From 54fa56def5a8f684d9c11252486e8a26936c37b5 Mon Sep 17 00:00:00 2001
From: Mark Chien <markchien@google.com>
Date: Tue, 2 Apr 2024 04:27:04 +0000
Subject: [PATCH] Move setupOnce from EthernetTetheringTestBase to
 EthernetTetheringTest

If we want to get rid of the flakiness, we may need to change the
production code. You can find a more detailed analysis in
b/318121782/comment#4.

Here's a quick and easy alternative fix: just move setupOnce from
EthernetTetheringTestBase to EthernetTetheringTest. The flakiness
started when I added setupOnce into EthernetTetheringTestBase to
fix flakiness in EthernetTetheringTest.

Bug: 318121782
Test: TH
Change-Id: I0a6fb25773aa60872f71fe4b34e42a0b745a767f
---
 .../net/EthernetTetheringTestBase.java        | 31 +------------------
 .../android/net/EthernetTetheringTest.java    | 30 ++++++++++++++++++
 2 files changed, 31 insertions(+), 30 deletions(-)

diff --git a/Tethering/tests/integration/base/android/net/EthernetTetheringTestBase.java b/Tethering/tests/integration/base/android/net/EthernetTetheringTestBase.java
index f6968850a9..120b8711d8 100644
--- a/Tethering/tests/integration/base/android/net/EthernetTetheringTestBase.java
+++ b/Tethering/tests/integration/base/android/net/EthernetTetheringTestBase.java
@@ -74,7 +74,6 @@ import com.android.testutils.TestNetworkTracker;
 
 import org.junit.After;
 import org.junit.Before;
-import org.junit.BeforeClass;
 
 import java.io.FileDescriptor;
 import java.net.Inet4Address;
@@ -144,7 +143,7 @@ public abstract class EthernetTetheringTestBase {
 
     private static final Context sContext =
             InstrumentationRegistry.getInstrumentation().getContext();
-    private static final EthernetManager sEm = sContext.getSystemService(EthernetManager.class);
+    protected static final EthernetManager sEm = sContext.getSystemService(EthernetManager.class);
     private static final TetheringManager sTm = sContext.getSystemService(TetheringManager.class);
     private static final PackageManager sPackageManager = sContext.getPackageManager();
     private static final CtsNetUtils sCtsNetUtils = new CtsNetUtils(sContext);
@@ -168,34 +167,6 @@ public abstract class EthernetTetheringTestBase {
         return sContext;
     }
 
-    @BeforeClass
-    public static void setUpOnce() throws Exception {
-        // The first test case may experience tethering restart with IP conflict handling.
-        // Tethering would cache the last upstreams so that the next enabled tethering avoids
-        // picking up the address that is in conflict with the upstreams. To protect subsequent
-        // tests, turn tethering on and off before running them.
-        MyTetheringEventCallback callback = null;
-        TestNetworkInterface testIface = null;
-        assumeTrue(sEm != null);
-        try {
-            // If the physical ethernet interface is available, do nothing.
-            if (isInterfaceForTetheringAvailable()) return;
-
-            testIface = createTestInterface();
-            setIncludeTestInterfaces(true);
-
-            callback = enableEthernetTethering(testIface.getInterfaceName(), null);
-            callback.awaitUpstreamChanged(true /* throwTimeoutException */);
-        } catch (TimeoutException e) {
-            Log.d(TAG, "WARNNING " + e);
-        } finally {
-            maybeCloseTestInterface(testIface);
-            maybeUnregisterTetheringEventCallback(callback);
-
-            setIncludeTestInterfaces(false);
-        }
-    }
-
     @Before
     public void setUp() throws Exception {
         mHandlerThread = new HandlerThread(getClass().getSimpleName());
diff --git a/Tethering/tests/integration/src/android/net/EthernetTetheringTest.java b/Tethering/tests/integration/src/android/net/EthernetTetheringTest.java
index 4949eaa9e2..c54d1b4d54 100644
--- a/Tethering/tests/integration/src/android/net/EthernetTetheringTest.java
+++ b/Tethering/tests/integration/src/android/net/EthernetTetheringTest.java
@@ -59,6 +59,7 @@ import com.android.testutils.DevSdkIgnoreRule.IgnoreUpTo;
 import com.android.testutils.NetworkStackModuleTest;
 import com.android.testutils.TapPacketReader;
 
+import org.junit.BeforeClass;
 import org.junit.Rule;
 import org.junit.Test;
 import org.junit.runner.RunWith;
@@ -150,6 +151,35 @@ public class EthernetTetheringTest extends EthernetTetheringTestBase {
             (byte) 0x01, (byte) 0x02, (byte) 0x03, (byte) 0x04  /* Address: 1.2.3.4 */
     };
 
+    /** Enable/disable tethering once before running the tests. */
+    @BeforeClass
+    public static void setUpOnce() throws Exception {
+        // The first test case may experience tethering restart with IP conflict handling.
+        // Tethering would cache the last upstreams so that the next enabled tethering avoids
+        // picking up the address that is in conflict with the upstreams. To protect subsequent
+        // tests, turn tethering on and off before running them.
+        MyTetheringEventCallback callback = null;
+        TestNetworkInterface testIface = null;
+        assumeTrue(sEm != null);
+        try {
+            // If the physical ethernet interface is available, do nothing.
+            if (isInterfaceForTetheringAvailable()) return;
+
+            testIface = createTestInterface();
+            setIncludeTestInterfaces(true);
+
+            callback = enableEthernetTethering(testIface.getInterfaceName(), null);
+            callback.awaitUpstreamChanged(true /* throwTimeoutException */);
+        } catch (TimeoutException e) {
+            Log.d(TAG, "WARNNING " + e);
+        } finally {
+            maybeCloseTestInterface(testIface);
+            maybeUnregisterTetheringEventCallback(callback);
+
+            setIncludeTestInterfaces(false);
+        }
+    }
+
     @Test
     public void testVirtualEthernetAlreadyExists() throws Exception {
         // This test requires manipulating packets. Skip if there is a physical Ethernet connected.