diff --git a/spec/unit/crypto/algorithms/megolm.spec.js b/spec/unit/crypto/algorithms/megolm.spec.js
index dd846403f..22888d1a3 100644
--- a/spec/unit/crypto/algorithms/megolm.spec.js
+++ b/spec/unit/crypto/algorithms/megolm.spec.js
@@ -321,6 +321,13 @@ describe("MegolmDecryption", function() {
                         rotation_period_ms: 9999999999999,
                     },
                 });
+
+                // Splice the real method onto the mock object as megolm uses this method
+                // on the crypto class in order to encrypt / start sessions
+                mockCrypto.encryptAndSendToDevices = Crypto.prototype.encryptAndSendToDevices;
+                mockCrypto.olmDevice = olmDevice;
+                mockCrypto.baseApis = mockBaseApis;
+
                 mockRoom = {
                     getEncryptionTargetMembers: jest.fn().mockReturnValue(
                         [{ userId: "@alice:home.server" }],
diff --git a/spec/unit/webrtc/call.spec.ts b/spec/unit/webrtc/call.spec.ts
index 7308bb262..fe7fa72ba 100644
--- a/spec/unit/webrtc/call.spec.ts
+++ b/spec/unit/webrtc/call.spec.ts
@@ -471,6 +471,7 @@ describe('Call', function() {
                     },
                 };
             },
+            getSender: () => "@test:foo",
         });
 
         await call.updateLocalUsermediaStream(
@@ -510,6 +511,7 @@ describe('Call', function() {
                     [SDPStreamMetadataKey]: {},
                 };
             },
+            getSender: () => "@test:foo",
         });
 
         await call.upgradeCall(false, true);