Fixes for test__core_timer on Linux.

src/gevent/libuv/loop.py

@@ -443,7 +443,7 @@ class loop(AbstractLoop):
             mode = libuv.UV_RUN_NOWAIT
 
         if mode == libuv.UV_RUN_DEFAULT:
-            while self._ptr:
+            while self._ptr and self._ptr.data:
                 self._prepare_ran_callbacks = False
                 ran_status = libuv.uv_run(self._ptr, libuv.UV_RUN_ONCE)
                 # Note that we run queued callbacks when the prepare watcher runs,

src/greentest/greentest/testrunner.py

@@ -343,7 +343,17 @@ def _setup_environ():
         # can't resolve package from __spec__ or __package__, falling
         # back on __name__ and __path__". I have no idea what that means, but it seems harmless
         # and is annoying.
-        os.environ['PYTHONWARNINGS'] = 'default,ignore:::site:,ignore:::importlib._bootstrap:,ignore:::importlib._bootstrap_external:'
+
+        # pkgutil on Python 2 complains about missing __init__.py
+
+        # action:message:category:module:line
+        os.environ['PYTHONWARNINGS'] = ','.join([
+            'default',
+            'ignore:::site:',
+            'ignore:::pkgutil',
+            'ignore:::importlib._bootstrap:',
+            'ignore:::importlib._bootstrap_external:',
+        ])
 
     if 'PYTHONFAULTHANDLER' not in os.environ:
         os.environ['PYTHONFAULTHANDLER'] = 'true'

src/greentest/test__core_timer.py

@@ -113,12 +113,12 @@ class TestTimerResolution(Test):
         loop = self.loop
 
 
-        for _ in range(10):
+        for _ in range(15):
             # in libuv, our signal timer fires every 300ms; depending on
             # when this runs, we could artificially get a better
             # resolution than we expect. Run it multiple times to be more sure.
             io = loop.io(fd, 1)
-            io.start(lambda events: None)
+            io.start(lambda events=None: None)
 
 
             now = perf_counter()