From 1a8c6c1728d8e91ba75240f4ef91f7cd07756bbd Mon Sep 17 00:00:00 2001
From: Andrew Morgan <andrew@amorgan.xyz>
Date: Thu, 10 Feb 2022 18:21:54 +0000
Subject: [PATCH 1/2] Add a test for device list updates of local users coming
 down /sync

---
 tests/csapi/device_lists_test.go | 66 ++++++++++++++++++++++++++++++++
 1 file changed, 66 insertions(+)
 create mode 100644 tests/csapi/device_lists_test.go

diff --git a/tests/csapi/device_lists_test.go b/tests/csapi/device_lists_test.go
new file mode 100644
index 00000000..b80ac156
--- /dev/null
+++ b/tests/csapi/device_lists_test.go
@@ -0,0 +1,66 @@
+package csapi_tests
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/matrix-org/complement/internal/b"
+	"github.com/matrix-org/complement/internal/client"
+
+	"github.com/tidwall/gjson"
+)
+
+// TestLocalUsersReceiveDeviceListUpdates tests that users on the same
+// homeserver receive device list updates from other local users, as
+// long as they share a room.
+func TestLocalUsersReceiveDeviceListUpdates(t *testing.T) {
+	// Create a homeserver with two users that share a room
+	deployment := Deploy(t, b.BlueprintOneToOneRoom)
+	defer deployment.Destroy(t)
+
+	// Get a reference to the already logged-in CS API clients for each user
+	alice := deployment.Client(t, "hs1", "@alice:hs1")
+	bob := deployment.Client(t, "hs1", "@bob:hs1")
+
+	// Deduce alice's device ID
+	resp := alice.MustDoFunc(
+		t,
+		"GET",
+		[]string{"_matrix", "client", "v3", "devices"},
+	)
+	responseBodyBytes := client.ParseJSON(t, resp)
+	aliceDeviceID := gjson.GetBytes(responseBodyBytes, "devices.0.device_id").Str
+
+	// Bob performs an initial sync
+	_, bobNextBatch := bob.MustSync(t, client.SyncReq{})
+
+	// Alice then updates their device list by renaming their current device
+	alice.MustDoFunc(
+		t,
+		"PUT",
+		[]string{"_matrix", "client", "v3", "devices", aliceDeviceID},
+		client.WithJSONBody(
+			t,
+			map[string]interface{}{
+				"display_name": "A New Device Name",
+			},
+		),
+	)
+
+	// Check that Bob received a device list update from Alice
+	bob.MustSyncUntil(
+		t,
+		client.SyncReq{
+			Since: bobNextBatch,
+		}, func(clientUserID string, topLevelSyncJSON gjson.Result) error {
+			// Ensure that Bob sees that Alice has updated their device list
+			usersWithChangedDeviceListsArray := topLevelSyncJSON.Get("device_lists.changed").Array()
+			for _, userID := range usersWithChangedDeviceListsArray {
+				if userID.Str == alice.UserID {
+					return nil
+				}
+			}
+			return fmt.Errorf("missing device list update for Alice")
+		},
+	)
+}

From 2d6ec9e236428cc008cf42913fea1c21ee32ff5c Mon Sep 17 00:00:00 2001
From: Andrew Morgan <andrewm@element.io>
Date: Tue, 15 Feb 2022 11:17:11 +0000
Subject: [PATCH 2/2] Switch to /whoami endpoint for device ID discovery

---
 tests/csapi/device_lists_test.go | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tests/csapi/device_lists_test.go b/tests/csapi/device_lists_test.go
index b80ac156..91fdb546 100644
--- a/tests/csapi/device_lists_test.go
+++ b/tests/csapi/device_lists_test.go
@@ -26,10 +26,10 @@ func TestLocalUsersReceiveDeviceListUpdates(t *testing.T) {
 	resp := alice.MustDoFunc(
 		t,
 		"GET",
-		[]string{"_matrix", "client", "v3", "devices"},
+		[]string{"_matrix", "client", "v3", "account", "whoami"},
 	)
 	responseBodyBytes := client.ParseJSON(t, resp)
-	aliceDeviceID := gjson.GetBytes(responseBodyBytes, "devices.0.device_id").Str
+	aliceDeviceID := gjson.GetBytes(responseBodyBytes, "device_id").Str
 
 	// Bob performs an initial sync
 	_, bobNextBatch := bob.MustSync(t, client.SyncReq{})