Factorize custom asserts.

Also a few utilities that were in the way, and some opportunistic
cleanups.

Test: FrameworksNetTest NetworkStackTest
Change-Id: I385070e2044fd967cb18f1ffea9a86a4627b742e
diff --git a/tests/net/java/com/android/server/connectivity/tethering/OffloadControllerTest.java b/tests/net/java/com/android/server/connectivity/tethering/OffloadControllerTest.java
index 762b76c..9931aec 100644
--- a/tests/net/java/com/android/server/connectivity/tethering/OffloadControllerTest.java
+++ b/tests/net/java/com/android/server/connectivity/tethering/OffloadControllerTest.java
@@ -25,6 +25,7 @@
 import static android.provider.Settings.Global.TETHER_OFFLOAD_DISABLED;
 
 import static com.android.server.connectivity.tethering.OffloadHardwareInterface.ForwardedStats;
+import static com.android.testutils.MiscAssertsKt.assertContainsAll;
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertTrue;
@@ -244,7 +245,7 @@
         inOrder.verify(mHardware, times(1)).setLocalPrefixes(mStringArrayCaptor.capture());
         ArrayList<String> localPrefixes = mStringArrayCaptor.getValue();
         assertEquals(4, localPrefixes.size());
-        assertArrayListContains(localPrefixes,
+        assertContainsAll(localPrefixes,
                 "127.0.0.0/8", "192.0.2.0/24", "fe80::/64", "2001:db8::/64");
         inOrder.verifyNoMoreInteractions();
 
@@ -360,7 +361,7 @@
         inOrder.verify(mHardware, times(1)).setLocalPrefixes(mStringArrayCaptor.capture());
         localPrefixes = mStringArrayCaptor.getValue();
         assertEquals(6, localPrefixes.size());
-        assertArrayListContains(localPrefixes,
+        assertContainsAll(localPrefixes,
                 "127.0.0.0/8", "192.0.2.0/24", "fe80::/64", "2001:db8::/64",
                 "2001:db8::6173:7369:676e:6564/128", "2001:db8::7261:6e64:6f6d/128");
         // The relevant parts of the LinkProperties have not changed, but at the
@@ -717,7 +718,7 @@
         verify(mHardware, times(1)).setLocalPrefixes(mStringArrayCaptor.capture());
         ArrayList<String> localPrefixes = mStringArrayCaptor.getValue();
         assertEquals(4, localPrefixes.size());
-        assertArrayListContains(localPrefixes,
+        assertContainsAll(localPrefixes,
                 // TODO: The logic to find and exclude downstream IP prefixes
                 // is currently in Tethering's OffloadWrapper but must be moved
                 // into OffloadController proper. After this, also check for:
@@ -730,9 +731,4 @@
         verifyNoMoreInteractions(mHardware);
     }
 
-    private static void assertArrayListContains(ArrayList<String> list, String... elems) {
-        for (String element : elems) {
-            assertTrue(element + " not in list", list.contains(element));
-        }
-    }
 }