Implement LB policy updates

11 files changed, 924 insertions, 374 deletions

diff --git a/test/core/client_channel/resolvers/BUILD b/test/core/client_channel/resolvers/BUILD
index 80ca7d3ebb..030f6091b5 100644
--- a/test/core/client_channel/resolvers/BUILD
+++ b/test/core/client_channel/resolvers/BUILD
@@ -74,7 +74,7 @@ grpc_cc_test(
     deps = [
         "//:gpr",
         "//:grpc",
-        "//test/core/end2end:fake_resolver",
+        "//:grpc_resolver_fake",
         "//test/core/util:gpr_test_util",
         "//test/core/util:grpc_test_util",
     ],
diff --git a/test/core/client_channel/resolvers/fake_resolver_test.c b/test/core/client_channel/resolvers/fake_resolver_test.c
index 861918fbd6..c211f26b76 100644
--- a/test/core/client_channel/resolvers/fake_resolver_test.c
+++ b/test/core/client_channel/resolvers/fake_resolver_test.c
@@ -39,18 +39,18 @@
 
 #include "src/core/ext/filters/client_channel/lb_policy_factory.h"
 #include "src/core/ext/filters/client_channel/parse_address.h"
+#include "src/core/ext/filters/client_channel/resolver/fake/fake_resolver.h"
 #include "src/core/ext/filters/client_channel/resolver_registry.h"
 #include "src/core/lib/channel/channel_args.h"
 #include "src/core/lib/iomgr/combiner.h"
 #include "src/core/lib/security/credentials/fake/fake_credentials.h"
 
-#include "test/core/end2end/fake_resolver.h"
 #include "test/core/util/test_config.h"
 
 static grpc_resolver *build_fake_resolver(
     grpc_exec_ctx *exec_ctx, grpc_combiner *combiner,
     grpc_fake_resolver_response_generator *response_generator) {
-  grpc_resolver_factory *factory = grpc_resolver_factory_lookup("test");
+  grpc_resolver_factory *factory = grpc_resolver_factory_lookup("fake");
   grpc_arg generator_arg =
       grpc_fake_resolver_response_generator_arg(response_generator);
   grpc_resolver_args args;
@@ -177,7 +177,6 @@ static void test_fake_resolver() {
 
 int main(int argc, char **argv) {
   grpc_test_init(argc, argv);
-  grpc_fake_resolver_init();  // Registers the "test" scheme.
   grpc_init();
 
   test_fake_resolver();
diff --git a/test/core/end2end/BUILD b/test/core/end2end/BUILD
index cf387a93e8..7705f62a79 100644
--- a/test/core/end2end/BUILD
+++ b/test/core/end2end/BUILD
@@ -59,18 +59,6 @@ grpc_cc_library(
     visibility = ["//test:__subpackages__"],
 )
 
-grpc_cc_library(
-    name = "fake_resolver",
-    srcs = ["fake_resolver.c"],
-    hdrs = ["fake_resolver.h"],
-    language = "C",
-    visibility = ["//test:__subpackages__"],
-    deps = [
-        "//:gpr",
-        "//:grpc",
-        "//test/core/util:grpc_test_util",
-    ],
-)
 
 grpc_cc_library(
     name = "http_proxy",
diff --git a/test/core/end2end/fake_resolver.c b/test/core/end2end/fake_resolver.c
deleted file mode 100644
index 736b224fd6..0000000000
--- a/test/core/end2end/fake_resolver.c
+++ /dev/null
@@ -1,253 +0,0 @@
-//
-// Copyright 2016, Google Inc.
-// All rights reserved.
-//
-// Redistribution and use in source and binary forms, with or without
-// modification, are permitted provided that the following conditions are
-// met:
-//
-//     * Redistributions of source code must retain the above copyright
-// notice, this list of conditions and the following disclaimer.
-//     * Redistributions in binary form must reproduce the above
-// copyright notice, this list of conditions and the following disclaimer
-// in the documentation and/or other materials provided with the
-// distribution.
-//     * Neither the name of Google Inc. nor the names of its
-// contributors may be used to endorse or promote products derived from
-// this software without specific prior written permission.
-//
-// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-//
-
-// This is similar to the sockaddr resolver, except that it supports a
-// bunch of query args that are useful for dependency injection in tests.
-
-#include <limits.h>
-#include <stdbool.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-
-#include <grpc/support/alloc.h>
-#include <grpc/support/host_port.h>
-#include <grpc/support/port_platform.h>
-#include <grpc/support/string_util.h>
-
-#include "src/core/ext/filters/client_channel/lb_policy_factory.h"
-#include "src/core/ext/filters/client_channel/parse_address.h"
-#include "src/core/ext/filters/client_channel/resolver_registry.h"
-#include "src/core/lib/channel/channel_args.h"
-#include "src/core/lib/iomgr/combiner.h"
-#include "src/core/lib/iomgr/resolve_address.h"
-#include "src/core/lib/iomgr/unix_sockets_posix.h"
-#include "src/core/lib/slice/slice_internal.h"
-#include "src/core/lib/slice/slice_string_helpers.h"
-#include "src/core/lib/support/string.h"
-
-#include "test/core/end2end/fake_resolver.h"
-
-//
-// fake_resolver
-//
-
-typedef struct {
-  // base class -- must be first
-  grpc_resolver base;
-
-  // passed-in parameters
-  grpc_channel_args* channel_args;
-
-  // If not NULL, the next set of resolution results to be returned to
-  // grpc_resolver_next_locked()'s closure.
-  grpc_channel_args* next_results;
-
-  // pending next completion, or NULL
-  grpc_closure* next_completion;
-  // target result address for next completion
-  grpc_channel_args** target_result;
-} fake_resolver;
-
-static void fake_resolver_destroy(grpc_exec_ctx* exec_ctx, grpc_resolver* gr) {
-  fake_resolver* r = (fake_resolver*)gr;
-  grpc_channel_args_destroy(exec_ctx, r->next_results);
-  grpc_channel_args_destroy(exec_ctx, r->channel_args);
-  gpr_free(r);
-}
-
-static void fake_resolver_shutdown_locked(grpc_exec_ctx* exec_ctx,
-                                          grpc_resolver* resolver) {
-  fake_resolver* r = (fake_resolver*)resolver;
-  if (r->next_completion != NULL) {
-    *r->target_result = NULL;
-    grpc_closure_sched(exec_ctx, r->next_completion, GRPC_ERROR_NONE);
-    r->next_completion = NULL;
-  }
-}
-
-static void fake_resolver_maybe_finish_next_locked(grpc_exec_ctx* exec_ctx,
-                                                   fake_resolver* r) {
-  if (r->next_completion != NULL && r->next_results != NULL) {
-    *r->target_result =
-        grpc_channel_args_merge(r->channel_args, r->next_results);
-    grpc_channel_args_destroy(exec_ctx, r->next_results);
-    grpc_closure_sched(exec_ctx, r->next_completion, GRPC_ERROR_NONE);
-    r->next_completion = NULL;
-    r->next_results = NULL;
-  }
-}
-
-static void fake_resolver_channel_saw_error_locked(grpc_exec_ctx* exec_ctx,
-                                                   grpc_resolver* resolver) {
-  fake_resolver* r = (fake_resolver*)resolver;
-  fake_resolver_maybe_finish_next_locked(exec_ctx, r);
-}
-
-static void fake_resolver_next_locked(grpc_exec_ctx* exec_ctx,
-                                      grpc_resolver* resolver,
-                                      grpc_channel_args** target_result,
-                                      grpc_closure* on_complete) {
-  fake_resolver* r = (fake_resolver*)resolver;
-  GPR_ASSERT(!r->next_completion);
-  r->next_completion = on_complete;
-  r->target_result = target_result;
-  fake_resolver_maybe_finish_next_locked(exec_ctx, r);
-}
-
-static const grpc_resolver_vtable fake_resolver_vtable = {
-    fake_resolver_destroy, fake_resolver_shutdown_locked,
-    fake_resolver_channel_saw_error_locked, fake_resolver_next_locked};
-
-struct grpc_fake_resolver_response_generator {
-  fake_resolver* resolver;  // Set by the fake_resolver constructor to itself.
-  grpc_channel_args* next_response;
-  gpr_refcount refcount;
-};
-
-grpc_fake_resolver_response_generator*
-grpc_fake_resolver_response_generator_create() {
-  grpc_fake_resolver_response_generator* generator =
-      (grpc_fake_resolver_response_generator*)gpr_zalloc(sizeof(*generator));
-  gpr_ref_init(&generator->refcount, 1);
-  return generator;
-}
-
-grpc_fake_resolver_response_generator*
-grpc_fake_resolver_response_generator_ref(
-    grpc_fake_resolver_response_generator* generator) {
-  gpr_ref(&generator->refcount);
-  return generator;
-}
-
-void grpc_fake_resolver_response_generator_unref(
-    grpc_fake_resolver_response_generator* generator) {
-  if (gpr_unref(&generator->refcount)) {
-    gpr_free(generator);
-  }
-}
-
-static void set_response_cb(grpc_exec_ctx* exec_ctx, void* arg,
-                            grpc_error* error) {
-  grpc_fake_resolver_response_generator* generator =
-      (grpc_fake_resolver_response_generator*)arg;
-  fake_resolver* r = generator->resolver;
-  if (r->next_results != NULL) {
-    grpc_channel_args_destroy(exec_ctx, r->next_results);
-  }
-  r->next_results = generator->next_response;
-  fake_resolver_maybe_finish_next_locked(exec_ctx, r);
-}
-
-void grpc_fake_resolver_response_generator_set_response(
-    grpc_exec_ctx* exec_ctx, grpc_fake_resolver_response_generator* generator,
-    grpc_channel_args* next_response) {
-  GPR_ASSERT(generator->resolver != NULL);
-  generator->next_response = grpc_channel_args_copy(next_response);
-  grpc_closure_sched(
-      exec_ctx,
-      grpc_closure_create(
-          set_response_cb, generator,
-          grpc_combiner_scheduler(generator->resolver->base.combiner, false)),
-      GRPC_ERROR_NONE);
-}
-
-static void* response_generator_arg_copy(void* p) {
-  return grpc_fake_resolver_response_generator_ref(
-      (grpc_fake_resolver_response_generator*)p);
-}
-
-static void response_generator_arg_destroy(grpc_exec_ctx* exec_ctx, void* p) {
-  grpc_fake_resolver_response_generator_unref(
-      (grpc_fake_resolver_response_generator*)p);
-}
-
-static int response_generator_cmp(void* a, void* b) { return GPR_ICMP(a, b); }
-
-static const grpc_arg_pointer_vtable response_generator_arg_vtable = {
-    response_generator_arg_copy, response_generator_arg_destroy,
-    response_generator_cmp};
-
-grpc_arg grpc_fake_resolver_response_generator_arg(
-    grpc_fake_resolver_response_generator* generator) {
-  grpc_arg arg;
-  arg.type = GRPC_ARG_POINTER;
-  arg.key = GRPC_ARG_FAKE_RESOLVER_RESPONSE_GENERATOR;
-  arg.value.pointer.p = generator;
-  arg.value.pointer.vtable = &response_generator_arg_vtable;
-  return arg;
-}
-
-grpc_fake_resolver_response_generator*
-grpc_fake_resolver_get_response_generator(const grpc_channel_args* args) {
-  const grpc_arg* arg =
-      grpc_channel_args_find(args, GRPC_ARG_FAKE_RESOLVER_RESPONSE_GENERATOR);
-  if (arg == NULL || arg->type != GRPC_ARG_POINTER) return NULL;
-  return (grpc_fake_resolver_response_generator*)arg->value.pointer.p;
-}
-
-//
-// fake_resolver_factory
-//
-
-static void fake_resolver_factory_ref(grpc_resolver_factory* factory) {}
-
-static void fake_resolver_factory_unref(grpc_resolver_factory* factory) {}
-
-static grpc_resolver* fake_resolver_create(grpc_exec_ctx* exec_ctx,
-                                           grpc_resolver_factory* factory,
-                                           grpc_resolver_args* args) {
-  fake_resolver* r = (fake_resolver*)gpr_zalloc(sizeof(*r));
-  r->channel_args = grpc_channel_args_copy(args->args);
-  grpc_resolver_init(&r->base, &fake_resolver_vtable, args->combiner);
-  grpc_fake_resolver_response_generator* response_generator =
-      grpc_fake_resolver_get_response_generator(args->args);
-  if (response_generator != NULL) response_generator->resolver = r;
-  return &r->base;
-}
-
-static char* fake_resolver_get_default_authority(grpc_resolver_factory* factory,
-                                                 grpc_uri* uri) {
-  const char* path = uri->path;
-  if (path[0] == '/') ++path;
-  return gpr_strdup(path);
-}
-
-static const grpc_resolver_factory_vtable fake_resolver_factory_vtable = {
-    fake_resolver_factory_ref, fake_resolver_factory_unref,
-    fake_resolver_create, fake_resolver_get_default_authority, "test"};
-
-static grpc_resolver_factory fake_resolver_factory = {
-    &fake_resolver_factory_vtable};
-
-void grpc_fake_resolver_init(void) {
-  grpc_register_resolver_type(&fake_resolver_factory);
-}
diff --git a/test/core/end2end/fake_resolver.h b/test/core/end2end/fake_resolver.h
deleted file mode 100644
index d9668d0d11..0000000000
--- a/test/core/end2end/fake_resolver.h
+++ /dev/null
@@ -1,76 +0,0 @@
-//
-// Copyright 2016, Google Inc.
-// All rights reserved.
-//
-// Redistribution and use in source and binary forms, with or without
-// modification, are permitted provided that the following conditions are
-// met:
-//
-//     * Redistributions of source code must retain the above copyright
-// notice, this list of conditions and the following disclaimer.
-//     * Redistributions in binary form must reproduce the above
-// copyright notice, this list of conditions and the following disclaimer
-// in the documentation and/or other materials provided with the
-// distribution.
-//     * Neither the name of Google Inc. nor the names of its
-// contributors may be used to endorse or promote products derived from
-// this software without specific prior written permission.
-//
-// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-//
-
-#ifndef GRPC_TEST_CORE_END2END_FAKE_RESOLVER_H
-#define GRPC_TEST_CORE_END2END_FAKE_RESOLVER_H
-
-#include "src/core/ext/filters/client_channel/lb_policy_factory.h"
-#include "src/core/ext/filters/client_channel/uri_parser.h"
-#include "src/core/lib/channel/channel_args.h"
-
-#include "test/core/util/test_config.h"
-
-#define GRPC_ARG_FAKE_RESOLVER_RESPONSE_GENERATOR \
-  "grpc.fake_resolver.response_generator"
-
-void grpc_fake_resolver_init();
-
-// Instances of \a grpc_fake_resolver_response_generator are passed to the
-// fake resolver in a channel argument (see \a
-// grpc_fake_resolver_response_generator_arg) in order to inject and trigger
-// custom resolutions. See also \a
-// grpc_fake_resolver_response_generator_set_response.
-typedef struct grpc_fake_resolver_response_generator
-    grpc_fake_resolver_response_generator;
-grpc_fake_resolver_response_generator*
-grpc_fake_resolver_response_generator_create();
-
-// Instruct the fake resolver associated with the \a response_generator instance
-// to trigger a new resolution for \a uri and \a args.
-void grpc_fake_resolver_response_generator_set_response(
-    grpc_exec_ctx* exec_ctx, grpc_fake_resolver_response_generator* generator,
-    grpc_channel_args* next_response);
-
-// Return a \a grpc_arg for a \a grpc_fake_resolver_response_generator instance.
-grpc_arg grpc_fake_resolver_response_generator_arg(
-    grpc_fake_resolver_response_generator* generator);
-// Return the \a grpc_fake_resolver_response_generator instance in \a args or
-// NULL.
-grpc_fake_resolver_response_generator*
-grpc_fake_resolver_get_response_generator(const grpc_channel_args* args);
-
-grpc_fake_resolver_response_generator*
-grpc_fake_resolver_response_generator_ref(
-    grpc_fake_resolver_response_generator* generator);
-void grpc_fake_resolver_response_generator_unref(
-    grpc_fake_resolver_response_generator* generator);
-
-#endif /* GRPC_TEST_CORE_END2END_FAKE_RESOLVER_H */
diff --git a/test/core/end2end/generate_tests.bzl b/test/core/end2end/generate_tests.bzl
index 6865aefa3d..0adf7eb989 100755
--- a/test/core/end2end/generate_tests.bzl
+++ b/test/core/end2end/generate_tests.bzl
@@ -173,7 +173,6 @@ def grpc_end2end_tests():
     deps = [
       ':cq_verifier',
       ':ssl_test_data',
-      ':fake_resolver',
       ':http_proxy',
       ':proxy',
     ]
diff --git a/test/core/slice/slice_hash_table_test.c b/test/core/slice/slice_hash_table_test.c
index 67041b2d5c..16bfb424c3 100644
--- a/test/core/slice/slice_hash_table_test.c
+++ b/test/core/slice/slice_hash_table_test.c
@@ -77,6 +77,19 @@ static void destroy_string(grpc_exec_ctx* exec_ctx, void* value) {
   gpr_free(value);
 }
 
+static grpc_slice_hash_table* create_table_from_entries(
+    const test_entry* test_entries, size_t num_test_entries,
+    int (*value_cmp_fn)(void*, void*)) {
+  // Construct table.
+  grpc_slice_hash_table_entry* entries =
+      gpr_zalloc(sizeof(*entries) * num_test_entries);
+  populate_entries(test_entries, num_test_entries, entries);
+  grpc_slice_hash_table* table = grpc_slice_hash_table_create(
+      num_test_entries, entries, destroy_string, value_cmp_fn);
+  gpr_free(entries);
+  return table;
+}
+
 static void test_slice_hash_table() {
   const test_entry test_entries[] = {
       {"key_0", "value_0"},   {"key_1", "value_1"},   {"key_2", "value_2"},
@@ -115,13 +128,8 @@ static void test_slice_hash_table() {
       {"key_99", "value_99"},
   };
   const size_t num_entries = GPR_ARRAY_SIZE(test_entries);
-  // Construct table.
-  grpc_slice_hash_table_entry* entries =
-      gpr_zalloc(sizeof(*entries) * num_entries);
-  populate_entries(test_entries, num_entries, entries);
   grpc_slice_hash_table* table =
-      grpc_slice_hash_table_create(num_entries, entries, destroy_string);
-  gpr_free(entries);
+      create_table_from_entries(test_entries, num_entries, NULL);
   // Check contents of table.
   check_values(test_entries, num_entries, table);
   check_non_existent_value("XX", table);
@@ -131,8 +139,118 @@ static void test_slice_hash_table() {
   grpc_exec_ctx_finish(&exec_ctx);
 }
 
+static int value_cmp_fn(void* a, void* b) {
+  const char* a_str = a;
+  const char* b_str = b;
+  return strcmp(a_str, b_str);
+}
+
+static int pointer_cmp_fn(void* a, void* b) { return GPR_ICMP(a, b); }
+
+static void test_slice_hash_table_eq() {
+  const test_entry test_entries_a[] = {
+      {"key_0", "value_0"}, {"key_1", "value_1"}, {"key_2", "value_2"}};
+  const size_t num_entries_a = GPR_ARRAY_SIZE(test_entries_a);
+  grpc_slice_hash_table* table_a =
+      create_table_from_entries(test_entries_a, num_entries_a, value_cmp_fn);
+  GPR_ASSERT(grpc_slice_hash_table_cmp(table_a, table_a) == 0);
+
+  const test_entry test_entries_b[] = {
+      {"key_0", "value_0"}, {"key_1", "value_1"}, {"key_2", "value_2"}};
+  const size_t num_entries_b = GPR_ARRAY_SIZE(test_entries_b);
+  grpc_slice_hash_table* table_b =
+      create_table_from_entries(test_entries_b, num_entries_b, value_cmp_fn);
+
+  GPR_ASSERT(grpc_slice_hash_table_cmp(table_a, table_b) == 0);
+  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
+  grpc_slice_hash_table_unref(&exec_ctx, table_a);
+  grpc_slice_hash_table_unref(&exec_ctx, table_b);
+  grpc_exec_ctx_finish(&exec_ctx);
+}
+
+static void test_slice_hash_table_not_eq() {
+  const test_entry test_entries_a[] = {
+      {"key_0", "value_0"}, {"key_1", "value_1"}, {"key_2", "value_2"}};
+  const size_t num_entries_a = GPR_ARRAY_SIZE(test_entries_a);
+  grpc_slice_hash_table* table_a =
+      create_table_from_entries(test_entries_a, num_entries_a, value_cmp_fn);
+
+  // Different sizes.
+  const test_entry test_entries_b_smaller[] = {{"key_0", "value_0"},
+                                               {"key_1", "value_1"}};
+  const size_t num_entries_b_smaller = GPR_ARRAY_SIZE(test_entries_b_smaller);
+  grpc_slice_hash_table* table_b_smaller = create_table_from_entries(
+      test_entries_b_smaller, num_entries_b_smaller, value_cmp_fn);
+  GPR_ASSERT(grpc_slice_hash_table_cmp(table_a, table_b_smaller) > 0);
+
+  const test_entry test_entries_b_larger[] = {{"key_0", "value_0"},
+                                              {"key_1", "value_1"},
+                                              {"key_2", "value_2"},
+                                              {"key_3", "value_3"}};
+  const size_t num_entries_b_larger = GPR_ARRAY_SIZE(test_entries_b_larger);
+  grpc_slice_hash_table* table_b_larger = create_table_from_entries(
+      test_entries_b_larger, num_entries_b_larger, value_cmp_fn);
+  GPR_ASSERT(grpc_slice_hash_table_cmp(table_a, table_b_larger) < 0);
+
+  // One key doesn't match and is lexicographically "smaller".
+  const test_entry test_entries_c[] = {
+      {"key_zz", "value_0"}, {"key_1", "value_1"}, {"key_2", "value_2"}};
+  const size_t num_entries_c = GPR_ARRAY_SIZE(test_entries_c);
+  grpc_slice_hash_table* table_c =
+      create_table_from_entries(test_entries_c, num_entries_c, value_cmp_fn);
+  GPR_ASSERT(grpc_slice_hash_table_cmp(table_a, table_c) > 0);
+  GPR_ASSERT(grpc_slice_hash_table_cmp(table_c, table_a) < 0);
+
+  // One value doesn't match.
+  const test_entry test_entries_d[] = {
+      {"key_0", "value_z"}, {"key_1", "value_1"}, {"key_2", "value_2"}};
+  const size_t num_entries_d = GPR_ARRAY_SIZE(test_entries_d);
+  grpc_slice_hash_table* table_d =
+      create_table_from_entries(test_entries_d, num_entries_d, value_cmp_fn);
+  GPR_ASSERT(grpc_slice_hash_table_cmp(table_a, table_d) < 0);
+  GPR_ASSERT(grpc_slice_hash_table_cmp(table_d, table_a) > 0);
+
+  // Same values but different "equals" functions.
+  const test_entry test_entries_e[] = {
+      {"key_0", "value_0"}, {"key_1", "value_1"}, {"key_2", "value_2"}};
+  const size_t num_entries_e = GPR_ARRAY_SIZE(test_entries_e);
+  grpc_slice_hash_table* table_e =
+      create_table_from_entries(test_entries_e, num_entries_e, value_cmp_fn);
+  const test_entry test_entries_f[] = {
+      {"key_0", "value_0"}, {"key_1", "value_1"}, {"key_2", "value_2"}};
+  const size_t num_entries_f = GPR_ARRAY_SIZE(test_entries_f);
+  grpc_slice_hash_table* table_f =
+      create_table_from_entries(test_entries_f, num_entries_f, pointer_cmp_fn);
+  GPR_ASSERT(grpc_slice_hash_table_cmp(table_e, table_f) != 0);
+
+  // Same (empty) key, different values.
+  const test_entry test_entries_g[] = {{"", "value_0"}};
+  const size_t num_entries_g = GPR_ARRAY_SIZE(test_entries_g);
+  grpc_slice_hash_table* table_g =
+      create_table_from_entries(test_entries_g, num_entries_g, value_cmp_fn);
+  const test_entry test_entries_h[] = {{"", "value_1"}};
+  const size_t num_entries_h = GPR_ARRAY_SIZE(test_entries_h);
+  grpc_slice_hash_table* table_h =
+      create_table_from_entries(test_entries_h, num_entries_h, pointer_cmp_fn);
+  GPR_ASSERT(grpc_slice_hash_table_cmp(table_g, table_h) != 0);
+
+  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
+  grpc_slice_hash_table_unref(&exec_ctx, table_a);
+  grpc_slice_hash_table_unref(&exec_ctx, table_b_larger);
+  grpc_slice_hash_table_unref(&exec_ctx, table_b_smaller);
+  grpc_slice_hash_table_unref(&exec_ctx, table_c);
+  grpc_slice_hash_table_unref(&exec_ctx, table_d);
+  grpc_slice_hash_table_unref(&exec_ctx, table_e);
+  grpc_slice_hash_table_unref(&exec_ctx, table_f);
+  grpc_slice_hash_table_unref(&exec_ctx, table_g);
+  grpc_slice_hash_table_unref(&exec_ctx, table_h);
+  grpc_exec_ctx_finish(&exec_ctx);
+}
+
 int main(int argc, char** argv) {
   grpc_test_init(argc, argv);
   test_slice_hash_table();
+  test_slice_hash_table_eq();
+  test_slice_hash_table_not_eq();
   return 0;
 }
diff --git a/test/cpp/end2end/BUILD b/test/cpp/end2end/BUILD
index 9b691a83e0..97558d70bb 100644
--- a/test/cpp/end2end/BUILD
+++ b/test/cpp/end2end/BUILD
@@ -212,8 +212,8 @@ grpc_cc_test(
 )
 
 grpc_cc_test(
-    name = "round_robin_end2end_test",
-    srcs = ["round_robin_end2end_test.cc"],
+    name = "client_lb_end2end_test",
+    srcs = ["client_lb_end2end_test.cc"],
     deps = [
         ":test_service_impl",
         "//:gpr",
@@ -243,7 +243,7 @@ grpc_cc_test(
         "//src/proto/grpc/testing:echo_messages_proto",
         "//src/proto/grpc/testing:echo_proto",
         "//src/proto/grpc/testing/duplicate:echo_duplicate_proto",
-        "//test/core/end2end:fake_resolver",
+        "//:grpc_resolver_fake",
         "//test/core/util:gpr_test_util",
         "//test/core/util:grpc_test_util",
         "//test/cpp/util:test_util",
diff --git a/test/cpp/end2end/client_lb_end2end_test.cc b/test/cpp/end2end/client_lb_end2end_test.cc
new file mode 100644
index 0000000000..ff00225597
--- /dev/null
+++ b/test/cpp/end2end/client_lb_end2end_test.cc
@@ -0,0 +1,485 @@
+/*
+ *
+ * Copyright 2016, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include <algorithm>
+#include <memory>
+#include <mutex>
+#include <thread>
+
+#include <gtest/gtest.h>
+
+#include <grpc++/channel.h>
+#include <grpc++/client_context.h>
+#include <grpc++/create_channel.h>
+#include <grpc++/server.h>
+#include <grpc++/server_builder.h>
+#include <grpc/grpc.h>
+#include <grpc/support/alloc.h>
+#include <grpc/support/log.h>
+#include <grpc/support/string_util.h>
+#include <grpc/support/thd.h>
+#include <grpc/support/time.h>
+
+extern "C" {
+#include "src/core/ext/filters/client_channel/resolver/fake/fake_resolver.h"
+}
+
+#include "src/proto/grpc/testing/echo.grpc.pb.h"
+#include "test/core/util/port.h"
+#include "test/core/util/test_config.h"
+#include "test/cpp/end2end/test_service_impl.h"
+
+using grpc::testing::EchoRequest;
+using grpc::testing::EchoResponse;
+using std::chrono::system_clock;
+
+namespace grpc {
+namespace testing {
+namespace {
+
+// Subclass of TestServiceImpl that increments a request counter for
+// every call to the Echo RPC.
+class MyTestServiceImpl : public TestServiceImpl {
+ public:
+  MyTestServiceImpl() : request_count_(0) {}
+
+  Status Echo(ServerContext* context, const EchoRequest* request,
+              EchoResponse* response) override {
+    {
+      std::unique_lock<std::mutex> lock(mu_);
+      ++request_count_;
+    }
+    return TestServiceImpl::Echo(context, request, response);
+  }
+
+  int request_count() {
+    std::unique_lock<std::mutex> lock(mu_);
+    return request_count_;
+  }
+
+  void ResetCounters() {
+    std::unique_lock<std::mutex> lock(mu_);
+    request_count_ = 0;
+  }
+
+ private:
+  std::mutex mu_;
+  int request_count_;
+};
+
+class ClientLbEnd2endTest : public ::testing::Test {
+ protected:
+  ClientLbEnd2endTest() : server_host_("localhost") {}
+
+  void SetUp() override {
+    response_generator_ = grpc_fake_resolver_response_generator_create();
+  }
+
+  void TearDown() override {
+    grpc_fake_resolver_response_generator_unref(response_generator_);
+    for (size_t i = 0; i < servers_.size(); ++i) {
+      servers_[i]->Shutdown();
+    }
+  }
+
+  void StartServers(int num_servers) {
+    for (int i = 0; i < num_servers; ++i) {
+      servers_.emplace_back(new ServerData(server_host_));
+    }
+  }
+
+  void SetNextResolution(const std::vector<int>& ports) {
+    grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
+    grpc_lb_addresses* addresses = grpc_lb_addresses_create(ports.size(), NULL);
+    for (size_t i = 0; i < ports.size(); ++i) {
+      char* lb_uri_str;
+      gpr_asprintf(&lb_uri_str, "ipv4:127.0.0.1:%d", ports[i]);
+      grpc_uri* lb_uri = grpc_uri_parse(&exec_ctx, lb_uri_str, true);
+      GPR_ASSERT(lb_uri != NULL);
+      grpc_lb_addresses_set_address_from_uri(addresses, i, lb_uri,
+                                             false /* is balancer */,
+                                             "" /* balancer name */, NULL);
+      grpc_uri_destroy(lb_uri);
+      gpr_free(lb_uri_str);
+    }
+    const grpc_arg fake_addresses =
+        grpc_lb_addresses_create_channel_arg(addresses);
+    grpc_channel_args* fake_result =
+        grpc_channel_args_copy_and_add(NULL, &fake_addresses, 1);
+    grpc_fake_resolver_response_generator_set_response(
+        &exec_ctx, response_generator_, fake_result);
+    grpc_channel_args_destroy(&exec_ctx, fake_result);
+    grpc_lb_addresses_destroy(&exec_ctx, addresses);
+    grpc_exec_ctx_finish(&exec_ctx);
+  }
+
+  void ResetStub(const grpc::string& lb_policy_name = "") {
+    ChannelArguments args;
+    if (lb_policy_name.size() > 0) {
+      args.SetLoadBalancingPolicyName(lb_policy_name);
+    }  // else, default to pick first
+    args.SetPointer(GRPC_ARG_FAKE_RESOLVER_RESPONSE_GENERATOR,
+                    response_generator_);
+    std::ostringstream uri;
+    uri << "fake:///";
+    for (size_t i = 0; i < servers_.size() - 1; ++i) {
+      uri << "127.0.0.1:" << servers_[i]->port_ << ",";
+    }
+    uri << "127.0.0.1:" << servers_[servers_.size() - 1]->port_;
+    channel_ =
+        CreateCustomChannel(uri.str(), InsecureChannelCredentials(), args);
+    stub_ = grpc::testing::EchoTestService::NewStub(channel_);
+  }
+
+  void SendRpc() {
+    EchoRequest request;
+    EchoResponse response;
+    request.set_message("Live long and prosper.");
+    ClientContext context;
+    Status status = stub_->Echo(&context, request, &response);
+    EXPECT_TRUE(status.ok());
+    EXPECT_EQ(response.message(), request.message());
+  }
+
+  struct ServerData {
+    int port_;
+    std::unique_ptr<Server> server_;
+    MyTestServiceImpl service_;
+    std::unique_ptr<std::thread> thread_;
+
+    explicit ServerData(const grpc::string& server_host) {
+      port_ = grpc_pick_unused_port_or_die();
+      gpr_log(GPR_INFO, "starting server on port %d", port_);
+      std::mutex mu;
+      std::condition_variable cond;
+      thread_.reset(new std::thread(
+          std::bind(&ServerData::Start, this, server_host, &mu, &cond)));
+      std::unique_lock<std::mutex> lock(mu);
+      cond.wait(lock);
+      gpr_log(GPR_INFO, "server startup complete");
+    }
+
+    void Start(const grpc::string& server_host, std::mutex* mu,
+               std::condition_variable* cond) {
+      std::ostringstream server_address;
+      server_address << server_host << ":" << port_;
+      ServerBuilder builder;
+      builder.AddListeningPort(server_address.str(),
+                               InsecureServerCredentials());
+      builder.RegisterService(&service_);
+      server_ = builder.BuildAndStart();
+      std::lock_guard<std::mutex> lock(*mu);
+      cond->notify_one();
+    }
+
+    void Shutdown() {
+      server_->Shutdown();
+      thread_->join();
+    }
+  };
+
+  void ResetCounters() {
+    for (const auto& server : servers_) server->service_.ResetCounters();
+  }
+
+  void WaitForServer(size_t server_idx) {
+    do {
+      SendRpc();
+    } while (servers_[server_idx]->service_.request_count() == 0);
+    ResetCounters();
+  }
+
+  const grpc::string server_host_;
+  std::shared_ptr<Channel> channel_;
+  std::unique_ptr<grpc::testing::EchoTestService::Stub> stub_;
+  std::vector<std::unique_ptr<ServerData>> servers_;
+  grpc_fake_resolver_response_generator* response_generator_;
+};
+
+TEST_F(ClientLbEnd2endTest, PickFirst) {
+  // Start servers and send one RPC per server.
+  const int kNumServers = 3;
+  StartServers(kNumServers);
+  ResetStub();  // implicit pick first
+  std::vector<int> ports;
+  for (size_t i = 0; i < servers_.size(); ++i) {
+    ports.emplace_back(servers_[i]->port_);
+  }
+  SetNextResolution(ports);
+  for (size_t i = 0; i < servers_.size(); ++i) {
+    SendRpc();
+  }
+  // All requests should have gone to a single server.
+  bool found = false;
+  for (size_t i = 0; i < servers_.size(); ++i) {
+    const int request_count = servers_[i]->service_.request_count();
+    if (request_count == kNumServers) {
+      found = true;
+    } else {
+      EXPECT_EQ(0, request_count);
+    }
+  }
+  EXPECT_TRUE(found);
+  // Check LB policy name for the channel.
+  EXPECT_EQ("pick_first", channel_->GetLoadBalancingPolicyName());
+}
+
+TEST_F(ClientLbEnd2endTest, PickFirstUpdates) {
+  // Start servers and send one RPC per server.
+  const int kNumServers = 3;
+  StartServers(kNumServers);
+  ResetStub();  // implicit pick first
+  std::vector<int> ports;
+
+  // Perform one RPC against the first server.
+  ports.emplace_back(servers_[0]->port_);
+  SetNextResolution(ports);
+  gpr_log(GPR_INFO, "****** SET [0] *******");
+  SendRpc();
+  EXPECT_EQ(servers_[0]->service_.request_count(), 1);
+
+  // An empty update will result in the channel going into TRANSIENT_FAILURE.
+  ports.clear();
+  SetNextResolution(ports);
+  gpr_log(GPR_INFO, "****** SET none *******");
+  grpc_connectivity_state channel_state = GRPC_CHANNEL_INIT;
+  do {
+    channel_state = channel_->GetState(true /* try to connect */);
+  } while (channel_state == GRPC_CHANNEL_READY);
+  GPR_ASSERT(channel_state != GRPC_CHANNEL_READY);
+  servers_[0]->service_.ResetCounters();
+
+  // Next update introduces servers_[1], making the channel recover.
+  ports.clear();
+  ports.emplace_back(servers_[1]->port_);
+  SetNextResolution(ports);
+  gpr_log(GPR_INFO, "****** SET [1] *******");
+  WaitForServer(1);
+  EXPECT_EQ(servers_[0]->service_.request_count(), 0);
+
+  // And again for servers_[2]
+  ports.clear();
+  ports.emplace_back(servers_[2]->port_);
+  SetNextResolution(ports);
+  gpr_log(GPR_INFO, "****** SET [2] *******");
+  WaitForServer(2);
+  EXPECT_EQ(servers_[0]->service_.request_count(), 0);
+  EXPECT_EQ(servers_[1]->service_.request_count(), 0);
+
+  // Check LB policy name for the channel.
+  EXPECT_EQ("pick_first", channel_->GetLoadBalancingPolicyName());
+}
+
+TEST_F(ClientLbEnd2endTest, PickFirstUpdateSuperset) {
+  // Start servers and send one RPC per server.
+  const int kNumServers = 3;
+  StartServers(kNumServers);
+  ResetStub();  // implicit pick first
+  std::vector<int> ports;
+
+  // Perform one RPC against the first server.
+  ports.emplace_back(servers_[0]->port_);
+  SetNextResolution(ports);
+  gpr_log(GPR_INFO, "****** SET [0] *******");
+  SendRpc();
+  EXPECT_EQ(servers_[0]->service_.request_count(), 1);
+  servers_[0]->service_.ResetCounters();
+
+  // Send and superset update
+  ports.clear();
+  ports.emplace_back(servers_[1]->port_);
+  ports.emplace_back(servers_[0]->port_);
+  SetNextResolution(ports);
+  gpr_log(GPR_INFO, "****** SET superset *******");
+  SendRpc();
+  // We stick to the previously connected server.
+  WaitForServer(0);
+  EXPECT_EQ(0, servers_[1]->service_.request_count());
+
+  // Check LB policy name for the channel.
+  EXPECT_EQ("pick_first", channel_->GetLoadBalancingPolicyName());
+}
+
+TEST_F(ClientLbEnd2endTest, PickFirstManyUpdates) {
+  // Start servers and send one RPC per server.
+  const int kNumServers = 3;
+  StartServers(kNumServers);
+  ResetStub();  // implicit pick first
+  std::vector<int> ports;
+  for (size_t i = 0; i < servers_.size(); ++i) {
+    ports.emplace_back(servers_[i]->port_);
+  }
+  for (size_t i = 0; i < 1000; ++i) {
+    std::random_shuffle(ports.begin(), ports.end());
+    SetNextResolution(ports);
+    if (i % 10 == 0) SendRpc();
+  }
+  // Check LB policy name for the channel.
+  EXPECT_EQ("pick_first", channel_->GetLoadBalancingPolicyName());
+}
+
+TEST_F(ClientLbEnd2endTest, RoundRobin) {
+  // Start servers and send one RPC per server.
+  const int kNumServers = 3;
+  StartServers(kNumServers);
+  ResetStub("round_robin");
+  std::vector<int> ports;
+  for (const auto& server : servers_) {
+    ports.emplace_back(server->port_);
+  }
+  SetNextResolution(ports);
+  for (size_t i = 0; i < servers_.size(); ++i) {
+    SendRpc();
+  }
+  // One request should have gone to each server.
+  for (size_t i = 0; i < servers_.size(); ++i) {
+    EXPECT_EQ(1, servers_[i]->service_.request_count());
+  }
+  // Check LB policy name for the channel.
+  EXPECT_EQ("round_robin", channel_->GetLoadBalancingPolicyName());
+}
+
+TEST_F(ClientLbEnd2endTest, RoundRobinUpdates) {
+  // Start servers and send one RPC per server.
+  const int kNumServers = 3;
+  StartServers(kNumServers);
+  ResetStub("round_robin");
+  std::vector<int> ports;
+
+  // Start with a single server.
+  ports.emplace_back(servers_[0]->port_);
+  SetNextResolution(ports);
+  WaitForServer(0);
+  // Send RPCs. They should all go servers_[0]
+  for (size_t i = 0; i < 10; ++i) SendRpc();
+  EXPECT_EQ(10, servers_[0]->service_.request_count());
+  EXPECT_EQ(0, servers_[1]->service_.request_count());
+  EXPECT_EQ(0, servers_[2]->service_.request_count());
+  servers_[0]->service_.ResetCounters();
+
+  // And now for the second server.
+  ports.clear();
+  ports.emplace_back(servers_[1]->port_);
+  SetNextResolution(ports);
+
+  // Wait until update has been processed, as signaled by the second backend
+  // receiving a request.
+  EXPECT_EQ(0, servers_[1]->service_.request_count());
+  WaitForServer(1);
+
+  for (size_t i = 0; i < 10; ++i) SendRpc();
+  EXPECT_EQ(0, servers_[0]->service_.request_count());
+  EXPECT_EQ(10, servers_[1]->service_.request_count());
+  EXPECT_EQ(0, servers_[2]->service_.request_count());
+  servers_[1]->service_.ResetCounters();
+
+  // ... and for the last server.
+  ports.clear();
+  ports.emplace_back(servers_[2]->port_);
+  SetNextResolution(ports);
+  WaitForServer(2);
+
+  for (size_t i = 0; i < 10; ++i) SendRpc();
+  EXPECT_EQ(0, servers_[0]->service_.request_count());
+  EXPECT_EQ(0, servers_[1]->service_.request_count());
+  EXPECT_EQ(10, servers_[2]->service_.request_count());
+  servers_[2]->service_.ResetCounters();
+
+  // Back to all servers.
+  ports.clear();
+  ports.emplace_back(servers_[0]->port_);
+  ports.emplace_back(servers_[1]->port_);
+  ports.emplace_back(servers_[2]->port_);
+  SetNextResolution(ports);
+  WaitForServer(0);
+  WaitForServer(1);
+  WaitForServer(2);
+
+  // Send three RPCs, one per server.
+  for (size_t i = 0; i < 3; ++i) SendRpc();
+  EXPECT_EQ(1, servers_[0]->service_.request_count());
+  EXPECT_EQ(1, servers_[1]->service_.request_count());
+  EXPECT_EQ(1, servers_[2]->service_.request_count());
+
+  // An empty update will result in the channel going into TRANSIENT_FAILURE.
+  ports.clear();
+  SetNextResolution(ports);
+  grpc_connectivity_state channel_state = GRPC_CHANNEL_INIT;
+  do {
+    channel_state = channel_->GetState(true /* try to connect */);
+  } while (channel_state == GRPC_CHANNEL_READY);
+  GPR_ASSERT(channel_state != GRPC_CHANNEL_READY);
+  servers_[0]->service_.ResetCounters();
+
+  // Next update introduces servers_[1], making the channel recover.
+  ports.clear();
+  ports.emplace_back(servers_[1]->port_);
+  SetNextResolution(ports);
+  WaitForServer(1);
+  channel_state = channel_->GetState(false /* try to connect */);
+  GPR_ASSERT(channel_state == GRPC_CHANNEL_READY);
+
+  // Check LB policy name for the channel.
+  EXPECT_EQ("round_robin", channel_->GetLoadBalancingPolicyName());
+}
+
+TEST_F(ClientLbEnd2endTest, RoundRobinManyUpdates) {
+  // Start servers and send one RPC per server.
+  const int kNumServers = 3;
+  StartServers(kNumServers);
+  ResetStub("round_robin");
+  std::vector<int> ports;
+  for (size_t i = 0; i < servers_.size(); ++i) {
+    ports.emplace_back(servers_[i]->port_);
+  }
+  for (size_t i = 0; i < 1000; ++i) {
+    std::random_shuffle(ports.begin(), ports.end());
+    SetNextResolution(ports);
+    if (i % 10 == 0) SendRpc();
+  }
+  // Check LB policy name for the channel.
+  EXPECT_EQ("round_robin", channel_->GetLoadBalancingPolicyName());
+}
+
+}  // namespace
+}  // namespace testing
+}  // namespace grpc
+
+int main(int argc, char** argv) {
+  ::testing::InitGoogleTest(&argc, argv);
+  grpc_test_init(argc, argv);
+  grpc_init();
+  const auto result = RUN_ALL_TESTS();
+  grpc_shutdown();
+  return result;
+}
diff --git a/test/cpp/end2end/grpclb_end2end_test.cc b/test/cpp/end2end/grpclb_end2end_test.cc
index b0d4e2dadf..6ff3642adf 100644
--- a/test/cpp/end2end/grpclb_end2end_test.cc
+++ b/test/cpp/end2end/grpclb_end2end_test.cc
@@ -50,8 +50,8 @@
 #include <gtest/gtest.h>
 
 extern "C" {
+#include "src/core/ext/filters/client_channel/resolver/fake/fake_resolver.h"
 #include "src/core/lib/iomgr/sockaddr.h"
-#include "test/core/end2end/fake_resolver.h"
 }
 
 #include "test/core/util/port.h"
@@ -117,6 +117,12 @@ class CountedService : public ServiceType {
     ++request_count_;
   }
 
+  void ResetCounters() {
+    std::unique_lock<std::mutex> lock(mu_);
+    request_count_ = 0;
+    response_count_ = 0;
+  }
+
  protected:
   std::mutex mu_;
 
@@ -181,6 +187,7 @@ class BalancerServiceImpl : public BalancerService {
         shutdown_(false) {}
 
   Status BalanceLoad(ServerContext* context, Stream* stream) override {
+    gpr_log(GPR_INFO, "LB: BalanceLoad");
     LoadBalanceRequest request;
     stream->Read(&request);
     IncreaseRequestCount();
@@ -200,9 +207,16 @@ class BalancerServiceImpl : public BalancerService {
       responses_and_delays = responses_and_delays_;
     }
     for (const auto& response_and_delay : responses_and_delays) {
-      if (shutdown_) break;
+      {
+        std::unique_lock<std::mutex> lock(mu_);
+        if (shutdown_) break;
+      }
       SendResponse(stream, response_and_delay.first, response_and_delay.second);
     }
+    {
+      std::unique_lock<std::mutex> lock(mu_);
+      serverlist_cond_.wait(lock);
+    }
 
     if (client_load_reporting_interval_seconds_ > 0) {
       request.Clear();
@@ -226,9 +240,10 @@ class BalancerServiceImpl : public BalancerService {
       client_stats_.num_calls_finished_known_received +=
           request.client_stats().num_calls_finished_known_received();
       std::lock_guard<std::mutex> lock(mu_);
-      cond_.notify_one();
+      load_report_cond_.notify_one();
     }
 
+    gpr_log(GPR_INFO, "LB: done");
     return Status::OK;
   }
 
@@ -237,9 +252,14 @@ class BalancerServiceImpl : public BalancerService {
     responses_and_delays_.push_back(std::make_pair(response, send_after_ms));
   }
 
-  void Shutdown() {
+  // Returns true on its first invocation, false otherwise.
+  bool Shutdown() {
+    NotifyDoneWithServerlists();
     std::unique_lock<std::mutex> lock(mu_);
+    const bool prev = !shutdown_;
     shutdown_ = true;
+    gpr_log(GPR_INFO, "LB: shut down");
+    return prev;
   }
 
   static LoadBalanceResponse BuildResponseForBackends(
@@ -264,26 +284,35 @@ class BalancerServiceImpl : public BalancerService {
 
   const ClientStats& WaitForLoadReport() {
     std::unique_lock<std::mutex> lock(mu_);
-    cond_.wait(lock);
+    load_report_cond_.wait(lock);
     return client_stats_;
   }
 
+  void NotifyDoneWithServerlists() {
+    std::lock_guard<std::mutex> lock(mu_);
+    serverlist_cond_.notify_one();
+  }
+
  private:
   void SendResponse(Stream* stream, const LoadBalanceResponse& response,
                     int delay_ms) {
     gpr_log(GPR_INFO, "LB: sleeping for %d ms...", delay_ms);
-    gpr_sleep_until(gpr_time_add(gpr_now(GPR_CLOCK_REALTIME),
-                                 gpr_time_from_millis(delay_ms, GPR_TIMESPAN)));
+    if (delay_ms > 0) {
+      gpr_sleep_until(
+          gpr_time_add(gpr_now(GPR_CLOCK_REALTIME),
+                       gpr_time_from_millis(delay_ms, GPR_TIMESPAN)));
+    }
     gpr_log(GPR_INFO, "LB: Woke up! Sending response '%s'",
             response.DebugString().c_str());
-    stream->Write(response);
     IncreaseResponseCount();
+    stream->Write(response);
   }
 
   const int client_load_reporting_interval_seconds_;
   std::vector<ResponseDelayPair> responses_and_delays_;
   std::mutex mu_;
-  std::condition_variable cond_;
+  std::condition_variable load_report_cond_;
+  std::condition_variable serverlist_cond_;
   ClientStats client_stats_;
   bool shutdown_;
 };
@@ -326,8 +355,7 @@ class GrpclbEnd2endTest : public ::testing::Test {
       backend_servers_[i].Shutdown();
     }
     for (size_t i = 0; i < balancers_.size(); ++i) {
-      balancers_[i]->Shutdown();
-      balancer_servers_[i].Shutdown();
+      if (balancers_[i]->Shutdown()) balancer_servers_[i].Shutdown();
     }
     grpc_fake_resolver_response_generator_unref(response_generator_);
   }
@@ -336,8 +364,10 @@ class GrpclbEnd2endTest : public ::testing::Test {
     ChannelArguments args;
     args.SetPointer(GRPC_ARG_FAKE_RESOLVER_RESPONSE_GENERATOR,
                     response_generator_);
-    channel_ = CreateCustomChannel("test:///not_used",
-                                   InsecureChannelCredentials(), args);
+    std::ostringstream uri;
+    uri << "fake:///servername_not_used";
+    channel_ =
+        CreateCustomChannel(uri.str(), InsecureChannelCredentials(), args);
     stub_ = grpc::testing::EchoTestService::NewStub(channel_);
   }
 
@@ -497,6 +527,7 @@ TEST_F(SingleBalancerTest, Vanilla) {
     EXPECT_EQ(kNumRpcsPerAddress,
               backend_servers_[i].service_->request_count());
   }
+  balancers_[0]->NotifyDoneWithServerlists();
   // The balancer got a single request.
   EXPECT_EQ(1U, balancer_servers_[0].service_->request_count());
   // and sent a single response.
@@ -541,7 +572,7 @@ TEST_F(SingleBalancerTest, InitiallyEmptyServerlist) {
                              << " message=" << status.error_message();
     EXPECT_EQ(response.message(), kMessage_);
   }
-
+  balancers_[0]->NotifyDoneWithServerlists();
   // The balancer got a single request.
   EXPECT_EQ(1U, balancer_servers_[0].service_->request_count());
   // and sent two responses.
@@ -608,13 +639,272 @@ TEST_F(SingleBalancerTest, RepeatedServerlist) {
                              << " message=" << status.error_message();
     EXPECT_EQ(response.message(), kMessage_);
   }
-
+  balancers_[0]->NotifyDoneWithServerlists();
   // The balancer got a single request.
   EXPECT_EQ(1U, balancer_servers_[0].service_->request_count());
   // Check LB policy name for the channel.
   EXPECT_EQ("grpclb", channel_->GetLoadBalancingPolicyName());
 }
 
+class UpdatesTest : public GrpclbEnd2endTest {
+ public:
+  UpdatesTest() : GrpclbEnd2endTest(4, 3, 0) {}
+};
+
+TEST_F(UpdatesTest, UpdateBalancers) {
+  const std::vector<int> first_backend{GetBackendPorts()[0]};
+  const std::vector<int> second_backend{GetBackendPorts()[1]};
+
+  ScheduleResponseForBalancer(
+      0, BalancerServiceImpl::BuildResponseForBackends(first_backend, 0, 0), 0);
+  ScheduleResponseForBalancer(
+      1, BalancerServiceImpl::BuildResponseForBackends(second_backend, 0, 0),
+      0);
+
+  // Start servers and send 10 RPCs per server.
+  gpr_log(GPR_INFO, "========= BEFORE FIRST BATCH ==========");
+  auto statuses_and_responses = SendRpc(kMessage_, 10);
+  gpr_log(GPR_INFO, "========= DONE WITH FIRST BATCH ==========");
+
+  for (const auto& status_and_response : statuses_and_responses) {
+    EXPECT_TRUE(status_and_response.first.ok());
+    EXPECT_EQ(status_and_response.second.message(), kMessage_);
+  }
+  // All 10 requests should have gone to the first backend.
+  EXPECT_EQ(10U, backend_servers_[0].service_->request_count());
+
+  balancers_[0]->NotifyDoneWithServerlists();
+  balancers_[1]->NotifyDoneWithServerlists();
+  balancers_[2]->NotifyDoneWithServerlists();
+  // Balancer 0 got a single request.
+  EXPECT_EQ(1U, balancer_servers_[0].service_->request_count());
+  // and sent a single response.
+  EXPECT_EQ(1U, balancer_servers_[0].service_->response_count());
+  EXPECT_EQ(0U, balancer_servers_[1].service_->request_count());
+  EXPECT_EQ(0U, balancer_servers_[1].service_->response_count());
+  EXPECT_EQ(0U, balancer_servers_[2].service_->request_count());
+  EXPECT_EQ(0U, balancer_servers_[2].service_->response_count());
+
+  std::vector<AddressData> addresses;
+  addresses.emplace_back(AddressData{balancer_servers_[1].port_, true, ""});
+  gpr_log(GPR_INFO, "========= ABOUT TO UPDATE 1 ==========");
+  SetNextResolution(addresses);
+  gpr_log(GPR_INFO, "========= UPDATE 1 DONE ==========");
+
+  // Wait until update has been processed, as signaled by the second backend
+  // receiving a request.
+  EXPECT_EQ(0U, backend_servers_[1].service_->request_count());
+  do {
+    auto statuses_and_responses = SendRpc(kMessage_, 1);
+    for (const auto& status_and_response : statuses_and_responses) {
+      EXPECT_TRUE(status_and_response.first.ok());
+      EXPECT_EQ(status_and_response.second.message(), kMessage_);
+    }
+  } while (backend_servers_[1].service_->request_count() == 0);
+
+  backend_servers_[1].service_->ResetCounters();
+  gpr_log(GPR_INFO, "========= BEFORE SECOND BATCH ==========");
+  statuses_and_responses = SendRpc(kMessage_, 10);
+  gpr_log(GPR_INFO, "========= DONE WITH SECOND BATCH ==========");
+  for (const auto& status_and_response : statuses_and_responses) {
+    EXPECT_TRUE(status_and_response.first.ok());
+    EXPECT_EQ(status_and_response.second.message(), kMessage_);
+  }
+  // All 10 requests should have gone to the second backend.
+  EXPECT_EQ(10U, backend_servers_[1].service_->request_count());
+
+  balancers_[0]->NotifyDoneWithServerlists();
+  balancers_[1]->NotifyDoneWithServerlists();
+  balancers_[2]->NotifyDoneWithServerlists();
+  EXPECT_EQ(1U, balancer_servers_[0].service_->request_count());
+  EXPECT_EQ(1U, balancer_servers_[0].service_->response_count());
+  EXPECT_EQ(1U, balancer_servers_[1].service_->request_count());
+  EXPECT_EQ(1U, balancer_servers_[1].service_->response_count());
+  EXPECT_EQ(0U, balancer_servers_[2].service_->request_count());
+  EXPECT_EQ(0U, balancer_servers_[2].service_->response_count());
+  // Check LB policy name for the channel.
+  EXPECT_EQ("grpclb", channel_->GetLoadBalancingPolicyName());
+}
+
+// Send an update with the same set of LBs as the one in SetUp() in order to
+// verify that the LB channel inside grpclb keeps the initial connection (which
+// by definition is also present in the update).
+TEST_F(UpdatesTest, UpdateBalancersRepeated) {
+  const std::vector<int> first_backend{GetBackendPorts()[0]};
+  const std::vector<int> second_backend{GetBackendPorts()[0]};
+
+  ScheduleResponseForBalancer(
+      0, BalancerServiceImpl::BuildResponseForBackends(first_backend, 0, 0), 0);
+  ScheduleResponseForBalancer(
+      1, BalancerServiceImpl::BuildResponseForBackends(second_backend, 0, 0),
+      0);
+
+  // Start servers and send 10 RPCs per server.
+  gpr_log(GPR_INFO, "========= BEFORE FIRST BATCH ==========");
+  auto statuses_and_responses = SendRpc(kMessage_, 10);
+  gpr_log(GPR_INFO, "========= DONE WITH FIRST BATCH ==========");
+
+  for (const auto& status_and_response : statuses_and_responses) {
+    EXPECT_TRUE(status_and_response.first.ok());
+    EXPECT_EQ(status_and_response.second.message(), kMessage_);
+  }
+  // All 10 requests should have gone to the first backend.
+  EXPECT_EQ(10U, backend_servers_[0].service_->request_count());
+
+  balancers_[0]->NotifyDoneWithServerlists();
+  // Balancer 0 got a single request.
+  EXPECT_EQ(1U, balancer_servers_[0].service_->request_count());
+  // and sent a single response.
+  EXPECT_EQ(1U, balancer_servers_[0].service_->response_count());
+  EXPECT_EQ(0U, balancer_servers_[1].service_->request_count());
+  EXPECT_EQ(0U, balancer_servers_[1].service_->response_count());
+  EXPECT_EQ(0U, balancer_servers_[2].service_->request_count());
+  EXPECT_EQ(0U, balancer_servers_[2].service_->response_count());
+
+  std::vector<AddressData> addresses;
+  addresses.emplace_back(AddressData{balancer_servers_[0].port_, true, ""});
+  addresses.emplace_back(AddressData{balancer_servers_[1].port_, true, ""});
+  addresses.emplace_back(AddressData{balancer_servers_[2].port_, true, ""});
+  gpr_log(GPR_INFO, "========= ABOUT TO UPDATE 1 ==========");
+  SetNextResolution(addresses);
+  gpr_log(GPR_INFO, "========= UPDATE 1 DONE ==========");
+
+  EXPECT_EQ(0U, backend_servers_[1].service_->request_count());
+  gpr_timespec deadline = gpr_time_add(
+      gpr_now(GPR_CLOCK_REALTIME), gpr_time_from_millis(10000, GPR_TIMESPAN));
+  // Send 10 seconds worth of RPCs
+  do {
+    statuses_and_responses = SendRpc(kMessage_, 1);
+    for (const auto& status_and_response : statuses_and_responses) {
+      EXPECT_TRUE(status_and_response.first.ok());
+      EXPECT_EQ(status_and_response.second.message(), kMessage_);
+    }
+  } while (gpr_time_cmp(gpr_now(GPR_CLOCK_REALTIME), deadline) < 0);
+  // grpclb continued using the original LB call to the first balancer, which
+  // doesn't assign the second backend.
+  EXPECT_EQ(0U, backend_servers_[1].service_->request_count());
+  balancers_[0]->NotifyDoneWithServerlists();
+
+  addresses.clear();
+  addresses.emplace_back(AddressData{balancer_servers_[0].port_, true, ""});
+  addresses.emplace_back(AddressData{balancer_servers_[1].port_, true, ""});
+  gpr_log(GPR_INFO, "========= ABOUT TO UPDATE 2 ==========");
+  SetNextResolution(addresses);
+  gpr_log(GPR_INFO, "========= UPDATE 2 DONE ==========");
+
+  EXPECT_EQ(0U, backend_servers_[1].service_->request_count());
+  deadline = gpr_time_add(gpr_now(GPR_CLOCK_REALTIME),
+                          gpr_time_from_millis(10000, GPR_TIMESPAN));
+  // Send 10 seconds worth of RPCs
+  do {
+    statuses_and_responses = SendRpc(kMessage_, 1);
+    for (const auto& status_and_response : statuses_and_responses) {
+      EXPECT_TRUE(status_and_response.first.ok());
+      EXPECT_EQ(status_and_response.second.message(), kMessage_);
+    }
+  } while (gpr_time_cmp(gpr_now(GPR_CLOCK_REALTIME), deadline) < 0);
+  // grpclb continued using the original LB call to the first balancer, which
+  // doesn't assign the second backend.
+  EXPECT_EQ(0U, backend_servers_[1].service_->request_count());
+  balancers_[0]->NotifyDoneWithServerlists();
+
+  // Check LB policy name for the channel.
+  EXPECT_EQ("grpclb", channel_->GetLoadBalancingPolicyName());
+}
+
+TEST_F(UpdatesTest, UpdateBalancersDeadUpdate) {
+  const std::vector<int> first_backend{GetBackendPorts()[0]};
+  const std::vector<int> second_backend{GetBackendPorts()[1]};
+
+  ScheduleResponseForBalancer(
+      0, BalancerServiceImpl::BuildResponseForBackends(first_backend, 0, 0), 0);
+  ScheduleResponseForBalancer(
+      1, BalancerServiceImpl::BuildResponseForBackends(second_backend, 0, 0),
+      0);
+
+  // Start servers and send 10 RPCs per server.
+  gpr_log(GPR_INFO, "========= BEFORE FIRST BATCH ==========");
+  auto statuses_and_responses = SendRpc(kMessage_, 10);
+  gpr_log(GPR_INFO, "========= DONE WITH FIRST BATCH ==========");
+  for (const auto& status_and_response : statuses_and_responses) {
+    EXPECT_TRUE(status_and_response.first.ok());
+    EXPECT_EQ(status_and_response.second.message(), kMessage_);
+  }
+  // All 10 requests should have gone to the first backend.
+  EXPECT_EQ(10U, backend_servers_[0].service_->request_count());
+
+  // Kill balancer 0
+  gpr_log(GPR_INFO, "********** ABOUT TO KILL BALANCER 0 *************");
+  if (balancers_[0]->Shutdown()) balancer_servers_[0].Shutdown();
+  gpr_log(GPR_INFO, "********** KILLED BALANCER 0 *************");
+
+  // This is serviced by the existing RR policy
+  gpr_log(GPR_INFO, "========= BEFORE SECOND BATCH ==========");
+  statuses_and_responses = SendRpc(kMessage_, 10);
+  gpr_log(GPR_INFO, "========= DONE WITH SECOND BATCH ==========");
+  for (const auto& status_and_response : statuses_and_responses) {
+    EXPECT_TRUE(status_and_response.first.ok());
+    EXPECT_EQ(status_and_response.second.message(), kMessage_);
+  }
+  // All 10 requests should again have gone to the first backend.
+  EXPECT_EQ(20U, backend_servers_[0].service_->request_count());
+  EXPECT_EQ(0U, backend_servers_[1].service_->request_count());
+
+  balancers_[0]->NotifyDoneWithServerlists();
+  balancers_[1]->NotifyDoneWithServerlists();
+  balancers_[2]->NotifyDoneWithServerlists();
+  // Balancer 0 got a single request.
+  EXPECT_EQ(1U, balancer_servers_[0].service_->request_count());
+  // and sent a single response.
+  EXPECT_EQ(1U, balancer_servers_[0].service_->response_count());
+  EXPECT_EQ(0U, balancer_servers_[1].service_->request_count());
+  EXPECT_EQ(0U, balancer_servers_[1].service_->response_count());
+  EXPECT_EQ(0U, balancer_servers_[2].service_->request_count());
+  EXPECT_EQ(0U, balancer_servers_[2].service_->response_count());
+
+  std::vector<AddressData> addresses;
+  addresses.emplace_back(AddressData{balancer_servers_[1].port_, true, ""});
+  gpr_log(GPR_INFO, "========= ABOUT TO UPDATE 1 ==========");
+  SetNextResolution(addresses);
+  gpr_log(GPR_INFO, "========= UPDATE 1 DONE ==========");
+
+  // Wait until update has been processed, as signaled by the second backend
+  // receiving a request. In the meantime, the client continues to be serviced
+  // (by the first backend) without interruption.
+  EXPECT_EQ(0U, backend_servers_[1].service_->request_count());
+  do {
+    auto statuses_and_responses = SendRpc(kMessage_, 1);
+    for (const auto& status_and_response : statuses_and_responses) {
+      EXPECT_TRUE(status_and_response.first.ok());
+      EXPECT_EQ(status_and_response.second.message(), kMessage_);
+    }
+  } while (backend_servers_[1].service_->request_count() == 0);
+
+  // This is serviced by the existing RR policy
+  backend_servers_[1].service_->ResetCounters();
+  gpr_log(GPR_INFO, "========= BEFORE THIRD BATCH ==========");
+  statuses_and_responses = SendRpc(kMessage_, 10);
+  gpr_log(GPR_INFO, "========= DONE WITH THIRD BATCH ==========");
+  for (const auto& status_and_response : statuses_and_responses) {
+    EXPECT_TRUE(status_and_response.first.ok());
+    EXPECT_EQ(status_and_response.second.message(), kMessage_);
+  }
+  // All 10 requests should have gone to the second backend.
+  EXPECT_EQ(10U, backend_servers_[1].service_->request_count());
+
+  balancers_[0]->NotifyDoneWithServerlists();
+  balancers_[1]->NotifyDoneWithServerlists();
+  balancers_[2]->NotifyDoneWithServerlists();
+  EXPECT_EQ(1U, balancer_servers_[0].service_->request_count());
+  EXPECT_EQ(1U, balancer_servers_[0].service_->response_count());
+  EXPECT_EQ(1U, balancer_servers_[1].service_->request_count());
+  EXPECT_EQ(1U, balancer_servers_[1].service_->response_count());
+  EXPECT_EQ(0U, balancer_servers_[2].service_->request_count());
+  EXPECT_EQ(0U, balancer_servers_[2].service_->response_count());
+  // Check LB policy name for the channel.
+  EXPECT_EQ("grpclb", channel_->GetLoadBalancingPolicyName());
+}
+
 TEST_F(SingleBalancerTest, Drop) {
   const size_t kNumRpcsPerAddress = 100;
   ScheduleResponseForBalancer(
@@ -677,6 +967,7 @@ TEST_F(SingleBalancerWithClientLoadReportingTest, Vanilla) {
     EXPECT_EQ(kNumRpcsPerAddress,
               backend_servers_[i].service_->request_count());
   }
+  balancers_[0]->NotifyDoneWithServerlists();
   // The balancer got a single request.
   EXPECT_EQ(1U, balancer_servers_[0].service_->request_count());
   // and sent a single response.
@@ -722,6 +1013,7 @@ TEST_F(SingleBalancerWithClientLoadReportingTest, Drop) {
     EXPECT_EQ(kNumRpcsPerAddress,
               backend_servers_[i].service_->request_count());
   }
+  balancers_[0]->NotifyDoneWithServerlists();
   // The balancer got a single request.
   EXPECT_EQ(1U, balancer_servers_[0].service_->request_count());
   // and sent a single response.
@@ -748,7 +1040,6 @@ TEST_F(SingleBalancerWithClientLoadReportingTest, Drop) {
 int main(int argc, char** argv) {
   grpc_init();
   grpc_test_init(argc, argv);
-  grpc_fake_resolver_init();
   ::testing::InitGoogleTest(&argc, argv);
   const auto result = RUN_ALL_TESTS();
   grpc_shutdown();
diff --git a/test/cpp/grpclb/grpclb_test.cc b/test/cpp/grpclb/grpclb_test.cc
index a002c7f77d..ee5dfa7133 100644
--- a/test/cpp/grpclb/grpclb_test.cc
+++ b/test/cpp/grpclb/grpclb_test.cc
@@ -52,6 +52,7 @@
 #include <grpc++/impl/codegen/config.h>
 extern "C" {
 #include "src/core/ext/filters/client_channel/client_channel.h"
+#include "src/core/ext/filters/client_channel/resolver/fake/fake_resolver.h"
 #include "src/core/lib/channel/channel_args.h"
 #include "src/core/lib/channel/channel_stack.h"
 #include "src/core/lib/iomgr/sockaddr.h"
@@ -61,7 +62,6 @@ extern "C" {
 #include "src/core/lib/surface/channel.h"
 #include "src/core/lib/surface/server.h"
 #include "test/core/end2end/cq_verifier.h"
-#include "test/core/end2end/fake_resolver.h"
 #include "test/core/util/port.h"
 #include "test/core/util/test_config.h"
 }
@@ -591,7 +591,7 @@ static void setup_client(const server_fixture *lb_server,
   grpc_uri_destroy(lb_uri);
   gpr_free(lb_uri_str);
 
-  gpr_asprintf(&cf->server_uri, "test:///%s", lb_server->servers_hostport);
+  gpr_asprintf(&cf->server_uri, "fake:///%s", lb_server->servers_hostport);
   const grpc_arg fake_addresses =
       grpc_lb_addresses_create_channel_arg(addresses);
   grpc_channel_args *fake_result =
@@ -804,7 +804,6 @@ TEST(GrpclbTest, InvalidAddressInServerlist) {}
 
 int main(int argc, char **argv) {
   ::testing::InitGoogleTest(&argc, argv);
-  grpc_fake_resolver_init();
   grpc_test_init(argc, argv);
   grpc_init();
   const auto result = RUN_ALL_TESTS();