TestEtcHosts round-robin failures also seen on appveyor with the system...

TestEtcHosts round-robin failures also seen on appveyor with the system resolver---because we're not using the local system hosts file.

src/greentest/greentest/__init__.py

@@ -52,6 +52,10 @@ from greentest.sysinfo import RUNNING_ON_TRAVIS
 from greentest.sysinfo import RUNNING_ON_APPVEYOR
 from greentest.sysinfo import RUNNING_ON_CI
 
+from greentest.sysinfo import RESOLVER_NOT_SYSTEM
+from greentest.sysinfo import RESOLVER_DNSPYTHON
+from greentest.sysinfo import RESOLVER_ARES
+
 from greentest.sysinfo import EXPECT_POOR_TIMER_RESOLUTION
 
 from greentest.sysinfo import CONN_ABORTED_ERRORS

src/greentest/test__socket_dns.py

@@ -25,7 +25,6 @@ if getattr(resolver, 'pool', None) is not None:
 
 from greentest.sysinfo import RESOLVER_NOT_SYSTEM
 from greentest.sysinfo import RESOLVER_DNSPYTHON
-from greentest.sysinfo import RESOLVER_ARES
 from greentest.sysinfo import PY2
 import greentest.timing
 
@@ -446,8 +445,12 @@ class SanitizedHostsFile(HostsFile):
                 continue
             yield name, addr
 
-@greentest.skipIf(greentest.RUNNING_ON_TRAVIS and RESOLVER_ARES,
-                  "This sometimes randomly fails on Travis with ares, beginning Feb 13, 2018")
+@greentest.skipIf(greentest.RUNNING_ON_CI,
+                  "This sometimes randomly fails on Travis with ares and on appveyor, beginning Feb 13, 2018")
+# Probably due to round-robin DNS,
+# since this is not actually the system's etc hosts file.
+# TODO: Rethink this. We need something reliable. Go back to using
+# the system's etc hosts?
 class TestEtcHosts(TestCase):
 
     MAX_HOSTS = os.getenv('GEVENTTEST_MAX_ETC_HOSTS', 10)