crypto-js: wait for device updates in getUserDevices (#1790)

Wait for up to a second for any in-flight device list updates to complete.

bindings/matrix-sdk-crypto-js/CHANGELOG.md

@@ -1,3 +1,8 @@
+# v0.1.0-alpha.7
+
+-   In `OlmMachine.getUserDevices`, wait a limited time for any in-flight
+    device-list updates to complete.
+
 # v0.1.0-alpha.6
 
 -   Add new accessor `InboundGroupSession.senderKey`.

bindings/matrix-sdk-crypto-js/src/machine.rs

@@ -1,6 +1,6 @@
 //! The crypto specific Olm objects.
 
-use std::{collections::BTreeMap, ops::Deref};
+use std::{collections::BTreeMap, ops::Deref, time::Duration};
 
 use futures_util::StreamExt;
 use js_sys::{Array, Function, Map, Promise, Set};
@@ -582,7 +582,10 @@ impl OlmMachine {
         let me = self.inner.clone();
 
         future_to_promise::<_, device::UserDevices>(async move {
-            Ok(me.get_user_devices(&user_id, None).await.map(Into::into)?)
+            // wait for up to a second for any in-flight device list requests to complete.
+            // The reason for this isn't so much to avoid races (some level of raciness is
+            // inevitable for this method) but to make testing easier.
+            Ok(me.get_user_devices(&user_id, Some(Duration::from_secs(1))).await.map(Into::into)?)
         })
     }