diff --git a/tests/10apidoc/12device_management.pl b/tests/10apidoc/12device_management.pl
index 100fb402d..73e13833b 100644
--- a/tests/10apidoc/12device_management.pl
+++ b/tests/10apidoc/12device_management.pl
@@ -1,4 +1,4 @@
-our @EXPORT = qw( matrix_get_device );
+our @EXPORT = qw( matrix_get_device matrix_set_device_display_name );
 
 sub matrix_get_device {
    my ( $user, $device_id ) = @_;
@@ -10,6 +10,19 @@ sub matrix_get_device {
    );
 }
 
+sub matrix_set_device_display_name {
+    my ( $user, $device_id, $display_name ) = @_;
+
+    return do_request_json_for(
+        $user,
+        method => "PUT",
+        uri    => "/unstable/devices/${device_id}",
+        content => {
+            display_name => $display_name,
+        },
+    );
+}
+
 test "GET /device/{deviceId}",
    requires => [ local_user_fixture( with_events => 0 ) ],
 
diff --git a/tests/41end-to-end-keys/01-upload-key.pl b/tests/41end-to-end-keys/01-upload-key.pl
index bcbb0282f..033591981 100644
--- a/tests/41end-to-end-keys/01-upload-key.pl
+++ b/tests/41end-to-end-keys/01-upload-key.pl
@@ -53,6 +53,8 @@
       )->then( sub {
          my ( $content ) = @_;
 
+         log_if_fail( "/query response", $content );
+
          assert_json_keys( $content, "device_keys" );
 
          my $device_keys = $content->{device_keys};
@@ -60,7 +62,20 @@
 
          my $alice_keys = $device_keys->{ $user->user_id };
          assert_json_keys( $alice_keys, $user->device_id );
+
+         my $alice_device_keys = $alice_keys->{ $user->device_id };
+         assert_json_keys( $alice_device_keys, "unsigned" );
+
+         my $unsigned = $alice_device_keys->{unsigned};
+
+         # display_name should be null by default
+         exists $unsigned->{device_display_name} or
+           die "Expected to get a (null) device_display_name";
+         defined $unsigned->{device_display_name} and
+           die "Device display name was unexpectedly defined.";
+
          # TODO: Check that the content matches what we uploaded.
+
          Future->done(1)
       })
    };
diff --git a/tests/41end-to-end-keys/04-query-key-federation.pl b/tests/41end-to-end-keys/04-query-key-federation.pl
index 56215e431..3f173f973 100644
--- a/tests/41end-to-end-keys/04-query-key-federation.pl
+++ b/tests/41end-to-end-keys/04-query-key-federation.pl
@@ -8,6 +8,8 @@
       matrix_put_e2e_keys( $user )
          ->SyTest::pass_on_done( "Uploaded key" )
       ->then( sub {
+         matrix_set_device_display_name( $user, $user->device_id, "test display name" ),
+      })->then( sub {
          do_request_json_for( $remote_user,
             method  => "POST",
             uri     => "/unstable/keys/query/",
@@ -27,7 +29,14 @@
 
          my $alice_keys = $device_keys->{ $user->user_id };
          assert_json_keys( $alice_keys, $user->device_id );
+
+         my $alice_device_keys = $alice_keys->{ $user->device_id };
+
          # TODO: Check that the content matches what we uploaded.
+
+         assert_eq( $alice_device_keys->{"unsigned"}->{"device_display_name"},
+                    "test display name" );
+
          Future->done(1)
       });
    };