Fix coverage problems

.coveragerc

@@ -20,7 +20,10 @@ exclude_lines =
     raise TypeError
     raise NotImplementedError
     warnings.warn
+    logger.debug
+    logger.info
     logger.warning
+    logger.error
     return NotHandled
 
     # Don't complain if non-runnable code isn't run:

src/drf_yasg/generators.py

@@ -97,6 +97,8 @@ class EndpointEnumerator(_EndpointEnumerator):
                     namespace="%s:%s" % (namespace, pattern.namespace) if namespace else pattern.namespace
                 )
                 api_endpoints.extend(nested_endpoints)
+            else:
+                logger.warning("unknown pattern type {}".format(type(pattern)))
 
         api_endpoints = sorted(api_endpoints, key=endpoint_ordering)