Merge master

10 files changed, 95 insertions, 838 deletions

diff --git a/test/core/iomgr/BUILD b/test/core/iomgr/BUILD
index 675d9e6278..70ee83acd2 100644
--- a/test/core/iomgr/BUILD
+++ b/test/core/iomgr/BUILD
@@ -40,6 +40,7 @@ grpc_cc_library(
 grpc_cc_test(
     name = "combiner_test",
     srcs = ["combiner_test.cc"],
+    data = ["//third_party/toolchains:RBE_USE_MACHINE_TYPE_LARGE"],
     language = "C++",
     deps = [
         "//:gpr",
@@ -47,7 +48,6 @@ grpc_cc_test(
         "//test/core/util:gpr_test_util",
         "//test/core/util:grpc_test_util",
     ],
-    data = ["//third_party/toolchains:RBE_USE_MACHINE_TYPE_LARGE"],
 )
 
 grpc_cc_test(
@@ -89,18 +89,6 @@ grpc_cc_test(
 )
 
 grpc_cc_test(
-    name = "ev_epollsig_linux_test",
-    srcs = ["ev_epollsig_linux_test.cc"],
-    language = "C++",
-    deps = [
-        "//:gpr",
-        "//:grpc",
-        "//test/core/util:gpr_test_util",
-        "//test/core/util:grpc_test_util",
-    ],
-)
-
-grpc_cc_test(
     name = "fd_conservation_posix_test",
     srcs = ["fd_conservation_posix_test.cc"],
     language = "C++",
@@ -136,7 +124,6 @@ grpc_cc_test(
     ],
 )
 
-
 grpc_cc_test(
     name = "load_file_test",
     srcs = ["load_file_test.cc"],
@@ -150,8 +137,8 @@ grpc_cc_test(
 )
 
 grpc_cc_test(
-    name = "pollset_set_test",
-    srcs = ["pollset_set_test.cc"],
+    name = "resolve_address_posix_test",
+    srcs = ["resolve_address_posix_test.cc"],
     language = "C++",
     deps = [
         "//:gpr",
@@ -162,8 +149,11 @@ grpc_cc_test(
 )
 
 grpc_cc_test(
-    name = "resolve_address_posix_test",
-    srcs = ["resolve_address_posix_test.cc"],
+    name = "resolve_address_using_ares_resolver_test",
+    srcs = ["resolve_address_test.cc"],
+    args = [
+        "--resolver=ares",
+    ],
     language = "C++",
     deps = [
         "//:gpr",
@@ -174,8 +164,11 @@ grpc_cc_test(
 )
 
 grpc_cc_test(
-    name = "resolve_address_test",
+    name = "resolve_address_using_native_resolver_test",
     srcs = ["resolve_address_test.cc"],
+    args = [
+        "--resolver=native",
+    ],
     language = "C++",
     deps = [
         "//:gpr",
@@ -258,7 +251,6 @@ grpc_cc_test(
     ],
 )
 
-
 grpc_cc_test(
     name = "tcp_server_posix_test",
     srcs = ["tcp_server_posix_test.cc"],
diff --git a/test/core/iomgr/buffer_list_test.cc b/test/core/iomgr/buffer_list_test.cc
index 1086e42fcc..e104e8e91a 100644
--- a/test/core/iomgr/buffer_list_test.cc
+++ b/test/core/iomgr/buffer_list_test.cc
@@ -75,8 +75,8 @@ static void TestVerifierCalledOnAckVerifier(void* arg,
 static void TestVerifierCalledOnAck() {
   struct sock_extended_err serr;
   serr.ee_data = 213;
-  serr.ee_info = SCM_TSTAMP_ACK;
-  struct scm_timestamping tss;
+  serr.ee_info = grpc_core::SCM_TSTAMP_ACK;
+  struct grpc_core::scm_timestamping tss;
   tss.ts[0].tv_sec = 123;
   tss.ts[0].tv_nsec = 456;
   grpc_core::grpc_tcp_set_write_timestamps_callback(
diff --git a/test/core/iomgr/error_test.cc b/test/core/iomgr/error_test.cc
index a1628a1f71..d78a8c2af3 100644
--- a/test/core/iomgr/error_test.cc
+++ b/test/core/iomgr/error_test.cc
@@ -187,16 +187,6 @@ static void test_os_error() {
   GRPC_ERROR_UNREF(error);
 }
 
-static void test_special() {
-  grpc_error* error = GRPC_ERROR_NONE;
-  error = grpc_error_add_child(
-      error, GRPC_ERROR_CREATE_FROM_STATIC_STRING("test child"));
-  intptr_t i;
-  GPR_ASSERT(grpc_error_get_int(error, GRPC_ERROR_INT_GRPC_STATUS, &i));
-  GPR_ASSERT(i == GRPC_STATUS_OK);
-  GRPC_ERROR_UNREF(error);
-}
-
 static void test_overflow() {
   grpc_error* error = GRPC_ERROR_CREATE_FROM_STATIC_STRING("Overflow");
 
@@ -235,7 +225,6 @@ int main(int argc, char** argv) {
   test_os_error();
   test_create_referencing();
   test_create_referencing_many();
-  test_special();
   test_overflow();
   grpc_shutdown();
 
diff --git a/test/core/iomgr/ev_epollsig_linux_test.cc b/test/core/iomgr/ev_epollsig_linux_test.cc
deleted file mode 100644
index 28c9dd408c..0000000000
--- a/test/core/iomgr/ev_epollsig_linux_test.cc
+++ /dev/null
@@ -1,321 +0,0 @@
-/*
- *
- * Copyright 2015 gRPC authors.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- *
- */
-#include "src/core/lib/iomgr/port.h"
-
-/* This test only relevant on linux systems where epoll() is available */
-#ifdef GRPC_LINUX_EPOLL_CREATE1
-#include "src/core/lib/iomgr/ev_epollsig_linux.h"
-#include "src/core/lib/iomgr/ev_posix.h"
-
-#include <errno.h>
-#include <string.h>
-#include <unistd.h>
-
-#include <grpc/grpc.h>
-#include <grpc/support/alloc.h>
-#include <grpc/support/log.h>
-
-#include "src/core/lib/gpr/useful.h"
-#include "src/core/lib/gprpp/thd.h"
-#include "src/core/lib/iomgr/iomgr.h"
-#include "test/core/util/test_config.h"
-
-typedef struct test_pollset {
-  grpc_pollset* pollset;
-  gpr_mu* mu;
-} test_pollset;
-
-typedef struct test_fd {
-  int inner_fd;
-  grpc_fd* fd;
-} test_fd;
-
-/* num_fds should be an even number */
-static void test_fd_init(test_fd* tfds, int* fds, int num_fds) {
-  int i;
-  int r;
-
-  /* Create some dummy file descriptors. Currently using pipe file descriptors
-   * for this test but we could use any other type of file descriptors. Also,
-   * since pipe() used in this test creates two fds in each call, num_fds should
-   * be an even number */
-  GPR_ASSERT((num_fds % 2) == 0);
-  for (i = 0; i < num_fds; i = i + 2) {
-    r = pipe(fds + i);
-    if (r != 0) {
-      gpr_log(GPR_ERROR, "Error in creating pipe. %d (%s)", errno,
-              strerror(errno));
-      return;
-    }
-  }
-
-  for (i = 0; i < num_fds; i++) {
-    tfds[i].inner_fd = fds[i];
-    tfds[i].fd = grpc_fd_create(fds[i], "test_fd", false);
-  }
-}
-
-static void test_fd_cleanup(test_fd* tfds, int num_fds) {
-  int release_fd;
-  int i;
-
-  for (i = 0; i < num_fds; i++) {
-    grpc_fd_shutdown(tfds[i].fd,
-                     GRPC_ERROR_CREATE_FROM_STATIC_STRING("test_fd_cleanup"));
-    grpc_core::ExecCtx::Get()->Flush();
-
-    grpc_fd_orphan(tfds[i].fd, nullptr, &release_fd, "test_fd_cleanup");
-    grpc_core::ExecCtx::Get()->Flush();
-
-    GPR_ASSERT(release_fd == tfds[i].inner_fd);
-    close(tfds[i].inner_fd);
-  }
-}
-
-static void test_pollset_init(test_pollset* pollsets, int num_pollsets) {
-  int i;
-  for (i = 0; i < num_pollsets; i++) {
-    pollsets[i].pollset =
-        static_cast<grpc_pollset*>(gpr_zalloc(grpc_pollset_size()));
-    grpc_pollset_init(pollsets[i].pollset, &pollsets[i].mu);
-  }
-}
-
-static void destroy_pollset(void* p, grpc_error* error) {
-  grpc_pollset_destroy(static_cast<grpc_pollset*>(p));
-}
-
-static void test_pollset_cleanup(test_pollset* pollsets, int num_pollsets) {
-  grpc_closure destroyed;
-  int i;
-
-  for (i = 0; i < num_pollsets; i++) {
-    GRPC_CLOSURE_INIT(&destroyed, destroy_pollset, pollsets[i].pollset,
-                      grpc_schedule_on_exec_ctx);
-    grpc_pollset_shutdown(pollsets[i].pollset, &destroyed);
-
-    grpc_core::ExecCtx::Get()->Flush();
-    gpr_free(pollsets[i].pollset);
-  }
-}
-
-  /*
-   * Cases to test:
-   *  case 1) Polling islands of both fd and pollset are NULL
-   *  case 2) Polling island of fd is NULL but that of pollset is not-NULL
-   *  case 3) Polling island of fd is not-NULL but that of pollset is NULL
-   *  case 4) Polling islands of both fd and pollset are not-NULL and:
-   *     case 4.1) Polling islands of fd and pollset are equal
-   *     case 4.2) Polling islands of fd and pollset are NOT-equal (This results
-   *     in a merge)
-   * */
-
-#define NUM_FDS 8
-#define NUM_POLLSETS 4
-
-static void test_add_fd_to_pollset() {
-  grpc_core::ExecCtx exec_ctx;
-  test_fd tfds[NUM_FDS];
-  int fds[NUM_FDS];
-  test_pollset pollsets[NUM_POLLSETS];
-  void* expected_pi = nullptr;
-  int i;
-
-  test_fd_init(tfds, fds, NUM_FDS);
-  test_pollset_init(pollsets, NUM_POLLSETS);
-
-  /*Step 1.
-   * Create three polling islands (This will exercise test case 1 and 2) with
-   * the following configuration:
-   *   polling island 0 = { fds:0,1,2, pollsets:0}
-   *   polling island 1 = { fds:3,4,   pollsets:1}
-   *   polling island 2 = { fds:5,6,7  pollsets:2}
-   *
-   *Step 2.
-   * Add pollset 3 to polling island 0 (by adding fds 0 and 1 to pollset 3)
-   * (This will exercise test cases 3 and 4.1). The configuration becomes:
-   *   polling island 0 = { fds:0,1,2, pollsets:0,3} <<< pollset 3 added here
-   *   polling island 1 = { fds:3,4,   pollsets:1}
-   *   polling island 2 = { fds:5,6,7  pollsets:2}
-   *
-   *Step 3.
-   * Merge polling islands 0 and 1 by adding fd 0 to pollset 1 (This will
-   * exercise test case 4.2). The configuration becomes:
-   *   polling island (merged) = {fds: 0,1,2,3,4, pollsets: 0,1,3}
-   *   polling island 2 = {fds: 5,6,7 pollsets: 2}
-   *
-   *Step 4.
-   * Finally do one more merge by adding fd 3 to pollset 2.
-   *   polling island (merged) = {fds: 0,1,2,3,4,5,6,7, pollsets: 0,1,2,3}
-   */
-
-  /* == Step 1 == */
-  for (i = 0; i <= 2; i++) {
-    grpc_pollset_add_fd(pollsets[0].pollset, tfds[i].fd);
-    grpc_core::ExecCtx::Get()->Flush();
-  }
-
-  for (i = 3; i <= 4; i++) {
-    grpc_pollset_add_fd(pollsets[1].pollset, tfds[i].fd);
-    grpc_core::ExecCtx::Get()->Flush();
-  }
-
-  for (i = 5; i <= 7; i++) {
-    grpc_pollset_add_fd(pollsets[2].pollset, tfds[i].fd);
-    grpc_core::ExecCtx::Get()->Flush();
-  }
-
-  /* == Step 2 == */
-  for (i = 0; i <= 1; i++) {
-    grpc_pollset_add_fd(pollsets[3].pollset, tfds[i].fd);
-    grpc_core::ExecCtx::Get()->Flush();
-  }
-
-  /* == Step 3 == */
-  grpc_pollset_add_fd(pollsets[1].pollset, tfds[0].fd);
-  grpc_core::ExecCtx::Get()->Flush();
-
-  /* == Step 4 == */
-  grpc_pollset_add_fd(pollsets[2].pollset, tfds[3].fd);
-  grpc_core::ExecCtx::Get()->Flush();
-
-  /* All polling islands are merged at this point */
-
-  /* Compare Fd:0's polling island with that of all other Fds */
-  expected_pi = grpc_fd_get_polling_island(tfds[0].fd);
-  for (i = 1; i < NUM_FDS; i++) {
-    GPR_ASSERT(grpc_are_polling_islands_equal(
-        expected_pi, grpc_fd_get_polling_island(tfds[i].fd)));
-  }
-
-  /* Compare Fd:0's polling island with that of all other pollsets */
-  for (i = 0; i < NUM_POLLSETS; i++) {
-    GPR_ASSERT(grpc_are_polling_islands_equal(
-        expected_pi, grpc_pollset_get_polling_island(pollsets[i].pollset)));
-  }
-
-  test_fd_cleanup(tfds, NUM_FDS);
-  test_pollset_cleanup(pollsets, NUM_POLLSETS);
-}
-
-#undef NUM_FDS
-#undef NUM_POLLSETS
-
-typedef struct threading_shared {
-  gpr_mu* mu;
-  grpc_pollset* pollset;
-  grpc_wakeup_fd* wakeup_fd;
-  grpc_fd* wakeup_desc;
-  grpc_closure on_wakeup;
-  int wakeups;
-} threading_shared;
-
-static __thread int thread_wakeups = 0;
-
-static void test_threading_loop(void* arg) {
-  threading_shared* shared = static_cast<threading_shared*>(arg);
-  while (thread_wakeups < 1000000) {
-    grpc_core::ExecCtx exec_ctx;
-    grpc_pollset_worker* worker;
-    gpr_mu_lock(shared->mu);
-    GPR_ASSERT(GRPC_LOG_IF_ERROR(
-        "pollset_work",
-        grpc_pollset_work(shared->pollset, &worker, GRPC_MILLIS_INF_FUTURE)));
-    gpr_mu_unlock(shared->mu);
-  }
-}
-
-static void test_threading_wakeup(void* arg, grpc_error* error) {
-  threading_shared* shared = static_cast<threading_shared*>(arg);
-  ++shared->wakeups;
-  ++thread_wakeups;
-  if (error == GRPC_ERROR_NONE) {
-    GPR_ASSERT(GRPC_LOG_IF_ERROR(
-        "consume_wakeup", grpc_wakeup_fd_consume_wakeup(shared->wakeup_fd)));
-    grpc_fd_notify_on_read(shared->wakeup_desc, &shared->on_wakeup);
-    GPR_ASSERT(GRPC_LOG_IF_ERROR("wakeup_next",
-                                 grpc_wakeup_fd_wakeup(shared->wakeup_fd)));
-  }
-}
-
-static void test_threading(void) {
-  threading_shared shared;
-  shared.pollset = static_cast<grpc_pollset*>(gpr_zalloc(grpc_pollset_size()));
-  grpc_pollset_init(shared.pollset, &shared.mu);
-
-  grpc_core::Thread thds[10];
-  for (auto& th : thds) {
-    th = grpc_core::Thread("test_thread", test_threading_loop, &shared);
-    th.Start();
-  }
-  grpc_wakeup_fd fd;
-  GPR_ASSERT(GRPC_LOG_IF_ERROR("wakeup_fd_init", grpc_wakeup_fd_init(&fd)));
-  shared.wakeup_fd = &fd;
-  shared.wakeup_desc = grpc_fd_create(fd.read_fd, "wakeup", false);
-  shared.wakeups = 0;
-  {
-    grpc_core::ExecCtx exec_ctx;
-    grpc_pollset_add_fd(shared.pollset, shared.wakeup_desc);
-    grpc_fd_notify_on_read(
-        shared.wakeup_desc,
-        GRPC_CLOSURE_INIT(&shared.on_wakeup, test_threading_wakeup, &shared,
-                          grpc_schedule_on_exec_ctx));
-  }
-  GPR_ASSERT(GRPC_LOG_IF_ERROR("wakeup_first",
-                               grpc_wakeup_fd_wakeup(shared.wakeup_fd)));
-  for (auto& th : thds) {
-    th.Join();
-  }
-  fd.read_fd = 0;
-  grpc_wakeup_fd_destroy(&fd);
-  {
-    grpc_core::ExecCtx exec_ctx;
-    grpc_fd_shutdown(shared.wakeup_desc, GRPC_ERROR_CANCELLED);
-    grpc_fd_orphan(shared.wakeup_desc, nullptr, nullptr, "done");
-    grpc_pollset_shutdown(shared.pollset,
-                          GRPC_CLOSURE_CREATE(destroy_pollset, shared.pollset,
-                                              grpc_schedule_on_exec_ctx));
-  }
-  gpr_free(shared.pollset);
-}
-
-int main(int argc, char** argv) {
-  const char* poll_strategy = nullptr;
-  grpc_test_init(argc, argv);
-  grpc_init();
-  {
-    grpc_core::ExecCtx exec_ctx;
-
-    poll_strategy = grpc_get_poll_strategy_name();
-    if (poll_strategy != nullptr && strcmp(poll_strategy, "epollsig") == 0) {
-      test_add_fd_to_pollset();
-      test_threading();
-    } else {
-      gpr_log(GPR_INFO,
-              "Skipping the test. The test is only relevant for 'epollsig' "
-              "strategy. and the current strategy is: '%s'",
-              poll_strategy);
-    }
-  }
-
-  grpc_shutdown();
-  return 0;
-}
-#else  /* defined(GRPC_LINUX_EPOLL_CREATE1) */
-int main(int argc, char** argv) { return 0; }
-#endif /* !defined(GRPC_LINUX_EPOLL_CREATE1) */
diff --git a/test/core/iomgr/pollset_set_test.cc b/test/core/iomgr/pollset_set_test.cc
deleted file mode 100644
index 1aae1daa02..0000000000
--- a/test/core/iomgr/pollset_set_test.cc
+++ /dev/null
@@ -1,447 +0,0 @@
-/*
- *
- * Copyright 2016 gRPC authors.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- *
- */
-#include "src/core/lib/iomgr/port.h"
-
-/* This test only relevant on linux systems where epoll is available */
-#ifdef GRPC_LINUX_EPOLL_CREATE1
-
-#include <errno.h>
-#include <string.h>
-#include <unistd.h>
-
-#include <grpc/grpc.h>
-#include <grpc/support/alloc.h>
-#include <grpc/support/log.h>
-
-#include "src/core/lib/gpr/useful.h"
-#include "src/core/lib/iomgr/ev_posix.h"
-#include "src/core/lib/iomgr/iomgr.h"
-#include "test/core/util/test_config.h"
-
-/*******************************************************************************
- * test_pollset_set
- */
-
-typedef struct test_pollset_set {
-  grpc_pollset_set* pss;
-} test_pollset_set;
-
-void init_test_pollset_sets(test_pollset_set* pollset_sets, const int num_pss) {
-  for (int i = 0; i < num_pss; i++) {
-    pollset_sets[i].pss = grpc_pollset_set_create();
-  }
-}
-
-void cleanup_test_pollset_sets(test_pollset_set* pollset_sets,
-                               const int num_pss) {
-  for (int i = 0; i < num_pss; i++) {
-    grpc_pollset_set_destroy(pollset_sets[i].pss);
-    pollset_sets[i].pss = nullptr;
-  }
-}
-
-/*******************************************************************************
- * test_pollset
- */
-
-typedef struct test_pollset {
-  grpc_pollset* ps;
-  gpr_mu* mu;
-} test_pollset;
-
-static void init_test_pollsets(test_pollset* pollsets, const int num_pollsets) {
-  for (int i = 0; i < num_pollsets; i++) {
-    pollsets[i].ps =
-        static_cast<grpc_pollset*>(gpr_zalloc(grpc_pollset_size()));
-    grpc_pollset_init(pollsets[i].ps, &pollsets[i].mu);
-  }
-}
-
-static void destroy_pollset(void* p, grpc_error* error) {
-  grpc_pollset_destroy(static_cast<grpc_pollset*>(p));
-}
-
-static void cleanup_test_pollsets(test_pollset* pollsets,
-                                  const int num_pollsets) {
-  grpc_closure destroyed;
-  for (int i = 0; i < num_pollsets; i++) {
-    GRPC_CLOSURE_INIT(&destroyed, destroy_pollset, pollsets[i].ps,
-                      grpc_schedule_on_exec_ctx);
-    grpc_pollset_shutdown(pollsets[i].ps, &destroyed);
-
-    grpc_core::ExecCtx::Get()->Flush();
-    gpr_free(pollsets[i].ps);
-    pollsets[i].ps = nullptr;
-  }
-}
-
-/*******************************************************************************
- * test_fd
- */
-
-typedef struct test_fd {
-  grpc_fd* fd;
-  grpc_wakeup_fd wakeup_fd;
-
-  bool is_on_readable_called; /* Is on_readable closure is called ? */
-  grpc_closure on_readable;   /* Closure to call when this fd is readable */
-} test_fd;
-
-void on_readable(void* tfd, grpc_error* error) {
-  (static_cast<test_fd*>(tfd))->is_on_readable_called = true;
-}
-
-static void reset_test_fd(test_fd* tfd) {
-  tfd->is_on_readable_called = false;
-
-  GRPC_CLOSURE_INIT(&tfd->on_readable, on_readable, tfd,
-                    grpc_schedule_on_exec_ctx);
-  grpc_fd_notify_on_read(tfd->fd, &tfd->on_readable);
-}
-
-static void init_test_fds(test_fd* tfds, const int num_fds) {
-  for (int i = 0; i < num_fds; i++) {
-    GPR_ASSERT(GRPC_ERROR_NONE == grpc_wakeup_fd_init(&tfds[i].wakeup_fd));
-    tfds[i].fd = grpc_fd_create(GRPC_WAKEUP_FD_GET_READ_FD(&tfds[i].wakeup_fd),
-                                "test_fd", false);
-    reset_test_fd(&tfds[i]);
-  }
-}
-
-static void cleanup_test_fds(test_fd* tfds, const int num_fds) {
-  int release_fd;
-
-  for (int i = 0; i < num_fds; i++) {
-    grpc_fd_shutdown(tfds[i].fd,
-                     GRPC_ERROR_CREATE_FROM_STATIC_STRING("fd cleanup"));
-    grpc_core::ExecCtx::Get()->Flush();
-
-    /* grpc_fd_orphan frees the memory allocated for grpc_fd. Normally it also
-     * calls close() on the underlying fd. In our case, we are using
-     * grpc_wakeup_fd and we would like to destroy it ourselves (by calling
-     * grpc_wakeup_fd_destroy). To prevent grpc_fd from calling close() on the
-     * underlying fd, call it with a non-NULL 'release_fd' parameter */
-    grpc_fd_orphan(tfds[i].fd, nullptr, &release_fd, "test_fd_cleanup");
-    grpc_core::ExecCtx::Get()->Flush();
-
-    grpc_wakeup_fd_destroy(&tfds[i].wakeup_fd);
-  }
-}
-
-static void make_test_fds_readable(test_fd* tfds, const int num_fds) {
-  for (int i = 0; i < num_fds; i++) {
-    GPR_ASSERT(GRPC_ERROR_NONE == grpc_wakeup_fd_wakeup(&tfds[i].wakeup_fd));
-  }
-}
-
-static void verify_readable_and_reset(test_fd* tfds, const int num_fds) {
-  for (int i = 0; i < num_fds; i++) {
-    /* Verify that the on_readable callback was called */
-    GPR_ASSERT(tfds[i].is_on_readable_called);
-
-    /* Reset the tfd[i] structure */
-    GPR_ASSERT(GRPC_ERROR_NONE ==
-               grpc_wakeup_fd_consume_wakeup(&tfds[i].wakeup_fd));
-    reset_test_fd(&tfds[i]);
-  }
-}
-
-/*******************************************************************************
- * Main tests
- */
-
-/* Test some typical scenarios in pollset_set */
-static void pollset_set_test_basic() {
-  /* We construct the following structure for this test:
-   *
-   *        +---> FD0 (Added before PSS1, PS1 and PS2 are added to PSS0)
-   *        |
-   *        +---> FD5 (Added after PSS1, PS1 and PS2 are added to PSS0)
-   *        |
-   *        |
-   *        |           +---> FD1 (Added before PSS1 is added to PSS0)
-   *        |           |
-   *        |           +---> FD6 (Added after PSS1 is added to PSS0)
-   *        |           |
-   *        +---> PSS1--+           +--> FD2 (Added before PS0 is added to PSS1)
-   *        |           |           |
-   *        |           +---> PS0---+
-   *        |                       |
-   * PSS0---+                       +--> FD7 (Added after PS0 is added to PSS1)
-   *        |
-   *        |
-   *        |           +---> FD3 (Added before PS1 is added to PSS0)
-   *        |           |
-   *        +---> PS1---+
-   *        |           |
-   *        |           +---> FD8 (Added after PS1 added to PSS0)
-   *        |
-   *        |
-   *        |           +---> FD4 (Added before PS2 is added to PSS0)
-   *        |           |
-   *        +---> PS2---+
-   *                    |
-   *                    +---> FD9 (Added after PS2 is added to PSS0)
-   */
-  grpc_core::ExecCtx exec_ctx;
-  grpc_pollset_worker* worker;
-  grpc_millis deadline;
-
-  test_fd tfds[10];
-  test_pollset pollsets[3];
-  test_pollset_set pollset_sets[2];
-  const int num_fds = GPR_ARRAY_SIZE(tfds);
-  const int num_ps = GPR_ARRAY_SIZE(pollsets);
-  const int num_pss = GPR_ARRAY_SIZE(pollset_sets);
-
-  init_test_fds(tfds, num_fds);
-  init_test_pollsets(pollsets, num_ps);
-  init_test_pollset_sets(pollset_sets, num_pss);
-
-  /* Construct the pollset_set/pollset/fd tree (see diagram above) */
-
-  grpc_pollset_set_add_fd(pollset_sets[0].pss, tfds[0].fd);
-  grpc_pollset_set_add_fd(pollset_sets[1].pss, tfds[1].fd);
-
-  grpc_pollset_add_fd(pollsets[0].ps, tfds[2].fd);
-  grpc_pollset_add_fd(pollsets[1].ps, tfds[3].fd);
-  grpc_pollset_add_fd(pollsets[2].ps, tfds[4].fd);
-
-  grpc_pollset_set_add_pollset_set(pollset_sets[0].pss, pollset_sets[1].pss);
-
-  grpc_pollset_set_add_pollset(pollset_sets[1].pss, pollsets[0].ps);
-  grpc_pollset_set_add_pollset(pollset_sets[0].pss, pollsets[1].ps);
-  grpc_pollset_set_add_pollset(pollset_sets[0].pss, pollsets[2].ps);
-
-  grpc_pollset_set_add_fd(pollset_sets[0].pss, tfds[5].fd);
-  grpc_pollset_set_add_fd(pollset_sets[1].pss, tfds[6].fd);
-
-  grpc_pollset_add_fd(pollsets[0].ps, tfds[7].fd);
-  grpc_pollset_add_fd(pollsets[1].ps, tfds[8].fd);
-  grpc_pollset_add_fd(pollsets[2].ps, tfds[9].fd);
-
-  grpc_core::ExecCtx::Get()->Flush();
-
-  /* Test that if any FD in the above structure is readable, it is observable by
-   * doing grpc_pollset_work on any pollset
-   *
-   *   For every pollset, do the following:
-   *     - (Ensure that all FDs are in reset state)
-   *     - Make all FDs readable
-   *     - Call grpc_pollset_work() on the pollset
-   *     - Flush the exec_ctx
-   *     - Verify that on_readable call back was called for all FDs (and
-   *       reset the FDs)
-   * */
-  for (int i = 0; i < num_ps; i++) {
-    make_test_fds_readable(tfds, num_fds);
-
-    gpr_mu_lock(pollsets[i].mu);
-    deadline = grpc_timespec_to_millis_round_up(
-        grpc_timeout_milliseconds_to_deadline(2));
-    GPR_ASSERT(GRPC_ERROR_NONE ==
-               grpc_pollset_work(pollsets[i].ps, &worker, deadline));
-    gpr_mu_unlock(pollsets[i].mu);
-
-    grpc_core::ExecCtx::Get()->Flush();
-
-    verify_readable_and_reset(tfds, num_fds);
-    grpc_core::ExecCtx::Get()->Flush();
-  }
-
-  /* Test tear down */
-  grpc_pollset_set_del_fd(pollset_sets[0].pss, tfds[0].fd);
-  grpc_pollset_set_del_fd(pollset_sets[0].pss, tfds[5].fd);
-  grpc_pollset_set_del_fd(pollset_sets[1].pss, tfds[1].fd);
-  grpc_pollset_set_del_fd(pollset_sets[1].pss, tfds[6].fd);
-  grpc_core::ExecCtx::Get()->Flush();
-
-  grpc_pollset_set_del_pollset(pollset_sets[1].pss, pollsets[0].ps);
-  grpc_pollset_set_del_pollset(pollset_sets[0].pss, pollsets[1].ps);
-  grpc_pollset_set_del_pollset(pollset_sets[0].pss, pollsets[2].ps);
-
-  grpc_pollset_set_del_pollset_set(pollset_sets[0].pss, pollset_sets[1].pss);
-  grpc_core::ExecCtx::Get()->Flush();
-
-  cleanup_test_fds(tfds, num_fds);
-  cleanup_test_pollsets(pollsets, num_ps);
-  cleanup_test_pollset_sets(pollset_sets, num_pss);
-}
-
-/* Same FD added multiple times to the pollset_set tree */
-void pollset_set_test_dup_fds() {
-  /* We construct the following structure for this test:
-   *
-   *        +---> FD0
-   *        |
-   *        |
-   * PSS0---+
-   *        |           +---> FD0 (also under PSS0)
-   *        |           |
-   *        +---> PSS1--+           +--> FD1 (also under PSS1)
-   *                    |           |
-   *                    +---> PS ---+
-   *                    |           |
-   *                    |           +--> FD2
-   *                    +---> FD1
-   */
-  grpc_core::ExecCtx exec_ctx;
-  grpc_pollset_worker* worker;
-  grpc_millis deadline;
-
-  test_fd tfds[3];
-  test_pollset pollset;
-  test_pollset_set pollset_sets[2];
-  const int num_fds = GPR_ARRAY_SIZE(tfds);
-  const int num_ps = 1;
-  const int num_pss = GPR_ARRAY_SIZE(pollset_sets);
-
-  init_test_fds(tfds, num_fds);
-  init_test_pollsets(&pollset, num_ps);
-  init_test_pollset_sets(pollset_sets, num_pss);
-
-  /* Construct the structure */
-  grpc_pollset_set_add_fd(pollset_sets[0].pss, tfds[0].fd);
-  grpc_pollset_set_add_fd(pollset_sets[1].pss, tfds[0].fd);
-  grpc_pollset_set_add_fd(pollset_sets[1].pss, tfds[1].fd);
-
-  grpc_pollset_add_fd(pollset.ps, tfds[1].fd);
-  grpc_pollset_add_fd(pollset.ps, tfds[2].fd);
-
-  grpc_pollset_set_add_pollset(pollset_sets[1].pss, pollset.ps);
-  grpc_pollset_set_add_pollset_set(pollset_sets[0].pss, pollset_sets[1].pss);
-
-  /* Test. Make all FDs readable and make sure that can be observed by doing a
-   * grpc_pollset_work on the pollset 'PS' */
-  make_test_fds_readable(tfds, num_fds);
-
-  gpr_mu_lock(pollset.mu);
-  deadline = grpc_timespec_to_millis_round_up(
-      grpc_timeout_milliseconds_to_deadline(2));
-  GPR_ASSERT(GRPC_ERROR_NONE ==
-             grpc_pollset_work(pollset.ps, &worker, deadline));
-  gpr_mu_unlock(pollset.mu);
-  grpc_core::ExecCtx::Get()->Flush();
-
-  verify_readable_and_reset(tfds, num_fds);
-  grpc_core::ExecCtx::Get()->Flush();
-
-  /* Tear down */
-  grpc_pollset_set_del_fd(pollset_sets[0].pss, tfds[0].fd);
-  grpc_pollset_set_del_fd(pollset_sets[1].pss, tfds[0].fd);
-  grpc_pollset_set_del_fd(pollset_sets[1].pss, tfds[1].fd);
-
-  grpc_pollset_set_del_pollset(pollset_sets[1].pss, pollset.ps);
-  grpc_pollset_set_del_pollset_set(pollset_sets[0].pss, pollset_sets[1].pss);
-  grpc_core::ExecCtx::Get()->Flush();
-
-  cleanup_test_fds(tfds, num_fds);
-  cleanup_test_pollsets(&pollset, num_ps);
-  cleanup_test_pollset_sets(pollset_sets, num_pss);
-}
-
-/* Pollset_set with an empty pollset */
-void pollset_set_test_empty_pollset() {
-  /* We construct the following structure for this test:
-   *
-   *        +---> PS0 (EMPTY)
-   *        |
-   *        +---> FD0
-   *        |
-   * PSS0---+
-   *        |          +---> FD1
-   *        |          |
-   *        +---> PS1--+
-   *                   |
-   *                   +---> FD2
-   */
-  grpc_core::ExecCtx exec_ctx;
-  grpc_pollset_worker* worker;
-  grpc_millis deadline;
-
-  test_fd tfds[3];
-  test_pollset pollsets[2];
-  test_pollset_set pollset_set;
-  const int num_fds = GPR_ARRAY_SIZE(tfds);
-  const int num_ps = GPR_ARRAY_SIZE(pollsets);
-  const int num_pss = 1;
-
-  init_test_fds(tfds, num_fds);
-  init_test_pollsets(pollsets, num_ps);
-  init_test_pollset_sets(&pollset_set, num_pss);
-
-  /* Construct the structure */
-  grpc_pollset_set_add_fd(pollset_set.pss, tfds[0].fd);
-  grpc_pollset_add_fd(pollsets[1].ps, tfds[1].fd);
-  grpc_pollset_add_fd(pollsets[1].ps, tfds[2].fd);
-
-  grpc_pollset_set_add_pollset(pollset_set.pss, pollsets[0].ps);
-  grpc_pollset_set_add_pollset(pollset_set.pss, pollsets[1].ps);
-
-  /* Test. Make all FDs readable and make sure that can be observed by doing
-   * grpc_pollset_work on the empty pollset 'PS0' */
-  make_test_fds_readable(tfds, num_fds);
-
-  gpr_mu_lock(pollsets[0].mu);
-  deadline = grpc_timespec_to_millis_round_up(
-      grpc_timeout_milliseconds_to_deadline(2));
-  GPR_ASSERT(GRPC_ERROR_NONE ==
-             grpc_pollset_work(pollsets[0].ps, &worker, deadline));
-  gpr_mu_unlock(pollsets[0].mu);
-  grpc_core::ExecCtx::Get()->Flush();
-
-  verify_readable_and_reset(tfds, num_fds);
-  grpc_core::ExecCtx::Get()->Flush();
-
-  /* Tear down */
-  grpc_pollset_set_del_fd(pollset_set.pss, tfds[0].fd);
-  grpc_pollset_set_del_pollset(pollset_set.pss, pollsets[0].ps);
-  grpc_pollset_set_del_pollset(pollset_set.pss, pollsets[1].ps);
-  grpc_core::ExecCtx::Get()->Flush();
-
-  cleanup_test_fds(tfds, num_fds);
-  cleanup_test_pollsets(pollsets, num_ps);
-  cleanup_test_pollset_sets(&pollset_set, num_pss);
-}
-
-int main(int argc, char** argv) {
-  grpc_test_init(argc, argv);
-  grpc_init();
-  {
-    grpc_core::ExecCtx exec_ctx;
-    const char* poll_strategy = grpc_get_poll_strategy_name();
-
-    if (poll_strategy != nullptr &&
-        (strcmp(poll_strategy, "epollsig") == 0 ||
-         strcmp(poll_strategy, "epoll-threadpool") == 0)) {
-      pollset_set_test_basic();
-      pollset_set_test_dup_fds();
-      pollset_set_test_empty_pollset();
-    } else {
-      gpr_log(GPR_INFO,
-              "Skipping the test. The test is only relevant for 'epoll' "
-              "strategy. and the current strategy is: '%s'",
-              poll_strategy);
-    }
-  }
-  grpc_shutdown();
-  return 0;
-}
-#else  /* defined(GRPC_LINUX_EPOLL_CREATE1) */
-int main(int argc, char** argv) { return 0; }
-#endif /* !defined(GRPC_LINUX_EPOLL_CREATE1) */
diff --git a/test/core/iomgr/resolve_address_test.cc b/test/core/iomgr/resolve_address_test.cc
index 2fb831a6a4..8d69bab5b1 100644
--- a/test/core/iomgr/resolve_address_test.cc
+++ b/test/core/iomgr/resolve_address_test.cc
@@ -22,8 +22,14 @@
 #include <grpc/support/log.h>
 #include <grpc/support/sync.h>
 #include <grpc/support/time.h>
+
+#include <string.h>
+
+#include "src/core/lib/gpr/env.h"
+#include "src/core/lib/gpr/string.h"
 #include "src/core/lib/iomgr/executor.h"
 #include "src/core/lib/iomgr/iomgr.h"
+#include "test/core/util/cmdline.h"
 #include "test/core/util/test_config.h"
 
 static gpr_timespec test_deadline(void) {
@@ -240,6 +246,31 @@ static void test_unparseable_hostports(void) {
 }
 
 int main(int argc, char** argv) {
+  // First set the resolver type based off of --resolver
+  const char* resolver_type = nullptr;
+  gpr_cmdline* cl = gpr_cmdline_create("resolve address test");
+  gpr_cmdline_add_string(cl, "resolver", "Resolver type (ares or native)",
+                         &resolver_type);
+  // In case that there are more than one argument on the command line,
+  // --resolver will always be the first one, so only parse the first argument
+  // (other arguments may be unknown to cl)
+  gpr_cmdline_parse(cl, argc > 2 ? 2 : argc, argv);
+  const char* cur_resolver = gpr_getenv("GRPC_DNS_RESOLVER");
+  if (cur_resolver != nullptr && strlen(cur_resolver) != 0) {
+    gpr_log(GPR_INFO, "Warning: overriding resolver setting of %s",
+            cur_resolver);
+  }
+  if (gpr_stricmp(resolver_type, "native") == 0) {
+    gpr_setenv("GRPC_DNS_RESOLVER", "native");
+  } else if (gpr_stricmp(resolver_type, "ares") == 0) {
+#ifndef GRPC_UV
+    gpr_setenv("GRPC_DNS_RESOLVER", "ares");
+#endif
+  } else {
+    gpr_log(GPR_ERROR, "--resolver_type was not set to ares or native");
+    abort();
+  }
+  // Run the test.
   grpc_test_init(argc, argv);
   grpc_init();
   {
@@ -250,10 +281,18 @@ int main(int argc, char** argv) {
     test_missing_default_port();
     test_ipv6_with_port();
     test_ipv6_without_port();
-    test_invalid_ip_addresses();
-    test_unparseable_hostports();
+    if (gpr_stricmp(resolver_type, "ares") != 0) {
+      // These tests can trigger DNS queries to the nearby nameserver
+      // that need to come back in order for the test to succeed.
+      // c-ares is prone to not using the local system caches that the
+      // native getaddrinfo implementations take advantage of, so running
+      // these unit tests under c-ares risks flakiness.
+      test_invalid_ip_addresses();
+      test_unparseable_hostports();
+    }
     grpc_executor_shutdown();
   }
+  gpr_cmdline_destroy(cl);
 
   grpc_shutdown();
   return 0;
diff --git a/test/core/iomgr/tcp_client_posix_test.cc b/test/core/iomgr/tcp_client_posix_test.cc
index a4c38af86f..90fc5aecfc 100644
--- a/test/core/iomgr/tcp_client_posix_test.cc
+++ b/test/core/iomgr/tcp_client_posix_test.cc
@@ -170,7 +170,7 @@ void test_fails(void) {
         break;
       case GRPC_TIMERS_NOT_CHECKED:
         polling_deadline = 0;
-      /* fall through */
+      // fallthrough
       case GRPC_TIMERS_CHECKED_AND_EMPTY:
         GPR_ASSERT(GRPC_LOG_IF_ERROR(
             "pollset_work",
diff --git a/test/core/iomgr/tcp_client_uv_test.cc b/test/core/iomgr/tcp_client_uv_test.cc
index 0c6250ed7f..27f894e3f3 100644
--- a/test/core/iomgr/tcp_client_uv_test.cc
+++ b/test/core/iomgr/tcp_client_uv_test.cc
@@ -129,6 +129,7 @@ void test_succeeds(void) {
   uv_close((uv_handle_t*)svr_handle, close_cb);
 
   gpr_mu_unlock(g_mu);
+  grpc_core::ExecCtx::Get()->Flush();
 }
 
 void test_fails(void) {
@@ -165,7 +166,7 @@ void test_fails(void) {
         break;
       case GRPC_TIMERS_NOT_CHECKED:
         polling_deadline = grpc_timespec_to_millis_round_up(now);
-      /* fall through */
+      // fallthrough
       case GRPC_TIMERS_CHECKED_AND_EMPTY:
         GPR_ASSERT(GRPC_LOG_IF_ERROR(
             "pollset_work",
@@ -178,6 +179,7 @@ void test_fails(void) {
   }
 
   gpr_mu_unlock(g_mu);
+  grpc_core::ExecCtx::Get()->Flush();
 }
 
 static void destroy_pollset(void* p, grpc_error* error) {
@@ -186,21 +188,22 @@ static void destroy_pollset(void* p, grpc_error* error) {
 
 int main(int argc, char** argv) {
   grpc_closure destroyed;
-  grpc_core::ExecCtx exec_ctx;
   grpc_test_init(argc, argv);
   grpc_init();
-  g_pollset = static_cast<grpc_pollset*>(gpr_malloc(grpc_pollset_size()));
-  grpc_pollset_init(g_pollset, &g_mu);
-
-  test_succeeds();
-  gpr_log(GPR_ERROR, "End of first test");
-  test_fails();
-  GRPC_CLOSURE_INIT(&destroyed, destroy_pollset, g_pollset,
-                    grpc_schedule_on_exec_ctx);
-  grpc_pollset_shutdown(g_pollset, &destroyed);
-
+  {
+    grpc_core::ExecCtx exec_ctx;
+    g_pollset = static_cast<grpc_pollset*>(gpr_malloc(grpc_pollset_size()));
+    grpc_pollset_init(g_pollset, &g_mu);
+
+    test_succeeds();
+    gpr_log(GPR_ERROR, "End of first test");
+    test_fails();
+    GRPC_CLOSURE_INIT(&destroyed, destroy_pollset, g_pollset,
+                      grpc_schedule_on_exec_ctx);
+    grpc_pollset_shutdown(g_pollset, &destroyed);
+    gpr_free(g_pollset);
+  }
   grpc_shutdown();
-  gpr_free(g_pollset);
   return 0;
 }
 
diff --git a/test/core/iomgr/tcp_server_uv_test.cc b/test/core/iomgr/tcp_server_uv_test.cc
index 35d62b51b7..e99fa79bfd 100644
--- a/test/core/iomgr/tcp_server_uv_test.cc
+++ b/test/core/iomgr/tcp_server_uv_test.cc
@@ -119,6 +119,7 @@ static void test_no_op(void) {
   grpc_tcp_server* s;
   GPR_ASSERT(GRPC_ERROR_NONE == grpc_tcp_server_create(NULL, NULL, &s));
   grpc_tcp_server_unref(s);
+  grpc_core::ExecCtx::Get()->Flush();
 }
 
 static void test_no_op_with_start(void) {
@@ -128,6 +129,7 @@ static void test_no_op_with_start(void) {
   LOG_TEST("test_no_op_with_start");
   grpc_tcp_server_start(s, NULL, 0, on_connect, NULL);
   grpc_tcp_server_unref(s);
+  grpc_core::ExecCtx::Get()->Flush();
 }
 
 static void test_no_op_with_port(void) {
@@ -147,6 +149,7 @@ static void test_no_op_with_port(void) {
              port > 0);
 
   grpc_tcp_server_unref(s);
+  grpc_core::ExecCtx::Get()->Flush();
 }
 
 static void test_no_op_with_port_and_start(void) {
@@ -168,6 +171,7 @@ static void test_no_op_with_port_and_start(void) {
   grpc_tcp_server_start(s, NULL, 0, on_connect, NULL);
 
   grpc_tcp_server_unref(s);
+  grpc_core::ExecCtx::Get()->Flush();
 }
 
 static void connect_cb(uv_connect_t* req, int status) {
@@ -273,7 +277,7 @@ static void test_connect(unsigned n) {
   GPR_ASSERT(weak_ref.server != NULL);
 
   grpc_tcp_server_unref(s);
-
+  grpc_core::ExecCtx::Get()->Flush();
   /* Weak ref lost. */
   GPR_ASSERT(weak_ref.server == NULL);
 }
@@ -284,25 +288,27 @@ static void destroy_pollset(void* p, grpc_error* error) {
 
 int main(int argc, char** argv) {
   grpc_closure destroyed;
-  grpc_core::ExecCtx exec_ctx;
   grpc_test_init(argc, argv);
   grpc_init();
-  g_pollset = static_cast<grpc_pollset*>(gpr_malloc(grpc_pollset_size()));
-  grpc_pollset_init(g_pollset, &g_mu);
-
-  test_no_op();
-  test_no_op_with_start();
-  test_no_op_with_port();
-  test_no_op_with_port_and_start();
-  test_connect(1);
-  test_connect(10);
-
-  GRPC_CLOSURE_INIT(&destroyed, destroy_pollset, g_pollset,
-                    grpc_schedule_on_exec_ctx);
-  grpc_pollset_shutdown(g_pollset, &destroyed);
-
+  {
+    grpc_core::ExecCtx exec_ctx;
+    g_pollset = static_cast<grpc_pollset*>(gpr_malloc(grpc_pollset_size()));
+    grpc_pollset_init(g_pollset, &g_mu);
+
+    test_no_op();
+    test_no_op_with_start();
+    test_no_op_with_port();
+    test_no_op_with_port_and_start();
+    test_connect(1);
+    test_connect(10);
+
+    GRPC_CLOSURE_INIT(&destroyed, destroy_pollset, g_pollset,
+                      grpc_schedule_on_exec_ctx);
+    grpc_pollset_shutdown(g_pollset, &destroyed);
+
+    gpr_free(g_pollset);
+  }
   grpc_shutdown();
-  gpr_free(g_pollset);
   return 0;
 }
 
diff --git a/test/core/iomgr/timer_list_test.cc b/test/core/iomgr/timer_list_test.cc
index feedf3f149..fd65d1abf1 100644
--- a/test/core/iomgr/timer_list_test.cc
+++ b/test/core/iomgr/timer_list_test.cc
@@ -248,11 +248,7 @@ int main(int argc, char** argv) {
     grpc_determine_iomgr_platform();
     grpc_iomgr_platform_init();
     gpr_set_log_verbosity(GPR_LOG_SEVERITY_DEBUG);
-#ifndef GPR_WINDOWS
-    /* Skip this test on Windows until we figure out why it fails */
-    /* https://github.com/grpc/grpc/issues/16417 */
     long_running_service_cleanup_test();
-#endif  // GPR_WINDOWS
     add_test();
     destruction_test();
     grpc_iomgr_platform_shutdown();