diff --git a/test/ares-test-mock.cc b/test/ares-test-mock.cc
index 81bcf281..36fcdadf 100644
--- a/test/ares-test-mock.cc
+++ b/test/ares-test-mock.cc
@@ -11,7 +11,7 @@ using testing::InvokeWithoutArgs;
 namespace ares {
 namespace test {
 
-TEST_F(MockChannelTest, Basic) {
+TEST_P(MockChannelTest, Basic) {
   std::vector<byte> reply = {
     0x00, 0x00,  // qid
     0x84, // response + query + AA + not-TC + not-RD
@@ -51,7 +51,7 @@ TEST_F(MockChannelTest, Basic) {
   EXPECT_EQ("{'www.google.com' aliases=[] addrs=[1.2.3.4]}", ss.str());
 }
 
-TEST_F(MockChannelTest, SearchDomains) {
+TEST_P(MockChannelTest, SearchDomains) {
   DNSPacket nofirst;
   nofirst.set_response().set_aa().set_rcode(ns_r_nxdomain)
     .add_question(new DNSQuestion("www.first.com", ns_t_a));
@@ -78,7 +78,7 @@ TEST_F(MockChannelTest, SearchDomains) {
   EXPECT_EQ("{'www.third.gov' aliases=[] addrs=[2.3.4.5]}", ss.str());
 }
 
-TEST_F(MockChannelTest, SearchDomainsBare) {
+TEST_P(MockChannelTest, SearchDomainsBare) {
   DNSPacket nofirst;
   nofirst.set_response().set_aa().set_rcode(ns_r_nxdomain)
     .add_question(new DNSQuestion("www.first.com", ns_t_a));
@@ -110,7 +110,7 @@ TEST_F(MockChannelTest, SearchDomainsBare) {
   EXPECT_EQ("{'www' aliases=[] addrs=[2.3.4.5]}", ss.str());
 }
 
-TEST_F(MockChannelTest, SearchNoDataThenSuccess) {
+TEST_P(MockChannelTest, SearchNoDataThenSuccess) {
   // First two search domains recognize the name but have no A records.
   DNSPacket nofirst;
   nofirst.set_response().set_aa()
@@ -138,7 +138,7 @@ TEST_F(MockChannelTest, SearchNoDataThenSuccess) {
   EXPECT_EQ("{'www.third.gov' aliases=[] addrs=[2.3.4.5]}", ss.str());
 }
 
-TEST_F(MockChannelTest, SearchNoDataThenFail) {
+TEST_P(MockChannelTest, SearchNoDataThenFail) {
   // First two search domains recognize the name but have no A records.
   DNSPacket nofirst;
   nofirst.set_response().set_aa()
@@ -168,7 +168,7 @@ TEST_F(MockChannelTest, SearchNoDataThenFail) {
   EXPECT_EQ(ARES_ENODATA, result.status_);
 }
 
-TEST_F(MockChannelTest, SearchAllocFailure) {
+TEST_P(MockChannelTest, SearchAllocFailure) {
   SearchResult result;
   SetAllocFail(1);
   ares_search(channel_, "fully.qualified.", ns_c_in, ns_t_a, SearchCallback, &result);
@@ -177,7 +177,7 @@ TEST_F(MockChannelTest, SearchAllocFailure) {
   EXPECT_EQ(ARES_ENOMEM, result.status_);
 }
 
-TEST_F(MockChannelTest, SearchHighNdots) {
+TEST_P(MockChannelTest, SearchHighNdots) {
   DNSPacket nobare;
   nobare.set_response().set_aa().set_rcode(ns_r_nxdomain)
     .add_question(new DNSQuestion("a.b.c.w.w.w", ns_t_a));
@@ -202,7 +202,7 @@ TEST_F(MockChannelTest, SearchHighNdots) {
             ss.str());
 }
 
-TEST_F(MockChannelTest, UnspecifiedFamilyV6) {
+TEST_P(MockChannelTest, UnspecifiedFamilyV6) {
   DNSPacket rsp6;
   rsp6.set_response().set_aa()
     .add_question(new DNSQuestion("example.com", ns_t_aaaa))
@@ -222,7 +222,7 @@ TEST_F(MockChannelTest, UnspecifiedFamilyV6) {
   EXPECT_EQ("{'example.com' aliases=[] addrs=[2121:0000:0000:0000:0000:0000:0000:0303]}", ss.str());
 }
 
-TEST_F(MockChannelTest, UnspecifiedFamilyV4) {
+TEST_P(MockChannelTest, UnspecifiedFamilyV4) {
   DNSPacket rsp4;
   rsp4.set_response().set_aa()
     .add_question(new DNSQuestion("example.com", ns_t_a))
@@ -244,7 +244,7 @@ TEST_F(MockChannelTest, UnspecifiedFamilyV4) {
   EXPECT_EQ("{'example.com' aliases=[] addrs=[2.3.4.5]}", ss.str());
 }
 
-TEST_F(MockChannelTest, UnspecifiedFamilyNoData) {
+TEST_P(MockChannelTest, UnspecifiedFamilyNoData) {
   DNSPacket rsp4;
   rsp4.set_response().set_aa()
     .add_question(new DNSQuestion("example.com", ns_t_a));
@@ -266,7 +266,7 @@ TEST_F(MockChannelTest, UnspecifiedFamilyNoData) {
   EXPECT_EQ("{'' aliases=[] addrs=[]}", ss.str());
 }
 
-TEST_F(MockChannelTest, ExplicitIP) {
+TEST_P(MockChannelTest, ExplicitIP) {
   HostResult result;
   ares_gethostbyname(channel_, "1.2.3.4", AF_INET, HostCallback, &result);
   EXPECT_TRUE(result.done_);  // Immediate return
@@ -276,7 +276,7 @@ TEST_F(MockChannelTest, ExplicitIP) {
   EXPECT_EQ("{'1.2.3.4' aliases=[] addrs=[1.2.3.4]}", ss.str());
 }
 
-TEST_F(MockChannelTest, ExplicitIPAllocFail) {
+TEST_P(MockChannelTest, ExplicitIPAllocFail) {
   HostResult result;
   SetAllocSizeFail(strlen("1.2.3.4") + 1);
   ares_gethostbyname(channel_, "1.2.3.4", AF_INET, HostCallback, &result);
@@ -284,7 +284,7 @@ TEST_F(MockChannelTest, ExplicitIPAllocFail) {
   EXPECT_EQ(ARES_ENOMEM, result.status_);
 }
 
-TEST_F(MockChannelTest, SortListV4) {
+TEST_P(MockChannelTest, SortListV4) {
   DNSPacket rsp;
   rsp.set_response().set_aa()
     .add_question(new DNSQuestion("example.com", ns_t_a))
@@ -322,7 +322,7 @@ TEST_F(MockChannelTest, SortListV4) {
   ares_destroy_options(&options);
 }
 
-TEST_F(MockChannelTest, SortListV6) {
+TEST_P(MockChannelTest, SortListV6) {
   DNSPacket rsp;
   rsp.set_response().set_aa()
     .add_question(new DNSQuestion("example.com", ns_t_aaaa))
@@ -359,7 +359,7 @@ TEST_F(MockChannelTest, SortListV6) {
   }
 }
 
-TEST_F(MockChannelTest, SearchDomainsAllocFail) {
+TEST_P(MockChannelTest, SearchDomainsAllocFail) {
   DNSPacket nofirst;
   nofirst.set_response().set_aa().set_rcode(ns_r_nxdomain)
     .add_question(new DNSQuestion("www.first.com", ns_t_a));
@@ -403,7 +403,7 @@ TEST_F(MockChannelTest, SearchDomainsAllocFail) {
   channel_ = nullptr;
 }
 
-TEST_F(MockChannelTest, Resend) {
+TEST_P(MockChannelTest, Resend) {
   std::vector<byte> nothing;
   DNSPacket reply;
   reply.set_response().set_aa()
@@ -425,7 +425,7 @@ TEST_F(MockChannelTest, Resend) {
   EXPECT_EQ("{'www.google.com' aliases=[] addrs=[1.2.3.4]}", ss.str());
 }
 
-TEST_F(MockChannelTest, CancelImmediate) {
+TEST_P(MockChannelTest, CancelImmediate) {
   HostResult result;
   ares_gethostbyname(channel_, "www.google.com.", AF_INET, HostCallback, &result);
   ares_cancel(channel_);
@@ -434,7 +434,7 @@ TEST_F(MockChannelTest, CancelImmediate) {
   EXPECT_EQ(0, result.timeouts_);
 }
 
-TEST_F(MockChannelTest, CancelLater) {
+TEST_P(MockChannelTest, CancelLater) {
   std::vector<byte> nothing;
 
   // On second request, cancel the channel.
@@ -450,7 +450,7 @@ TEST_F(MockChannelTest, CancelLater) {
   EXPECT_EQ(0, result.timeouts_);
 }
 
-TEST_F(MockChannelTest, GetHostByNameDestroyAbsolute) {
+TEST_P(MockChannelTest, GetHostByNameDestroyAbsolute) {
   HostResult result;
   ares_gethostbyname(channel_, "www.google.com.", AF_INET, HostCallback, &result);
 
@@ -462,7 +462,7 @@ TEST_F(MockChannelTest, GetHostByNameDestroyAbsolute) {
   EXPECT_EQ(0, result.timeouts_);
 }
 
-TEST_F(MockChannelTest, GetHostByNameDestroyRelative) {
+TEST_P(MockChannelTest, GetHostByNameDestroyRelative) {
   HostResult result;
   ares_gethostbyname(channel_, "www", AF_INET, HostCallback, &result);
 
@@ -474,7 +474,7 @@ TEST_F(MockChannelTest, GetHostByNameDestroyRelative) {
   EXPECT_EQ(0, result.timeouts_);
 }
 
-TEST_F(MockChannelTest, GetHostByAddrDestroy) {
+TEST_P(MockChannelTest, GetHostByAddrDestroy) {
   unsigned char gdns_addr4[4] = {0x08, 0x08, 0x08, 0x08};
   HostResult result;
   ares_gethostbyaddr(channel_, gdns_addr4, sizeof(gdns_addr4), AF_INET, HostCallback, &result);
@@ -487,7 +487,7 @@ TEST_F(MockChannelTest, GetHostByAddrDestroy) {
   EXPECT_EQ(0, result.timeouts_);
 }
 
-TEST_F(MockChannelTest, HostAlias) {
+TEST_P(MockChannelTest, HostAlias) {
   DNSPacket reply;
   reply.set_response().set_aa()
     .add_question(new DNSQuestion("www.google.com", ns_t_a))
@@ -507,7 +507,7 @@ TEST_F(MockChannelTest, HostAlias) {
   EXPECT_EQ("{'www.google.com' aliases=[] addrs=[1.2.3.4]}", ss.str());
 }
 
-TEST_F(MockChannelTest, HostAliasMissing) {
+TEST_P(MockChannelTest, HostAliasMissing) {
   DNSPacket yesfirst;
   yesfirst.set_response().set_aa()
     .add_question(new DNSQuestion("www.first.com", ns_t_a))
@@ -526,7 +526,7 @@ TEST_F(MockChannelTest, HostAliasMissing) {
   EXPECT_EQ("{'www.first.com' aliases=[] addrs=[2.3.4.5]}", ss.str());
 }
 
-TEST_F(MockChannelTest, HostAliasMissingFile) {
+TEST_P(MockChannelTest, HostAliasMissingFile) {
   DNSPacket yesfirst;
   yesfirst.set_response().set_aa()
     .add_question(new DNSQuestion("www.first.com", ns_t_a))
@@ -544,7 +544,7 @@ TEST_F(MockChannelTest, HostAliasMissingFile) {
   EXPECT_EQ("{'www.first.com' aliases=[] addrs=[2.3.4.5]}", ss.str());
 }
 
-TEST_F(MockChannelTest, HostAliasUnreadable) {
+TEST_P(MockChannelTest, HostAliasUnreadable) {
   TempFile aliases("www www.google.com\n");
   chmod(aliases.filename(), 0);
   EnvValue with_env("HOSTALIASES", aliases.filename());
@@ -556,5 +556,8 @@ TEST_F(MockChannelTest, HostAliasUnreadable) {
   chmod(aliases.filename(), 0777);
 }
 
+INSTANTIATE_TEST_CASE_P(AddressFamilies, MockChannelTest,
+                        ::testing::Values(AF_INET, AF_INET6));
+
 }  // namespace test
 }  // namespace ares
diff --git a/test/ares-test.cc b/test/ares-test.cc
index 92cdb093..a2007ede 100644
--- a/test/ares-test.cc
+++ b/test/ares-test.cc
@@ -121,19 +121,30 @@ void DefaultChannelModeTest::Process() {
   ProcessWork(channel_, -1, nullptr);
 }
 
-MockServer::MockServer(int port) : port_(port) {
+MockServer::MockServer(int family, int port) : port_(port) {
   // Create a UDP socket to receive data on.
-  sockfd_ = socket(AF_INET, SOCK_DGRAM, 0);
+  sockfd_ = socket(family, SOCK_DGRAM, 0);
   EXPECT_NE(-1, sockfd_);
 
   // Bind it to the given port.
-  struct sockaddr_in addr;
-  memset(&addr, 0, sizeof(addr));
-  addr.sin_family = AF_INET;
-  addr.sin_addr.s_addr = htonl(INADDR_ANY);
-  addr.sin_port = htons(port_);
-  int rc = bind(sockfd_, (struct sockaddr*)&addr, sizeof(addr));
-  EXPECT_EQ(0, rc) << "Failed to bind to port " << port_;
+  if (family == AF_INET) {
+    struct sockaddr_in addr;
+    memset(&addr, 0, sizeof(addr));
+    addr.sin_family = AF_INET;
+    addr.sin_addr.s_addr = htonl(INADDR_ANY);
+    addr.sin_port = htons(port_);
+    int rc = bind(sockfd_, (struct sockaddr*)&addr, sizeof(addr));
+    EXPECT_EQ(0, rc) << "Failed to bind AF_INET to port " << port_;
+  } else {
+    EXPECT_EQ(AF_INET6, family);
+    struct sockaddr_in6 addr;
+    memset(&addr, 0, sizeof(addr));
+    addr.sin6_family = AF_INET6;
+    addr.sin6_addr = in6addr_any;
+    addr.sin6_port = htons(port_);
+    int rc = bind(sockfd_, (struct sockaddr*)&addr, sizeof(addr));
+    EXPECT_EQ(0, rc) << "Failed to bind AF_INET6 to port " << port_;
+  }
 }
 
 MockServer::~MockServer() {
@@ -223,9 +234,10 @@ void MockServer::ProcessRequest(struct sockaddr_storage* addr, int addrlen,
   }
 }
 
-MockChannelOptsTest::MockChannelOptsTest(struct ares_options* givenopts,
+MockChannelOptsTest::MockChannelOptsTest(int family,
+                                         struct ares_options* givenopts,
                                          int optmask)
-  : server_(mock_port), channel_(nullptr) {
+  : server_(family, mock_port), channel_(nullptr) {
   // Set up channel options.
   struct ares_options opts;
   if (givenopts) {
@@ -242,10 +254,12 @@ MockChannelOptsTest::MockChannelOptsTest(struct ares_options* givenopts,
   optmask |= ARES_OPT_TCP_PORT;
   opts.nservers = 1;
   struct in_addr server_addr;
-  memset(&server_addr, 0, sizeof(server_addr));
-  server_addr.s_addr = htonl(0x7F000001);
-  opts.servers = &server_addr;
-  optmask |= ARES_OPT_SERVERS;
+  if (family == AF_INET) {
+    memset(&server_addr, 0, sizeof(server_addr));
+    server_addr.s_addr = htonl(0x7F000001);
+    opts.servers = &server_addr;
+    optmask |= ARES_OPT_SERVERS;
+  }
 
   // If not already overridden, set short timeouts.
   if (!(optmask & (ARES_OPT_TIMEOUTMS|ARES_OPT_TIMEOUT))) {
@@ -267,6 +281,15 @@ MockChannelOptsTest::MockChannelOptsTest(struct ares_options* givenopts,
 
   EXPECT_EQ(ARES_SUCCESS, ares_init_options(&channel_, &opts, optmask));
   EXPECT_NE(nullptr, channel_);
+
+  // For IPv6 servers, have to set up after construction.
+  if (family == AF_INET6) {
+    struct ares_addr_node addr;
+    memset(&addr, 0, sizeof(addr));
+    addr.family = AF_INET6;
+    addr.addr.addr6._S6_un._S6_u8[15] = 1;
+    EXPECT_EQ(ARES_SUCCESS, ares_set_servers(channel_, &addr));
+  }
 }
 
 MockChannelOptsTest::~MockChannelOptsTest() {
diff --git a/test/ares-test.h b/test/ares-test.h
index f723c6c5..88f79614 100644
--- a/test/ares-test.h
+++ b/test/ares-test.h
@@ -110,7 +110,7 @@ class DefaultChannelModeTest
 // Mock DNS server to allow responses to be scripted by tests.
 class MockServer {
  public:
-  MockServer(int port);
+  MockServer(int family, int port);
   ~MockServer();
 
   // Mock method indicating the processing of a particular <name, RRtype>
@@ -140,7 +140,7 @@ class MockServer {
 // Test fixture that uses a mock DNS server.
 class MockChannelOptsTest : public LibraryTest {
  public:
-  MockChannelOptsTest(struct ares_options* givenopts, int optmask);
+  MockChannelOptsTest(int family, struct ares_options* givenopts, int optmask);
   ~MockChannelOptsTest();
 
   // Process all pending work on ares-owned and mock-server-owned file descriptors.
@@ -151,9 +151,11 @@ class MockChannelOptsTest : public LibraryTest {
   ares_channel channel_;
 };
 
-class MockChannelTest : public MockChannelOptsTest {
+class MockChannelTest
+    : public MockChannelOptsTest,
+      public ::testing::WithParamInterface<int> {
  public:
-  MockChannelTest() : MockChannelOptsTest(nullptr, 0) {}
+  MockChannelTest() : MockChannelOptsTest(GetParam(), nullptr, 0) {}
 };
 
 // gMock action to set the reply for a mock server.