core: Move 4 test cases from DnsNameResolverTest to DnsNameResolverProviderTest (#12605)

These test cases make use of DnsNameResolverProvider but also cover some
logic from DnsNameResolverProvider's ctor. They could reasonably live in
either file but DnsNameResolverProviderTest already knows how to test
the new RFC 3986 newNameResolver() overload.

Leaves DnsNameResolverTest.java without any `java.net.URI` usage, which
makes sense because DnsNameResolver's public API does not mention
java.net.URI.

Removed test helpers that asserted more than "a single conceptual fact"
per

https://abseil.io/resources/swe-book/html/ch12.html#shared_helpers_and_validation

Author: jdcormie

core/src/test/java/io/grpc/internal/DnsNameResolverProviderTest.java

@@ -18,6 +18,7 @@
 
 import static com.google.common.truth.Truth.assertThat;
 import static com.google.common.truth.TruthJUnit.assume;
+import static org.junit.Assert.assertThrows;
 import static org.junit.Assert.assertTrue;
 import static org.mockito.Mockito.mock;
 
@@ -75,6 +76,7 @@ public void newNameResolver_acceptsHostAndPort() {
     assertThat(nameResolver).isNotNull();
     assertThat(nameResolver.getClass()).isSameInstanceAs(DnsNameResolver.class);
     assertThat(nameResolver.getServiceAuthority()).isEqualTo("localhost:443");
+    assertThat(((DnsNameResolver) nameResolver).getPort()).isEqualTo(443);
   }
 
   @Test
@@ -92,6 +94,15 @@ public void newNameResolver_rejectsNonDnsScheme() {
     assertThat(nameResolver).isNull();
   }
 
+  @Test
+  public void newNameResolver_validDnsNameWithoutPort_usesDefaultPort() {
+    DnsNameResolver nameResolver =
+        (DnsNameResolver) newNameResolver("dns:/foo.googleapis.com", args);
+    assertThat(nameResolver).isNotNull();
+    assertThat(nameResolver.getServiceAuthority()).isEqualTo("foo.googleapis.com");
+    assertThat(nameResolver.getPort()).isEqualTo(args.getDefaultPort());
+  }
+
   @Test
   public void newNameResolver_toleratesTrailingPathSegments() {
     NameResolver nameResolver = newNameResolver("dns:///foo.googleapis.com/ig/nor/ed", args);
@@ -108,6 +119,22 @@ public void newNameResolver_toleratesAuthority() {
     assertThat(nameResolver.getServiceAuthority()).isEqualTo("foo.googleapis.com");
   }
 
+  @Test
+  public void newNameResolver_validIpv6Host() {
+    NameResolver nameResolver = newNameResolver("dns:/%5B::1%5D", args);
+    assertThat(nameResolver).isNotNull();
+    assertThat(nameResolver.getClass()).isSameInstanceAs(DnsNameResolver.class);
+    assertThat(nameResolver.getServiceAuthority()).isEqualTo("[::1]");
+  }
+
+  @Test
+  public void newNameResolver_invalidIpv6Host_throws() {
+    IllegalArgumentException e =
+        assertThrows(
+            IllegalArgumentException.class, () -> newNameResolver("dns:/%5Binvalid%5D", args));
+    assertThat(e).hasMessageThat().contains("invalid");
+  }
+
   private NameResolver newNameResolver(String uriString, NameResolver.Args args) {
     return enableRfc3986UrisParam
         ? provider.newNameResolver(Uri.create(uriString), args)

core/src/test/java/io/grpc/internal/DnsNameResolverTest.java

@@ -64,7 +64,6 @@
 import java.net.InetAddress;
 import java.net.InetSocketAddress;
 import java.net.SocketAddress;
-import java.net.URI;
 import java.net.UnknownHostException;
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -112,7 +111,6 @@ public void uncaughtException(Thread t, Throwable e) {
         }
       });
 
-  private final DnsNameResolverProvider provider = new DnsNameResolverProvider();
   private final FakeClock fakeClock = new FakeClock();
   private final FakeClock fakeExecutor = new FakeClock();
   private static final FakeClock.TaskFilter NAME_RESOLVER_REFRESH_TASK_FILTER =
@@ -139,15 +137,6 @@ public Executor create() {
     public void close(Executor instance) {}
   }
 
-  private final NameResolver.Args args = NameResolver.Args.newBuilder()
-      .setDefaultPort(DEFAULT_PORT)
-      .setProxyDetector(GrpcUtil.DEFAULT_PROXY_DETECTOR)
-      .setSynchronizationContext(syncContext)
-      .setServiceConfigParser(mock(ServiceConfigParser.class))
-      .setChannelLogger(mock(ChannelLogger.class))
-      .setScheduledExecutorService(fakeExecutor.getScheduledExecutorService())
-      .build();
-
   @Mock
   private NameResolver.Listener2 mockListener;
   @Captor
@@ -167,6 +156,7 @@ private RetryingNameResolver newResolver(String name, int defaultPort, boolean i
         isAndroid);
   }
 
+
   private RetryingNameResolver newResolver(
       String name,
       int defaultPort,
@@ -216,28 +206,6 @@ public void setUp() {
     when(mockListener.onResult2(isA(ResolutionResult.class))).thenReturn(Status.OK);
   }
 
-  @Test
-  public void invalidDnsName() throws Exception {
-    testInvalidUri(new URI("dns", null, "/[invalid]", null));
-  }
-
-  @Test
-  public void validIpv6() throws Exception {
-    testValidUri(new URI("dns", null, "/[::1]", null), "[::1]", DEFAULT_PORT);
-  }
-
-  @Test
-  public void validDnsNameWithoutPort() throws Exception {
-    testValidUri(new URI("dns", null, "/foo.googleapis.com", null),
-        "foo.googleapis.com", DEFAULT_PORT);
-  }
-
-  @Test
-  public void validDnsNameWithPort() throws Exception {
-    testValidUri(new URI("dns", null, "/foo.googleapis.com:456", null),
-        "foo.googleapis.com:456", 456);
-  }
-
   @Test
   public void nullDnsName() {
     try {
@@ -1284,22 +1252,6 @@ public void parseServiceConfig_matches() {
     assertThat(result.getConfig()).isEqualTo(ImmutableMap.of());
   }
 
-  private void testInvalidUri(URI uri) {
-    try {
-      provider.newNameResolver(uri, args);
-      fail("Should have failed");
-    } catch (IllegalArgumentException e) {
-      // expected
-    }
-  }
-
-  private void testValidUri(URI uri, String exportedAuthority, int expectedPort) {
-    DnsNameResolver resolver = (DnsNameResolver) provider.newNameResolver(uri, args);
-    assertNotNull(resolver);
-    assertEquals(expectedPort, resolver.getPort());
-    assertEquals(exportedAuthority, resolver.getServiceAuthority());
-  }
-
   private byte lastByte = 0;
 
   private List<InetAddress> createAddressList(int n) throws UnknownHostException {