Skip UnixRouterTests when werkzeug is not installed.

Refs #1639.

Author: aaugustin

tests/asyncio/test_router.py

@@ -186,6 +186,7 @@ async def handler(self, connection):
 
 
 @unittest.skipUnless(hasattr(socket, "AF_UNIX"), "this test requires Unix sockets")
+@unittest.skipUnless("werkzeug" in sys.modules, "werkzeug not installed")
 class UnixRouterTests(EvalShellMixin, unittest.IsolatedAsyncioTestCase):
  async def test_router_supports_unix_sockets(self):
  """Router supports Unix sockets."""

tests/sync/test_router.py

@@ -162,6 +162,7 @@ def handler(self, connection):
 
 
 @unittest.skipUnless(hasattr(socket, "AF_UNIX"), "this test requires Unix sockets")
+@unittest.skipUnless("werkzeug" in sys.modules, "werkzeug not installed")
 class UnixRouterTests(EvalShellMixin, unittest.IsolatedAsyncioTestCase):
  def test_router_supports_unix_sockets(self):
  """Router supports Unix sockets."""