )
 
     def register_presence_router_callbacks(
diff --git a/synapse/rest/admin/users.py b/synapse/rest/admin/users.py
index 7cc4db20d6..357e9a574d 100644
--- a/synapse/rest/admin/users.py
+++ b/synapse/rest/admin/users.py
@@ -304,13 +304,20 @@ class UserRestServletV2(RestServlet):
                 # remove old threepids
                 for medium, address in del_threepids:
                     try:
-                        await self.auth_handler.delete_threepid(
-                            user_id, medium, address, None
+                        # Attempt to remove any known bindings of this third-party ID
+                        # and user ID from identity servers.
+                        await self.hs.get_identity_handler().try_unbind_threepid(
+                            user_id, medium, address, id_server=None
                         )
                     except Exception:
                         logger.exception("Failed to remove threepids")
                         raise SynapseError(500, "Failed to remove threepids")
 
+                    # Delete the local association of this user ID and third-party ID.
+                    await self.auth_handler.delete_local_threepid(
+                        user_id, medium, address
+                    )
+
                 # add new threepids
                 current_time = self.hs.get_clock().time_msec()
                 for medium, address in add_threepids:
diff --git a/synapse/rest/client/account.py b/synapse/rest/client/account.py
index 662f5bf762..484d7440a4 100644
--- a/synapse/rest/client/account.py
+++ b/synapse/rest/client/account.py
@@ -768,7 +768,9 @@ class ThreepidDeleteRestServlet(RestServlet):
         user_id = requester.user.to_string()
 
         try:
-            ret = await self.auth_handler.delete_threepid(
+            # Attempt to remove any known bindings of this third-party ID
+            # and user ID from identity servers.
+            ret = await self.hs.get_identity_handler().try_unbind_threepid(
                 user_id, body.medium, body.address, body.id_server
             )
         except Exception:
@@ -783,6 +785,11 @@ class ThreepidDeleteRestServlet(RestServlet):
         else:
             id_server_unbind_result = "no-support"
 
+        # Delete the local association of this user ID and third-party ID.
+        await self.auth_handler.delete_local_threepid(
+            user_id, body.medium, body.address
+        )
+
         return 200, {"id_server_unbind_result": id_server_unbind_result}
 
 
diff --git a/synapse/storage/databases/main/registration.py b/synapse/storage/databases/main/registration.py
index 9a55e17624..717237e024 100644
--- a/synapse/storage/databases/main/registration.py
+++ b/synapse/storage/databases/main/registration.py
@@ -1002,19 +1002,6 @@ class RegistrationWorkerStore(CacheInvalidationWorkerStore):
             desc="user_delete_threepid",
         )
 
-    async def user_delete_threepids(self, user_id: str) -> None:
-        """Delete all threepid this user has bound
-
-        Args:
-             user_id: The user id to delete all threepids of
-
-        """
-        await self.db_pool.simple_delete(
-            "user_threepids",
-            keyvalues={"user_id": user_id},
-            desc="user_delete_threepids",
-        )
-
     async def add_user_bound_threepid(
         self, user_id: str, medium: str, address: str, id_server: str
     ) -> None:
diff --git a/tests/push/test_email.py b/tests/push/test_email.py
index 0a3aca5c50..4ea5472eb4 100644
--- a/tests/push/test_email.py
+++ b/tests/push/test_email.py
@@ -369,10 +369,8 @@ class EmailPusherTests(HomeserverTestCase):
 
         # disassociate the user's email address
         self.get_success(
-            self.auth_handler.delete_threepid(
-                user_id=self.user_id,
-                medium="email",
-                address="a@example.com",
+            self.auth_handler.delete_local_threepid(
+                user_id=self.user_id, medium="email", address="a@example.com"
             )
         )
 
diff --git a/tests/rest/client/test_third_party_rules.py b/tests/rest/client/test_third_party_rules.py
index c0f93f898a..3b99513707 100644
--- a/tests/rest/client/test_third_party_rules.py
+++ b/tests/rest/client/test_third_party_rules.py
@@ -934,3 +934,124 @@ class ThirdPartyRulesTestCase(unittest.FederatingHomeserverTestCase):
 
         # Check that the mock was called with the right parameters
         self.assertEqual(args, (user_id, "email", "foo@example.com"))
+
+    def test_on_add_and_remove_user_third_party_identifier(self) -> None:
+        """Tests that the on_add_user_third_party_identifier and
+        on_remove_user_third_party_identifier module callbacks are called
+        just before associating and removing a 3PID to/from an account.
+        """
+        # Pretend to be a Synapse module and register both callbacks as mocks.
+        third_party_rules = self.hs.get_third_party_event_rules()
+        on_add_user_third_party_identifier_callback_mock = Mock(
+            return_value=make_awaitable(None)
+        )
+        on_remove_user_third_party_identifier_callback_mock = Mock(
+            return_value=make_awaitable(None)
+        )
+        third_party_rules._on_threepid_bind_callbacks.append(
+            on_add_user_third_party_identifier_callback_mock
+        )
+        third_party_rules._on_threepid_bind_callbacks.append(
+            on_remove_user_third_party_identifier_callback_mock
+        )
+
+        # Register an admin user.
+        self.register_user("admin", "password", admin=True)
+        admin_tok = self.login("admin", "password")
+
+        # Also register a normal user we can modify.
+        user_id = self.register_user("user", "password")
+
+        # Add a 3PID to the user.
+        channel = self.make_request(
+            "PUT",
+            "/_synapse/admin/v2/users/%s" % user_id,
+            {
+                "threepids": [
+                    {
+                        "medium": "email",
+                        "address": "foo@example.com",
+                    },
+                ],
+            },
+            access_token=admin_tok,
+        )
+
+        # Check that the mocked add callback was called with the appropriate
+        # 3PID details.
+        self.assertEqual(channel.code, 200, channel.json_body)
+        on_add_user_third_party_identifier_callback_mock.assert_called_once()
+        args = on_add_user_third_party_identifier_callback_mock.call_args[0]
+        self.assertEqual(args, (user_id, "email", "foo@example.com"))
+
+        # Now remove the 3PID from the user
+        channel = self.make_request(
+            "PUT",
+            "/_synapse/admin/v2/users/%s" % user_id,
+            {
+                "threepids": [],
+            },
+            access_token=admin_tok,
+        )
+
+        # Check that the mocked remove callback was called with the appropriate
+        # 3PID details.
+        self.assertEqual(channel.code, 200, channel.json_body)
+        on_remove_user_third_party_identifier_callback_mock.assert_called_once()
+        args = on_remove_user_third_party_identifier_callback_mock.call_args[0]
+        self.assertEqual(args, (user_id, "email", "foo@example.com"))
+
+    def test_on_remove_user_third_party_identifier_is_called_on_deactivate(
+        self,
+    ) -> None:
+        """Tests that the on_remove_user_third_party_identifier module callback is called
+        when a user is deactivated and their third-party ID associations are deleted.
+        """
+        # Pretend to be a Synapse module and register both callbacks as mocks.
+        third_party_rules = self.hs.get_third_party_event_rules()
+        on_remove_user_third_party_identifier_callback_mock = Mock(
+            return_value=make_awaitable(None)
+        )
+        third_party_rules._on_threepid_bind_callbacks.append(
+            on_remove_user_third_party_identifier_callback_mock
+        )
+
+        # Register an admin user.
+        self.register_user("admin", "password", admin=True)
+        admin_tok = self.login("admin", "password")
+
+        # Also register a normal user we can modify.
+        user_id = self.register_user("user", "password")
+
+        # Add a 3PID to the user.
+        channel = self.make_request(
+            "PUT",
+            "/_synapse/admin/v2/users/%s" % user_id,
+            {
+                "threepids": [
+                    {
+                        "medium": "email",
+                        "address": "foo@example.com",
+                    },
+                ],
+            },
+            access_token=admin_tok,
+        )
+        self.assertEqual(channel.code, 200, channel.json_body)
+
+        # Now deactivate the user.
+        channel = self.make_request(
+            "PUT",
+            "/_synapse/admin/v2/users/%s" % user_id,
+            {
+                "deactivated": True,
+            },
+            access_token=admin_tok,
+        )
+
+        # Check that the mocked remove callback was called with the appropriate
+        # 3PID details.
+        self.assertEqual(channel.code, 200, channel.json_body)
+        on_remove_user_third_party_identifier_callback_mock.assert_called_once()
+        args = on_remove_user_third_party_identifier_callback_mock.call_args[0]
+        self.assertEqual(args, (user_id, "email", "foo@example.com"))