diff --git a/tests/net/java/com/android/server/connectivity/MultipathPolicyTrackerTest.java b/tests/net/java/com/android/server/connectivity/MultipathPolicyTrackerTest.java
index c53462c..950d716 100644
--- a/tests/net/java/com/android/server/connectivity/MultipathPolicyTrackerTest.java
+++ b/tests/net/java/com/android/server/connectivity/MultipathPolicyTrackerTest.java
@@ -130,6 +130,7 @@
 
         when(mContext.getResources()).thenReturn(mResources);
         when(mContext.getApplicationInfo()).thenReturn(new ApplicationInfo());
+        // Mock user id to all users that Context#registerReceiver will register with all users too.
         doReturn(UserHandle.ALL.getIdentifier()).when(mUserAllContext).getUserId();
         when(mContext.createContextAsUser(eq(UserHandle.ALL), anyInt()))
                 .thenReturn(mUserAllContext);