Improvements to megolm integration tests (#3060)

The megolm tests were making a few assumptions which they really shouldn't; in
particular:

 * They were creating mock events with event_ids not starting `$`, and lacking
   `sender`, `origin_server_ts` and `unsigned` properties

 * They were not including the (now) required `keys.ed25519` property inside
   the ciphertext of an olm message.

These work ok currently, but they aren't really correct, and they cause
problems when testing the new rust implementation.

spec/integ/megolm-integ.spec.ts

@@ -1,6 +1,6 @@
 /*
 Copyright 2016 OpenMarket Ltd
-Copyright 2019-2022 The Matrix.org Foundation C.I.C.
+Copyright 2019-2023 The Matrix.org Foundation C.I.C.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -59,13 +59,21 @@ interface ToDeviceEvent {
     type: string;
 }
 
-// encrypt an event with olm
+/** encrypt an event with an existing olm session */
 function encryptOlmEvent(opts: {
+    /** the sender's user id */
     sender?: string;
+    /** the sender's curve25519 key */
     senderKey: string;
+    /** the sender's ed25519 key */
+    senderSigningKey: string;
+    /** the olm session to use for encryption */
     p2pSession: Olm.Session;
+    /** the recipient client */
     recipient: TestClient;
+    /** the payload of the message */
     plaincontent?: object;
+    /** the event type of the payload */
     plaintype?: string;
 }): ToDeviceEvent {
     expect(opts.senderKey).toBeTruthy();
@@ -78,6 +86,9 @@ function encryptOlmEvent(opts: {
         recipient_keys: {
             ed25519: opts.recipient.getSigningKey(),
         },
+        keys: {
+            ed25519: opts.senderSigningKey,
+        },
         sender: opts.sender || "@bob:xyz",
         type: opts.plaintype || "m.test",
     };
@@ -101,7 +112,7 @@ function encryptMegolmEvent(opts: {
     groupSession: Olm.OutboundGroupSession;
     plaintext?: Partial<IEvent>;
     room_id?: string;
-}): Pick<IEvent, "event_id" | "content" | "type"> {
+}): IEvent {
     expect(opts.senderKey).toBeTruthy();
     expect(opts.groupSession).toBeTruthy();
 
@@ -119,30 +130,44 @@ function encryptMegolmEvent(opts: {
         expect(opts.room_id).toBeTruthy();
         plaintext.room_id = opts.room_id;
     }
+    return encryptMegolmEventRawPlainText({ senderKey: opts.senderKey, groupSession: opts.groupSession, plaintext });
+}
 
+function encryptMegolmEventRawPlainText(opts: {
+    senderKey: string;
+    groupSession: Olm.OutboundGroupSession;
+    plaintext: Partial<IEvent>;
+}): IEvent {
     return {
-        event_id: "test_megolm_event_" + Math.random(),
+        event_id: "$test_megolm_event_" + Math.random(),
+        sender: "@not_the_real_sender:example.com",
+        origin_server_ts: 1672944778000,
         content: {
             algorithm: "m.megolm.v1.aes-sha2",
-            ciphertext: opts.groupSession.encrypt(JSON.stringify(plaintext)),
+            ciphertext: opts.groupSession.encrypt(JSON.stringify(opts.plaintext)),
             device_id: "testDevice",
             sender_key: opts.senderKey,
             session_id: opts.groupSession.session_id(),
         },
         type: "m.room.encrypted",
+        unsigned: {},
     };
 }
 
-// build an encrypted room_key event to share a group session
+/** build an encrypted room_key event to share a group session, using an existing olm session */
 function encryptGroupSessionKey(opts: {
-    senderKey: string;
     recipient: TestClient;
+    /** sender's olm account */
+    olmAccount: Olm.Account;
+    /** sender's olm session with the recipient */
     p2pSession: Olm.Session;
     groupSession: Olm.OutboundGroupSession;
     room_id?: string;
 }): Partial<IEvent> {
+    const senderKeys = JSON.parse(opts.olmAccount.identity_keys());
     return encryptOlmEvent({
-        senderKey: opts.senderKey,
+        senderKey: senderKeys.curve25519,
+        senderSigningKey: senderKeys.ed25519,
         recipient: opts.recipient,
         p2pSession: opts.p2pSession,
         plaincontent: {
@@ -219,6 +244,7 @@ async function establishOlmSession(testClient: TestClient, peerOlmAccount: Olm.A
     const p2pSession = await createOlmSession(peerOlmAccount, testClient);
     const olmEvent = encryptOlmEvent({
         senderKey: peerE2EKeys.curve25519,
+        senderSigningKey: peerE2EKeys.ed25519,
         recipient: testClient,
         p2pSession: p2pSession,
     });
@@ -392,7 +418,9 @@ describe("megolm", () => {
         testSenderKey = testE2eKeys.curve25519;
     });
 
-    afterEach(() => aliceTestClient.stop());
+    afterEach(async () => {
+        await aliceTestClient.stop();
+    });
 
     it("Alice receives a megolm message", async () => {
         await aliceTestClient.start();
@@ -405,8 +433,8 @@ describe("megolm", () => {
 
         // make the room_key event
         const roomKeyEncrypted = encryptGroupSessionKey({
-            senderKey: testSenderKey,
             recipient: aliceTestClient,
+            olmAccount: testOlmAccount,
             p2pSession: p2pSession,
             groupSession: groupSession,
             room_id: ROOM_ID,
@@ -456,8 +484,8 @@ describe("megolm", () => {
 
         // make the room_key event, but don't send it yet
         const roomKeyEncrypted = encryptGroupSessionKey({
-            senderKey: testSenderKey,
             recipient: aliceTestClient,
+            olmAccount: testOlmAccount,
             p2pSession: p2pSession,
             groupSession: groupSession,
             room_id: ROOM_ID,
@@ -516,8 +544,8 @@ describe("megolm", () => {
 
         // make the room_key event
         const roomKeyEncrypted1 = encryptGroupSessionKey({
-            senderKey: testSenderKey,
             recipient: aliceTestClient,
+            olmAccount: testOlmAccount,
             p2pSession: p2pSession,
             groupSession: groupSession,
             room_id: ROOM_ID,
@@ -533,8 +561,8 @@ describe("megolm", () => {
         // make a second room_key event now that we have advanced the group
         // session.
         const roomKeyEncrypted2 = encryptGroupSessionKey({
-            senderKey: testSenderKey,
             recipient: aliceTestClient,
+            olmAccount: testOlmAccount,
             p2pSession: p2pSession,
             groupSession: groupSession,
             room_id: ROOM_ID,
@@ -958,8 +986,8 @@ describe("megolm", () => {
 
         // make the room_key event
         const roomKeyEncrypted = encryptGroupSessionKey({
-            senderKey: testSenderKey,
             recipient: aliceTestClient,
+            olmAccount: testOlmAccount,
             p2pSession: p2pSession,
             groupSession: groupSession,
             room_id: ROOM_ID,
@@ -1088,8 +1116,8 @@ describe("megolm", () => {
 
         // make the room_key event
         const roomKeyEncrypted = encryptGroupSessionKey({
-            senderKey: testSenderKey,
             recipient: aliceTestClient,
+            olmAccount: testOlmAccount,
             p2pSession: p2pSession,
             groupSession: groupSession,
             room_id: ROOM_ID,
@@ -1101,17 +1129,11 @@ describe("megolm", () => {
             room_id: ROOM_ID,
         };
 
-        const messageEncrypted = {
+        const messageEncrypted = encryptMegolmEventRawPlainText({
-            event_id: "test_megolm_event",
+            senderKey: testSenderKey,
-            content: {
+            groupSession: groupSession,
-                algorithm: "m.megolm.v1.aes-sha2",
+            plaintext: plaintext,
-                ciphertext: groupSession.encrypt(JSON.stringify(plaintext)),
+        });
-                device_id: "testDevice",
-                sender_key: testSenderKey,
-                session_id: groupSession.session_id(),
-            },
-            type: "m.room.encrypted",
-        };
 
         // Alice gets both the events in a single sync
         const syncResponse = {
@@ -1149,8 +1171,8 @@ describe("megolm", () => {
 
         // make the room_key event
         const roomKeyEncrypted = encryptGroupSessionKey({
-            senderKey: testSenderKey,
             recipient: aliceTestClient,
+            olmAccount: testOlmAccount,
             p2pSession: p2pSession,
             groupSession: groupSession,
             room_id: ROOM_ID,
@@ -1268,6 +1290,7 @@ describe("megolm", () => {
         );
         const encryptedForwardedKey = encryptOlmEvent({
             sender: "@becca:localhost",
+            senderSigningKey: beccaTestClient.getSigningKey(),
             senderKey: beccaTestClient.getDeviceKey(),
             recipient: aliceTestClient,
             p2pSession: p2pSession,
@@ -1413,6 +1436,7 @@ describe("megolm", () => {
         const encryptedForwardedKey = encryptOlmEvent({
             sender: "@becca:localhost",
             senderKey: beccaTestClient.getDeviceKey(),
+            senderSigningKey: beccaTestClient.getSigningKey(),
             recipient: aliceTestClient,
             p2pSession: p2pSession,
             plaincontent: {