Fix flaky test: testSetOemNetworkPreferenceForTestPref

- waitForAvailable is checking the NetworkCapabilities that has
  target transport. But calling getNetworkCapabilities in
  available callback is not correct because it should not use
  sync call in async call. Instead, it should wait for
  capabilities callback to check the transport.
- The other callbacks (LP or NC changes) would receive before LOST
  callback. Thus, use eventuallyExpect to replace expectCallback.

Bug: 264769746
Test: atest android.net.cts.ConnectivityManagerTest --iteration
Change-Id: Iaad7a74717c81f3e6236d21981f8a5449b5a6f25
diff --git a/tests/cts/net/src/android/net/cts/ConnectivityManagerTest.java b/tests/cts/net/src/android/net/cts/ConnectivityManagerTest.java
index 774176f..48ec9c6 100644
--- a/tests/cts/net/src/android/net/cts/ConnectivityManagerTest.java
+++ b/tests/cts/net/src/android/net/cts/ConnectivityManagerTest.java
@@ -2176,15 +2176,12 @@
                 c -> c instanceof CallbackEntry.Available);
     }
 
-    private void waitForAvailable(
+    private void waitForTransport(
             @NonNull final TestableNetworkCallback cb, final int expectedTransport) {
-        cb.eventuallyExpect(
-                CallbackEntry.AVAILABLE, NETWORK_CALLBACK_TIMEOUT_MS,
-                entry -> {
-                    final NetworkCapabilities nc = mCm.getNetworkCapabilities(entry.getNetwork());
-                    return nc.hasTransport(expectedTransport);
-                }
-        );
+        cb.eventuallyExpect(CallbackEntry.NETWORK_CAPS_UPDATED,
+                NETWORK_CALLBACK_TIMEOUT_MS,
+                entry -> ((CallbackEntry.CapabilitiesChanged) entry).getCaps()
+                        .hasTransport(expectedTransport));
     }
 
     private void waitForAvailable(
@@ -2672,7 +2669,8 @@
 
             // Validate that an unmetered network is used over other networks.
             waitForAvailable(defaultCallback, wifiNetwork);
-            waitForAvailable(systemDefaultCallback, wifiNetwork);
+            systemDefaultCallback.eventuallyExpect(CallbackEntry.AVAILABLE,
+                    NETWORK_CALLBACK_TIMEOUT_MS, cb -> wifiNetwork.equals(cb.getNetwork()));
 
             // Validate that when setting unmetered to metered, unmetered is lost and replaced by
             // the network with the TEST transport. Also wait for validation here, in case there
@@ -2684,11 +2682,14 @@
             // callbacks may be received. Eventually, metered Wi-Fi should be the final available
             // callback in any case therefore confirm its receipt before continuing to assure the
             // system is in the expected state.
-            waitForAvailable(systemDefaultCallback, TRANSPORT_WIFI);
+            waitForTransport(systemDefaultCallback, TRANSPORT_WIFI);
         }, /* cleanup */ () -> {
-            // Validate that removing the test network will fallback to the default network.
+                // Validate that removing the test network will fallback to the default network.
                 runWithShellPermissionIdentity(tnt::teardown);
-                defaultCallback.expect(CallbackEntry.LOST, tnt, NETWORK_CALLBACK_TIMEOUT_MS);
+                // The other callbacks (LP or NC changes) would receive before LOST callback. Use
+                // eventuallyExpect to check callback for avoiding test flake.
+                defaultCallback.eventuallyExpect(CallbackEntry.LOST, NETWORK_CALLBACK_TIMEOUT_MS,
+                        lost -> tnt.getNetwork().equals(lost.getNetwork()));
                 waitForAvailable(defaultCallback);
             }, /* cleanup */ () -> {
                 setWifiMeteredStatusAndWait(ssid, oldMeteredValue, false /* waitForValidation */);