From 5f45a3742ae13550f7105cf0841668cdb319cdb1 Mon Sep 17 00:00:00 2001
From: Patrick Rohr <prohr@google.com>
Date: Wed, 18 May 2022 16:42:05 -0700
Subject: [PATCH] Always wait for interface to be up in EthernetManagerTest

Adds a global listener that is used to wait for an interface to show up
in EthernetTracker when it is newly created. This prevents races when
the interface is used directly after creation.

This test should fix the testCallback flakes.

Test: atest EthernetManagerTest
Bug: 227008268
Change-Id: I37d2ec63aea9f4de6010e13150bc236ee07e2f85
---
 .../android/net/cts/EthernetManagerTest.kt    | 29 ++++++++++++-------
 1 file changed, 18 insertions(+), 11 deletions(-)

diff --git a/tests/cts/net/src/android/net/cts/EthernetManagerTest.kt b/tests/cts/net/src/android/net/cts/EthernetManagerTest.kt
index a16a7f8fa1..792aa8373a 100644
--- a/tests/cts/net/src/android/net/cts/EthernetManagerTest.kt
+++ b/tests/cts/net/src/android/net/cts/EthernetManagerTest.kt
@@ -53,10 +53,9 @@ import org.junit.Rule
 import org.junit.Test
 import org.junit.runner.RunWith
 import java.net.Inet6Address
-import java.net.NetworkInterface
-import java.util.concurrent.Executor
 import kotlin.test.assertEquals
 import kotlin.test.assertFalse
+import kotlin.test.assertNotNull
 import kotlin.test.assertNull
 import kotlin.test.assertTrue
 import kotlin.test.fail
@@ -76,6 +75,7 @@ class EthernetManagerTest {
     private val context by lazy { InstrumentationRegistry.getInstrumentation().context }
     private val em by lazy { EthernetManagerShimImpl.newInstance(context) }
 
+    private val ifaceListener = EthernetStateListener()
     private val createdIfaces = ArrayList<EthernetTestInterface>()
     private val addedListeners = ArrayList<EthernetStateListener>()
 
@@ -154,6 +154,12 @@ class EthernetManagerTest {
             return events.poll(TIMEOUT_MS) ?: fail("Did not receive callback after ${TIMEOUT_MS}ms")
         }
 
+        fun eventuallyExpect(expected: CallbackEntry) = events.poll(TIMEOUT_MS) { it == expected }
+
+        fun eventuallyExpect(iface: EthernetTestInterface, state: Int, role: Int) {
+            assertNotNull(eventuallyExpect(createChangeEvent(iface, state, role)))
+        }
+
         fun assertNoCallback() {
             val cb = events.poll(NO_CALLBACK_TIMEOUT_MS)
             assertNull(cb, "Expected no callback but got $cb")
@@ -163,6 +169,7 @@ class EthernetManagerTest {
     @Before
     fun setUp() {
         setIncludeTestInterfaces(true)
+        addInterfaceStateListener(ifaceListener)
     }
 
     @After
@@ -176,18 +183,20 @@ class EthernetManagerTest {
         }
     }
 
-    private fun addInterfaceStateListener(executor: Executor, listener: EthernetStateListener) {
+    private fun addInterfaceStateListener(listener: EthernetStateListener) {
         runAsShell(CONNECTIVITY_USE_RESTRICTED_NETWORKS) {
-            em.addInterfaceStateListener(executor, listener)
+            em.addInterfaceStateListener(HandlerExecutor(Handler(Looper.getMainLooper())), listener)
         }
         addedListeners.add(listener)
     }
 
     private fun createInterface(): EthernetTestInterface {
-        return EthernetTestInterface(
+        val iface = EthernetTestInterface(
             context,
             Handler(Looper.getMainLooper())
         ).also { createdIfaces.add(it) }
+        ifaceListener.eventuallyExpect(iface, STATE_LINK_UP, ROLE_CLIENT)
+        return iface
     }
 
     private fun setIncludeTestInterfaces(value: Boolean) {
@@ -203,12 +212,10 @@ class EthernetManagerTest {
 
     @Test
     fun testCallbacks() {
-        val executor = HandlerExecutor(Handler(Looper.getMainLooper()))
-
         // If an interface exists when the callback is registered, it is reported on registration.
         val iface = createInterface()
         val listener1 = EthernetStateListener()
-        addInterfaceStateListener(executor, listener1)
+        addInterfaceStateListener(listener1)
         validateListenerOnRegistration(listener1)
 
         // If an interface appears, existing callbacks see it.
@@ -221,18 +228,18 @@ class EthernetManagerTest {
 
         // Register a new listener, it should see state of all existing interfaces immediately.
         val listener2 = EthernetStateListener()
-        addInterfaceStateListener(executor, listener2)
+        addInterfaceStateListener(listener2)
         validateListenerOnRegistration(listener2)
 
         // Removing interfaces first sends link down, then STATE_ABSENT/ROLE_NONE.
         removeInterface(iface)
-        for (listener in addedListeners) {
+        for (listener in listOf(listener1, listener2)) {
             listener.expectCallback(iface, STATE_LINK_DOWN, ROLE_CLIENT)
             listener.expectCallback(iface, STATE_ABSENT, ROLE_NONE)
         }
 
         removeInterface(iface2)
-        for (listener in addedListeners) {
+        for (listener in listOf(listener1, listener2)) {
             listener.expectCallback(iface2, STATE_LINK_DOWN, ROLE_CLIENT)
             listener.expectCallback(iface2, STATE_ABSENT, ROLE_NONE)
             listener.assertNoCallback()