bugfix: E2EE device keys could sometimes not be sent to remote servers (#2466)

* Fix flakey sytest 'Local device key changes get to remote servers'

* Debug logs

* Remove internal/test and use /test only

Remove a lot of ancient code too.

* Use FederationRoomserverAPI in more places

* Use more interfaces in federationapi; begin adding regression test

* Linting

* Add regression test

* Unbreak tests

* ALL THE LOGS

* Fix a race condition which could cause events to not be sent to servers

If a new room event which rewrites state arrives, we remove all joined hosts
then re-calculate them. This wasn't done in a transaction so for a brief period
we would have no joined hosts. During this interim, key change events which arrive
would not be sent to destination servers. This would sporadically fail on sytest.

* Unbreak new tests

* Linting

1 files changed, 46 insertions, 4 deletions

diff --git a/test/user.go b/test/user.go
index 41a66e1c..0020098a 100644
--- a/test/user.go
+++ b/test/user.go
@@ -15,22 +15,64 @@
 package test
 
 import (
+	"crypto/ed25519"
 	"fmt"
 	"sync/atomic"
+	"testing"
+
+	"github.com/matrix-org/gomatrixserverlib"
 )
 
 var (
 	userIDCounter = int64(0)
+
+	serverName = gomatrixserverlib.ServerName("test")
+	keyID      = gomatrixserverlib.KeyID("ed25519:test")
+	privateKey = ed25519.NewKeyFromSeed([]byte{
+		1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,
+		17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32,
+	})
+
+	// private keys that tests can use
+	PrivateKeyA = ed25519.NewKeyFromSeed([]byte{
+		1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,
+		17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 77,
+	})
+	PrivateKeyB = ed25519.NewKeyFromSeed([]byte{
+		1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,
+		17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 66,
+	})
 )
 
 type User struct {
 	ID string
+	// key ID and private key of the server who has this user, if known.
+	keyID   gomatrixserverlib.KeyID
+	privKey ed25519.PrivateKey
+	srvName gomatrixserverlib.ServerName
+}
+
+type UserOpt func(*User)
+
+func WithSigningServer(srvName gomatrixserverlib.ServerName, keyID gomatrixserverlib.KeyID, privKey ed25519.PrivateKey) UserOpt {
+	return func(u *User) {
+		u.keyID = keyID
+		u.privKey = privKey
+		u.srvName = srvName
+	}
 }
 
-func NewUser() *User {
+func NewUser(t *testing.T, opts ...UserOpt) *User {
 	counter := atomic.AddInt64(&userIDCounter, 1)
-	u := &User{
-		ID: fmt.Sprintf("@%d:localhost", counter),
+	var u User
+	for _, opt := range opts {
+		opt(&u)
+	}
+	if u.keyID == "" || u.srvName == "" || u.privKey == nil {
+		t.Logf("NewUser: missing signing server credentials; using default.")
+		WithSigningServer(serverName, keyID, privateKey)(&u)
 	}
-	return u
+	u.ID = fmt.Sprintf("@%d:%s", counter, u.srvName)
+	t.Logf("NewUser: created user %s", u.ID)
+	return &u
 }