diff --git a/src/core/ext/filters/client_channel/resolver/dns/c_ares/dns_resolver_ares.cc b/src/core/ext/filters/client_channel/resolver/dns/c_ares/dns_resolver_ares.cc
index bf8b0ea5f62..fe245bfef09 100644
--- a/src/core/ext/filters/client_channel/resolver/dns/c_ares/dns_resolver_ares.cc
+++ b/src/core/ext/filters/client_channel/resolver/dns/c_ares/dns_resolver_ares.cc
@@ -478,8 +478,7 @@ static grpc_address_resolver_vtable ares_resolver = {
     grpc_resolve_address_ares, blocking_resolve_address_ares};
 
 static bool should_use_ares(const char* resolver_env) {
-  return resolver_env == nullptr || strlen(resolver_env) == 0 ||
-         gpr_stricmp(resolver_env, "ares") == 0;
+  return resolver_env != nullptr && gpr_stricmp(resolver_env, "ares") == 0;
 }
 
 void grpc_resolver_dns_ares_init() {
diff --git a/templates/test/cpp/naming/resolver_component_tests_defs.include b/templates/test/cpp/naming/resolver_component_tests_defs.include
index d38316cbe68..b34845e01a3 100644
--- a/templates/test/cpp/naming/resolver_component_tests_defs.include
+++ b/templates/test/cpp/naming/resolver_component_tests_defs.include
@@ -55,6 +55,7 @@ if cur_resolver and cur_resolver != 'ares':
       'needs to use GRPC_DNS_RESOLVER=ares.'))
   test_runner_log('Exit 1 without running tests.')
   sys.exit(1)
+os.environ.update({'GRPC_DNS_RESOLVER': 'ares'})
 os.environ.update({'GRPC_TRACE': 'cares_resolver'})
 
 def wait_until_dns_server_is_up(args,
diff --git a/test/core/client_channel/resolvers/dns_resolver_test.cc b/test/core/client_channel/resolvers/dns_resolver_test.cc
index 6f153cc9bf6..f426eab9592 100644
--- a/test/core/client_channel/resolvers/dns_resolver_test.cc
+++ b/test/core/client_channel/resolvers/dns_resolver_test.cc
@@ -75,7 +75,7 @@ int main(int argc, char** argv) {
   test_succeeds(dns, "dns:www.google.com");
   test_succeeds(dns, "dns:///www.google.com");
   char* resolver_env = gpr_getenv("GRPC_DNS_RESOLVER");
-  if (resolver_env != nullptr && gpr_stricmp(resolver_env, "native") == 0) {
+  if (resolver_env == nullptr || gpr_stricmp(resolver_env, "native") == 0) {
     test_fails(dns, "dns://8.8.8.8/8.8.8.8:8888");
   } else {
     test_succeeds(dns, "dns://8.8.8.8/8.8.8.8:8888");
diff --git a/test/cpp/naming/resolver_component_tests_runner.py b/test/cpp/naming/resolver_component_tests_runner.py
index a4438cb100e..8a5b1f53dcf 100755
--- a/test/cpp/naming/resolver_component_tests_runner.py
+++ b/test/cpp/naming/resolver_component_tests_runner.py
@@ -55,6 +55,7 @@ if cur_resolver and cur_resolver != 'ares':
       'needs to use GRPC_DNS_RESOLVER=ares.'))
   test_runner_log('Exit 1 without running tests.')
   sys.exit(1)
+os.environ.update({'GRPC_DNS_RESOLVER': 'ares'})
 os.environ.update({'GRPC_TRACE': 'cares_resolver'})
 
 def wait_until_dns_server_is_up(args,