[pseudoIDs] More pseudo ID fixes - Part 2 (#3181)

Fixes include:
- Translating state keys that contain user IDs to their respective room
keys for both querying and sending state events
- **NOTE**: there may be design discussion needed on what should happen
when sender keys cannot be found for users
- A simple fix for kicking guests from rooms properly
- Logic for boundary history visibilities was slightly off (I'm
surprised this only manifested in pseudo ID room versions)

Signed-off-by: `Sam Wedgwood <sam@wedgwood.dev>`

4 files changed, 584 insertions, 0 deletions

diff --git a/clientapi/routing/sendevent.go b/clientapi/routing/sendevent.go
index a167a5a7..f81e9c1e 100644
--- a/clientapi/routing/sendevent.go
+++ b/clientapi/routing/sendevent.go
@@ -29,6 +29,7 @@ import (
 	"github.com/matrix-org/dendrite/roomserver/api"
 	"github.com/matrix-org/dendrite/roomserver/types"
 	"github.com/matrix-org/dendrite/setup/config"
+	"github.com/matrix-org/dendrite/syncapi/synctypes"
 	userapi "github.com/matrix-org/dendrite/userapi/api"
 	"github.com/matrix-org/gomatrixserverlib"
 	"github.com/matrix-org/gomatrixserverlib/spec"
@@ -92,6 +93,30 @@ func SendEvent(
 		}
 	}
 
+	// Translate user ID state keys to room keys in pseudo ID rooms
+	if roomVersion == gomatrixserverlib.RoomVersionPseudoIDs && stateKey != nil {
+		parsedRoomID, innerErr := spec.NewRoomID(roomID)
+		if innerErr != nil {
+			return util.JSONResponse{
+				Code: http.StatusBadRequest,
+				JSON: spec.InvalidParam("invalid room ID"),
+			}
+		}
+
+		newStateKey, innerErr := synctypes.FromClientStateKey(*parsedRoomID, *stateKey, func(roomID spec.RoomID, userID spec.UserID) (*spec.SenderID, error) {
+			return rsAPI.QuerySenderIDForUser(req.Context(), roomID, userID)
+		})
+		if innerErr != nil {
+			// TODO: work out better logic for failure cases (e.g. sender ID not found)
+			util.GetLogger(req.Context()).WithError(innerErr).Error("synctypes.FromClientStateKey failed")
+			return util.JSONResponse{
+				Code: http.StatusInternalServerError,
+				JSON: spec.Unknown("internal server error"),
+			}
+		}
+		stateKey = newStateKey
+	}
+
 	// create a mutex for the specific user in the specific room
 	// this avoids a situation where events that are received in quick succession are sent to the roomserver in a jumbled order
 	userID := device.UserID
diff --git a/clientapi/routing/sendevent_test.go b/clientapi/routing/sendevent_test.go
new file mode 100644
index 00000000..9cdd7535
--- /dev/null
+++ b/clientapi/routing/sendevent_test.go
@@ -0,0 +1,275 @@
+package routing
+
+import (
+	"context"
+	"crypto/ed25519"
+	"fmt"
+	"io"
+	"net/http"
+	"strings"
+	"testing"
+
+	rsapi "github.com/matrix-org/dendrite/roomserver/api"
+	"github.com/matrix-org/dendrite/roomserver/types"
+	"github.com/matrix-org/dendrite/setup/config"
+	uapi "github.com/matrix-org/dendrite/userapi/api"
+	"github.com/matrix-org/gomatrixserverlib"
+	"github.com/matrix-org/gomatrixserverlib/fclient"
+	"github.com/matrix-org/gomatrixserverlib/spec"
+	"gotest.tools/v3/assert"
+)
+
+// Mock roomserver API for testing
+//
+// Currently pretty specialised for the pseudo ID test, so will need
+// editing if future (other) sendevent tests are using this.
+type sendEventTestRoomserverAPI struct {
+	rsapi.ClientRoomserverAPI
+	t           *testing.T
+	roomIDStr   string
+	roomVersion gomatrixserverlib.RoomVersion
+	roomState   []*types.HeaderedEvent
+
+	// userID -> room key
+	senderMapping map[string]ed25519.PrivateKey
+
+	savedInputRoomEvents []rsapi.InputRoomEvent
+}
+
+func (s *sendEventTestRoomserverAPI) QueryRoomVersionForRoom(ctx context.Context, roomID string) (gomatrixserverlib.RoomVersion, error) {
+	if roomID == s.roomIDStr {
+		return s.roomVersion, nil
+	} else {
+		s.t.Logf("room version queried for %s", roomID)
+		return "", fmt.Errorf("unknown room")
+	}
+}
+
+func (s *sendEventTestRoomserverAPI) QueryCurrentState(ctx context.Context, req *rsapi.QueryCurrentStateRequest, res *rsapi.QueryCurrentStateResponse) error {
+	res.StateEvents = map[gomatrixserverlib.StateKeyTuple]*types.HeaderedEvent{}
+	for _, stateKeyTuple := range req.StateTuples {
+		for _, stateEv := range s.roomState {
+			if stateEv.Type() == stateKeyTuple.EventType && stateEv.StateKey() != nil && *stateEv.StateKey() == stateKeyTuple.StateKey {
+				res.StateEvents[stateKeyTuple] = stateEv
+			}
+		}
+	}
+	return nil
+}
+
+func (s *sendEventTestRoomserverAPI) QueryLatestEventsAndState(ctx context.Context, req *rsapi.QueryLatestEventsAndStateRequest, res *rsapi.QueryLatestEventsAndStateResponse) error {
+	if req.RoomID == s.roomIDStr {
+		res.RoomExists = true
+		res.RoomVersion = s.roomVersion
+
+		res.StateEvents = make([]*types.HeaderedEvent, len(s.roomState))
+		copy(res.StateEvents, s.roomState)
+
+		res.LatestEvents = []string{}
+		res.Depth = 1
+		return nil
+	} else {
+		s.t.Logf("room event/state queried for %s", req.RoomID)
+		return fmt.Errorf("unknown room")
+	}
+
+}
+
+func (s *sendEventTestRoomserverAPI) QuerySenderIDForUser(
+	ctx context.Context,
+	roomID spec.RoomID,
+	userID spec.UserID,
+) (*spec.SenderID, error) {
+	if roomID.String() == s.roomIDStr {
+		if s.roomVersion == gomatrixserverlib.RoomVersionPseudoIDs {
+			roomKey, ok := s.senderMapping[userID.String()]
+			if ok {
+				sender := spec.SenderIDFromPseudoIDKey(roomKey)
+				return &sender, nil
+			} else {
+				return nil, nil
+			}
+		} else {
+			senderID := spec.SenderIDFromUserID(userID)
+			return &senderID, nil
+		}
+	}
+
+	return nil, fmt.Errorf("room not found")
+}
+
+func (s *sendEventTestRoomserverAPI) QueryUserIDForSender(
+	ctx context.Context,
+	roomID spec.RoomID,
+	senderID spec.SenderID,
+) (*spec.UserID, error) {
+	if roomID.String() == s.roomIDStr {
+		if s.roomVersion == gomatrixserverlib.RoomVersionPseudoIDs {
+			for uID, roomKey := range s.senderMapping {
+				if string(spec.SenderIDFromPseudoIDKey(roomKey)) == string(senderID) {
+					parsedUserID, err := spec.NewUserID(uID, true)
+					if err != nil {
+						s.t.Fatalf("Mock QueryUserIDForSender failed: %s", err)
+					}
+					return parsedUserID, nil
+				}
+			}
+		} else {
+			userID := senderID.ToUserID()
+			if userID == nil {
+				return nil, fmt.Errorf("bad sender ID")
+			}
+			return userID, nil
+		}
+	}
+
+	return nil, fmt.Errorf("room not found")
+}
+
+func (s *sendEventTestRoomserverAPI) SigningIdentityFor(ctx context.Context, roomID spec.RoomID, sender spec.UserID) (fclient.SigningIdentity, error) {
+	if s.roomIDStr == roomID.String() {
+		if s.roomVersion == gomatrixserverlib.RoomVersionPseudoIDs {
+			roomKey, ok := s.senderMapping[sender.String()]
+			if !ok {
+				s.t.Logf("SigningIdentityFor used with unknown user ID: %v", sender.String())
+				return fclient.SigningIdentity{}, fmt.Errorf("could not get signing identity for %v", sender.String())
+			}
+			return fclient.SigningIdentity{PrivateKey: roomKey}, nil
+		} else {
+			return fclient.SigningIdentity{PrivateKey: ed25519.NewKeyFromSeed(make([]byte, 32))}, nil
+		}
+	}
+
+	return fclient.SigningIdentity{}, fmt.Errorf("room not found")
+}
+
+func (s *sendEventTestRoomserverAPI) InputRoomEvents(ctx context.Context, req *rsapi.InputRoomEventsRequest, res *rsapi.InputRoomEventsResponse) {
+	s.savedInputRoomEvents = req.InputRoomEvents
+}
+
+// Test that user ID state keys are translated correctly
+func Test_SendEvent_PseudoIDStateKeys(t *testing.T) {
+	nonpseudoIDRoomVersion := gomatrixserverlib.RoomVersionV10
+	pseudoIDRoomVersion := gomatrixserverlib.RoomVersionPseudoIDs
+
+	senderKeySeed := make([]byte, 32)
+	senderUserID := "@testuser:domain"
+	senderPrivKey := ed25519.NewKeyFromSeed(senderKeySeed)
+	senderPseudoID := string(spec.SenderIDFromPseudoIDKey(senderPrivKey))
+
+	eventType := "com.example.test"
+	roomIDStr := "!id:domain"
+
+	device := &uapi.Device{
+		UserID: senderUserID,
+	}
+
+	t.Run("user ID state key are not translated to room key in non-pseudo ID room", func(t *testing.T) {
+		eventsJSON := []string{
+			fmt.Sprintf(`{"type":"m.room.create","state_key":"","room_id":"%v","sender":"%v","content":{"creator":"%v","room_version":"%v"}}`, roomIDStr, senderUserID, senderUserID, nonpseudoIDRoomVersion),
+			fmt.Sprintf(`{"type":"m.room.member","state_key":"%v","room_id":"%v","sender":"%v","content":{"membership":"join"}}`, senderUserID, roomIDStr, senderUserID),
+		}
+
+		roomState, err := createEvents(eventsJSON, nonpseudoIDRoomVersion)
+		if err != nil {
+			t.Fatalf("failed to prepare state events: %s", err.Error())
+		}
+
+		rsAPI := &sendEventTestRoomserverAPI{
+			t:           t,
+			roomIDStr:   roomIDStr,
+			roomVersion: nonpseudoIDRoomVersion,
+			roomState:   roomState,
+		}
+
+		req, err := http.NewRequest("POST", "https://domain", io.NopCloser(strings.NewReader("{}")))
+		if err != nil {
+			t.Fatalf("failed to make new request: %s", err.Error())
+		}
+
+		cfg := &config.ClientAPI{}
+
+		resp := SendEvent(req, device, roomIDStr, eventType, nil, &senderUserID, cfg, rsAPI, nil)
+
+		if resp.Code != http.StatusOK {
+			t.Fatalf("non-200 HTTP code returned: %v\nfull response: %v", resp.Code, resp)
+		}
+
+		assert.Equal(t, len(rsAPI.savedInputRoomEvents), 1)
+
+		ev := rsAPI.savedInputRoomEvents[0]
+		stateKey := ev.Event.StateKey()
+		if stateKey == nil {
+			t.Fatalf("submitted InputRoomEvent has nil state key, when it should be %v", senderUserID)
+		}
+		if *stateKey != senderUserID {
+			t.Fatalf("expected submitted InputRoomEvent to have user ID state key\nfound: %v\nexpected: %v", *stateKey, senderUserID)
+		}
+	})
+
+	t.Run("user ID state key are translated to room key in pseudo ID room", func(t *testing.T) {
+		eventsJSON := []string{
+			fmt.Sprintf(`{"type":"m.room.create","state_key":"","room_id":"%v","sender":"%v","content":{"creator":"%v","room_version":"%v"}}`, roomIDStr, senderPseudoID, senderPseudoID, pseudoIDRoomVersion),
+			fmt.Sprintf(`{"type":"m.room.member","state_key":"%v","room_id":"%v","sender":"%v","content":{"membership":"join"}}`, senderPseudoID, roomIDStr, senderPseudoID),
+		}
+
+		roomState, err := createEvents(eventsJSON, pseudoIDRoomVersion)
+		if err != nil {
+			t.Fatalf("failed to prepare state events: %s", err.Error())
+		}
+
+		rsAPI := &sendEventTestRoomserverAPI{
+			t:           t,
+			roomIDStr:   roomIDStr,
+			roomVersion: pseudoIDRoomVersion,
+			senderMapping: map[string]ed25519.PrivateKey{
+				senderUserID: senderPrivKey,
+			},
+			roomState: roomState,
+		}
+
+		req, err := http.NewRequest("POST", "https://domain", io.NopCloser(strings.NewReader("{}")))
+		if err != nil {
+			t.Fatalf("failed to make new request: %s", err.Error())
+		}
+
+		cfg := &config.ClientAPI{}
+
+		resp := SendEvent(req, device, roomIDStr, eventType, nil, &senderUserID, cfg, rsAPI, nil)
+
+		if resp.Code != http.StatusOK {
+			t.Fatalf("non-200 HTTP code returned: %v\nfull response: %v", resp.Code, resp)
+		}
+
+		assert.Equal(t, len(rsAPI.savedInputRoomEvents), 1)
+
+		ev := rsAPI.savedInputRoomEvents[0]
+		stateKey := ev.Event.StateKey()
+		if stateKey == nil {
+			t.Fatalf("submitted InputRoomEvent has nil state key, when it should be %v", senderPseudoID)
+		}
+		if *stateKey != senderPseudoID {
+			t.Fatalf("expected submitted InputRoomEvent to have pseudo ID state key\nfound: %v\nexpected: %v", *stateKey, senderPseudoID)
+		}
+	})
+}
+
+func createEvents(eventsJSON []string, roomVer gomatrixserverlib.RoomVersion) ([]*types.HeaderedEvent, error) {
+	events := make([]*types.HeaderedEvent, len(eventsJSON))
+
+	roomVerImpl, err := gomatrixserverlib.GetRoomVersion(roomVer)
+	if err != nil {
+		return nil, fmt.Errorf("no roomver impl: %s", err.Error())
+	}
+
+	for i, eventJSON := range eventsJSON {
+		pdu, evErr := roomVerImpl.NewEventFromTrustedJSON([]byte(eventJSON), false)
+		if evErr != nil {
+			return nil, fmt.Errorf("failed to make event: %s", err.Error())
+		}
+		ev := types.HeaderedEvent{PDU: pdu}
+		events[i] = &ev
+	}
+
+	return events, nil
+}
diff --git a/clientapi/routing/state.go b/clientapi/routing/state.go
index f53cb301..7648dc47 100644
--- a/clientapi/routing/state.go
+++ b/clientapi/routing/state.go
@@ -217,6 +217,37 @@ func OnIncomingStateTypeRequest(
 	var worldReadable bool
 	var wantLatestState bool
 
+	roomVer, err := rsAPI.QueryRoomVersionForRoom(ctx, roomID)
+	if err != nil {
+		return util.JSONResponse{
+			Code: http.StatusForbidden,
+			JSON: spec.Forbidden(fmt.Sprintf("Unknown room %q or user %q has never joined this room", roomID, device.UserID)),
+		}
+	}
+
+	// Translate user ID state keys to room keys in pseudo ID rooms
+	if roomVer == gomatrixserverlib.RoomVersionPseudoIDs {
+		parsedRoomID, err := spec.NewRoomID(roomID)
+		if err != nil {
+			return util.JSONResponse{
+				Code: http.StatusNotFound,
+				JSON: spec.InvalidParam("invalid room ID"),
+			}
+		}
+		newStateKey, err := synctypes.FromClientStateKey(*parsedRoomID, stateKey, func(roomID spec.RoomID, userID spec.UserID) (*spec.SenderID, error) {
+			return rsAPI.QuerySenderIDForUser(ctx, roomID, userID)
+		})
+		if err != nil {
+			// TODO: work out better logic for failure cases (e.g. sender ID not found)
+			util.GetLogger(ctx).WithError(err).Error("synctypes.FromClientStateKey failed")
+			return util.JSONResponse{
+				Code: http.StatusInternalServerError,
+				JSON: spec.Unknown("internal server error"),
+			}
+		}
+		stateKey = *newStateKey
+	}
+
 	// Always fetch visibility so that we can work out whether to show
 	// the latest events or the last event from when the user was joined.
 	// Then include the requested event type and state key, assuming it
diff --git a/clientapi/routing/state_test.go b/clientapi/routing/state_test.go
new file mode 100644
index 00000000..93b04372
--- /dev/null
+++ b/clientapi/routing/state_test.go
@@ -0,0 +1,253 @@
+package routing
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"testing"
+
+	rsapi "github.com/matrix-org/dendrite/roomserver/api"
+	"github.com/matrix-org/dendrite/roomserver/types"
+	"github.com/matrix-org/dendrite/setup/config"
+	uapi "github.com/matrix-org/dendrite/userapi/api"
+	"github.com/matrix-org/gomatrixserverlib"
+	"github.com/matrix-org/gomatrixserverlib/spec"
+	"github.com/matrix-org/util"
+	"gotest.tools/v3/assert"
+)
+
+var ()
+
+type stateTestRoomserverAPI struct {
+	rsapi.RoomserverInternalAPI
+	t           *testing.T
+	roomState   map[gomatrixserverlib.StateKeyTuple]*types.HeaderedEvent
+	roomIDStr   string
+	roomVersion gomatrixserverlib.RoomVersion
+	userIDStr   string
+	// userID -> senderID
+	senderMapping map[string]string
+}
+
+func (s stateTestRoomserverAPI) QueryRoomVersionForRoom(ctx context.Context, roomID string) (gomatrixserverlib.RoomVersion, error) {
+	if roomID == s.roomIDStr {
+		return s.roomVersion, nil
+	} else {
+		s.t.Logf("room version queried for %s", roomID)
+		return "", fmt.Errorf("unknown room")
+	}
+}
+
+func (s stateTestRoomserverAPI) QueryLatestEventsAndState(
+	ctx context.Context,
+	req *rsapi.QueryLatestEventsAndStateRequest,
+	res *rsapi.QueryLatestEventsAndStateResponse,
+) error {
+	res.RoomExists = req.RoomID == s.roomIDStr
+	if !res.RoomExists {
+		return nil
+	}
+
+	res.StateEvents = []*types.HeaderedEvent{}
+	for _, stateKeyTuple := range req.StateToFetch {
+		val, ok := s.roomState[stateKeyTuple]
+		if ok && val != nil {
+			res.StateEvents = append(res.StateEvents, val)
+		}
+	}
+
+	return nil
+}
+
+func (s stateTestRoomserverAPI) QueryMembershipForUser(
+	ctx context.Context,
+	req *rsapi.QueryMembershipForUserRequest,
+	res *rsapi.QueryMembershipForUserResponse,
+) error {
+	if req.UserID.String() == s.userIDStr {
+		res.HasBeenInRoom = true
+		res.IsInRoom = true
+		res.RoomExists = true
+		res.Membership = spec.Join
+	}
+
+	return nil
+}
+
+func (s stateTestRoomserverAPI) QuerySenderIDForUser(
+	ctx context.Context,
+	roomID spec.RoomID,
+	userID spec.UserID,
+) (*spec.SenderID, error) {
+	sID, ok := s.senderMapping[userID.String()]
+	if ok {
+		sender := spec.SenderID(sID)
+		return &sender, nil
+	} else {
+		return nil, nil
+	}
+}
+
+func (s stateTestRoomserverAPI) QueryUserIDForSender(
+	ctx context.Context,
+	roomID spec.RoomID,
+	senderID spec.SenderID,
+) (*spec.UserID, error) {
+	for uID, sID := range s.senderMapping {
+		if sID == string(senderID) {
+			parsedUserID, err := spec.NewUserID(uID, true)
+			if err != nil {
+				s.t.Fatalf("Mock QueryUserIDForSender failed: %s", err)
+			}
+			return parsedUserID, nil
+		}
+	}
+	return nil, nil
+}
+
+func (s stateTestRoomserverAPI) QueryStateAfterEvents(
+	ctx context.Context,
+	req *rsapi.QueryStateAfterEventsRequest,
+	res *rsapi.QueryStateAfterEventsResponse,
+) error {
+	return nil
+}
+
+func Test_OnIncomingStateTypeRequest(t *testing.T) {
+	var tempRoomServerCfg config.RoomServer
+	tempRoomServerCfg.Defaults(config.DefaultOpts{})
+	defaultRoomVersion := tempRoomServerCfg.DefaultRoomVersion
+	pseudoIDRoomVersion := gomatrixserverlib.RoomVersionPseudoIDs
+	nonPseudoIDRoomVersion := gomatrixserverlib.RoomVersionV10
+
+	userIDStr := "@testuser:domain"
+	eventType := "com.example.test"
+	stateKey := "testStateKey"
+	roomIDStr := "!id:domain"
+
+	device := &uapi.Device{
+		UserID: userIDStr,
+	}
+
+	t.Run("request simple state key", func(t *testing.T) {
+		ctx := context.Background()
+
+		rsAPI := stateTestRoomserverAPI{
+			roomVersion: defaultRoomVersion,
+			roomIDStr:   roomIDStr,
+			roomState: map[gomatrixserverlib.StateKeyTuple]*types.HeaderedEvent{
+				{
+					EventType: eventType,
+					StateKey:  stateKey,
+				}: mustCreateStatePDU(t, defaultRoomVersion, roomIDStr, eventType, stateKey, map[string]interface{}{
+					"foo": "bar",
+				}),
+			},
+			userIDStr: userIDStr,
+		}
+
+		jsonResp := OnIncomingStateTypeRequest(ctx, device, rsAPI, roomIDStr, eventType, stateKey, false)
+
+		assert.DeepEqual(t, jsonResp, util.JSONResponse{
+			Code: http.StatusOK,
+			JSON: spec.RawJSON(`{"foo":"bar"}`),
+		})
+	})
+
+	t.Run("user ID key translated to room key in pseudo ID rooms", func(t *testing.T) {
+		ctx := context.Background()
+
+		stateSenderUserID := "@sender:domain"
+		stateSenderRoomKey := "testsenderkey"
+
+		rsAPI := stateTestRoomserverAPI{
+			roomVersion: pseudoIDRoomVersion,
+			roomIDStr:   roomIDStr,
+			roomState: map[gomatrixserverlib.StateKeyTuple]*types.HeaderedEvent{
+				{
+					EventType: eventType,
+					StateKey:  stateSenderRoomKey,
+				}: mustCreateStatePDU(t, pseudoIDRoomVersion, roomIDStr, eventType, stateSenderRoomKey, map[string]interface{}{
+					"foo": "bar",
+				}),
+				{
+					EventType: eventType,
+					StateKey:  stateSenderUserID,
+				}: mustCreateStatePDU(t, pseudoIDRoomVersion, roomIDStr, eventType, stateSenderUserID, map[string]interface{}{
+					"not": "thisone",
+				}),
+			},
+			userIDStr: userIDStr,
+			senderMapping: map[string]string{
+				stateSenderUserID: stateSenderRoomKey,
+			},
+		}
+
+		jsonResp := OnIncomingStateTypeRequest(ctx, device, rsAPI, roomIDStr, eventType, stateSenderUserID, false)
+
+		assert.DeepEqual(t, jsonResp, util.JSONResponse{
+			Code: http.StatusOK,
+			JSON: spec.RawJSON(`{"foo":"bar"}`),
+		})
+	})
+
+	t.Run("user ID key not translated to room key in non-pseudo ID rooms", func(t *testing.T) {
+		ctx := context.Background()
+
+		stateSenderUserID := "@sender:domain"
+		stateSenderRoomKey := "testsenderkey"
+
+		rsAPI := stateTestRoomserverAPI{
+			roomVersion: nonPseudoIDRoomVersion,
+			roomIDStr:   roomIDStr,
+			roomState: map[gomatrixserverlib.StateKeyTuple]*types.HeaderedEvent{
+				{
+					EventType: eventType,
+					StateKey:  stateSenderRoomKey,
+				}: mustCreateStatePDU(t, nonPseudoIDRoomVersion, roomIDStr, eventType, stateSenderRoomKey, map[string]interface{}{
+					"not": "thisone",
+				}),
+				{
+					EventType: eventType,
+					StateKey:  stateSenderUserID,
+				}: mustCreateStatePDU(t, nonPseudoIDRoomVersion, roomIDStr, eventType, stateSenderUserID, map[string]interface{}{
+					"foo": "bar",
+				}),
+			},
+			userIDStr: userIDStr,
+			senderMapping: map[string]string{
+				stateSenderUserID: stateSenderUserID,
+			},
+		}
+
+		jsonResp := OnIncomingStateTypeRequest(ctx, device, rsAPI, roomIDStr, eventType, stateSenderUserID, false)
+
+		assert.DeepEqual(t, jsonResp, util.JSONResponse{
+			Code: http.StatusOK,
+			JSON: spec.RawJSON(`{"foo":"bar"}`),
+		})
+	})
+}
+
+func mustCreateStatePDU(t *testing.T, roomVer gomatrixserverlib.RoomVersion, roomID string, stateType string, stateKey string, stateContent map[string]interface{}) *types.HeaderedEvent {
+	t.Helper()
+	roomVerImpl := gomatrixserverlib.MustGetRoomVersion(roomVer)
+
+	evBytes, err := json.Marshal(map[string]interface{}{
+		"room_id":   roomID,
+		"type":      stateType,
+		"state_key": stateKey,
+		"content":   stateContent,
+	})
+	if err != nil {
+		t.Fatalf("failed to create event: %v", err)
+	}
+
+	ev, err := roomVerImpl.NewEventFromTrustedJSON(evBytes, false)
+	if err != nil {
+		t.Fatalf("failed to create event: %v", err)
+	}
+
+	return &types.HeaderedEvent{PDU: ev}
+}