test_appservice.py

        # Define an application service for the tests
        self._service_token = "VERYSECRET"
        self._service = ApplicationService(
            self._service_token,
            "as1",
            "@as.sender:test",
            namespaces={
                "users": [
                    {"regex": "@_as_.*:test", "exclusive": True},
                    {"regex": "@as.sender:test", "exclusive": True},
                ]
            },
            msc3202_transaction_extensions=True,
        )
        self.hs.get_datastores().main.services_cache = [self._service]

        # Register some appservice users
        self._sender_user, self._sender_device = self.register_appservice_user(
            "as.sender", self._service_token
        )
        self._namespaced_user, self._namespaced_device = self.register_appservice_user(
            "_as_user1", self._service_token
        )

        # Register a real user as well.
        self._real_user = self.register_user("real.user", "meow")
        self._real_user_token = self.login("real.user", "meow")

    async def _add_otks_for_device(
        self, user_id: str, device_id: str, otk_count: int
    ) -> None:
        """
        Add some dummy keys. It doesn't matter if they're not a real algorithm;
        that should be opaque to the server anyway.
        """
        await self.hs.get_datastores().main.add_e2e_one_time_keys(
            user_id,
            device_id,
            self.clock.time_msec(),
            [("algo", f"k{i}", "{}") for i in range(otk_count)],
        )

    async def _add_fallback_key_for_device(
        self, user_id: str, device_id: str, used: bool
    ) -> None:
        """
        Adds a fake fallback key to a device, optionally marking it as used
        right away.
        """
        store = self.hs.get_datastores().main
        await store.set_e2e_fallback_keys(user_id, device_id, {"algo:fk": "fall back!"})
        if used is True:
            # Mark the key as used
            await store.db_pool.simple_update_one(
                table="e2e_fallback_keys_json",
                keyvalues={
                    "user_id": user_id,
                    "device_id": device_id,
                    "algorithm": "algo",
                    "key_id": "fk",
                },
                updatevalues={"used": True},
                desc="_get_fallback_key_set_used",
            )

    def _set_up_devices_and_a_room(self) -> str:
        """
        Helper to set up devices for all the users
        and a room for the users to talk in.
        """

        async def preparation():
            await self._add_otks_for_device(self._sender_user, self._sender_device, 42)
            await self._add_fallback_key_for_device(
                self._sender_user, self._sender_device, used=True
            )
            await self._add_otks_for_device(
                self._namespaced_user, self._namespaced_device, 36
            )
            await self._add_fallback_key_for_device(
                self._namespaced_user, self._namespaced_device, used=False
            )

            # Register a device for the real user, too, so that we can later ensure
            # that we don't leak information to the AS about the non-AS user.
            await self.hs.get_datastores().main.store_device(
                self._real_user, "REALDEV", "UltraMatrix 3000"
            )
            await self._add_otks_for_device(self._real_user, "REALDEV", 50)

        self.get_success(preparation())

        room_id = self.helper.create_room_as(
            self._real_user, is_public=True, tok=self._real_user_token
        )
        self.helper.join(
            room_id,
            self._namespaced_user,
            tok=self._service_token,
            appservice_user_id=self._namespaced_user,
        )

        # Check it was called for sanity. (This was to send the join event to the AS.)
        self.send_mock.assert_called()
        self.send_mock.reset_mock()

        return room_id

    @override_config(
        {"experimental_features": {"msc3202_transaction_extensions": True}}
    )
    def test_application_services_receive_otk_counts_and_fallback_key_usages_with_pdus(
        self,
    ) -> None:
        """
        Tests that:
        - the AS receives one-time key counts and unused fallback keys for:
            - the specified sender; and
            - any user who is in receipt of the PDUs
        """

        room_id = self._set_up_devices_and_a_room()

        # Send a message into the AS's room
        self.helper.send(room_id, "woof woof", tok=self._real_user_token)

        # Capture what was sent as an AS transaction.
        self.send_mock.assert_called()
        last_args, _last_kwargs = self.send_mock.call_args
        otks: Optional[TransactionOneTimeKeysCount] = last_args[self.ARG_OTK_COUNTS]
        unused_fallbacks: Optional[TransactionUnusedFallbackKeys] = last_args[
            self.ARG_FALLBACK_KEYS
        ]

        self.assertEqual(
            otks,
            {
                "@as.sender:test": {self._sender_device: {"algo": 42}},
                "@_as_user1:test": {self._namespaced_device: {"algo": 36}},
            },
        )
        self.assertEqual(
            unused_fallbacks,
            {
                "@as.sender:test": {self._sender_device: []},
                "@_as_user1:test": {self._namespaced_device: ["algo"]},
            },
        )