Fix vlog level filtering

use_python_logger() receives a max_level argument which determines
the maximum level of traces that have to be logged. Current
implementation doesn't handle the max_level properly and this patch
fixes it.

Also, as the current unit test was only testing a case which worked,
this patch extends the coverage by testing also some corner cases.

Change-Id: Ic9718825fc8c97ae77bce773ecb42579f7527383

ovsdbapp/backend/ovs_idl/vlog.py

@@ -56,7 +56,7 @@ def use_python_logger(levels=ALL_LEVELS, max_level=None):
     """
 
     if max_level:
-        levels = levels[:-levels.index(max_level)]
+        levels = levels[:levels.index(max_level) + 1]
 
     # NOTE(twilson) Replace functions directly instead of subclassing so that
     # debug messages contain the correct function/filename/line information

ovsdbapp/tests/unit/backend/ovs_idl/test_vlog.py

@@ -38,13 +38,33 @@ class TestOvsdbVlog(base.TestCase):
             self.assertTrue(vlog.is_patched(lvl))
         self.assertFalse(vlog.is_patched(removed_level))
 
-    def test_vlog_max_level(self):
+    def _test_vlog_max_level_helper(self, max_level, patched_levels,
+                                    unpatched_levels):
         vlog.reset_logger()
-        max_level = vlog.WARN
         vlog.use_python_logger(max_level=max_level)
-        patched_levels = (vlog.CRITICAL, vlog.ERROR, vlog.WARN)
-        unpatched_levels = (vlog.INFO, vlog.DEBUG)
         for lvl in patched_levels:
             self.assertTrue(vlog.is_patched(lvl))
         for lvl in unpatched_levels:
             self.assertFalse(vlog.is_patched(lvl))
+
+    def test_vlog_max_level_WARN(self):
+        max_level = vlog.WARN
+        patched_levels = (vlog.CRITICAL, vlog.ERROR, vlog.WARN)
+        unpatched_levels = (vlog.INFO, vlog.DEBUG)
+        self._test_vlog_max_level_helper(
+            max_level, patched_levels, unpatched_levels)
+
+    def test_vlog_max_level_CRITICAL(self):
+        max_level = vlog.CRITICAL
+        patched_levels = (vlog.CRITICAL,)
+        unpatched_levels = (vlog.ERROR, vlog.WARN, vlog.INFO, vlog.DEBUG)
+        self._test_vlog_max_level_helper(
+            max_level, patched_levels, unpatched_levels)
+
+    def test_vlog_max_level_DEBUG(self):
+        max_level = vlog.DEBUG
+        patched_levels = (vlog.CRITICAL, vlog.ERROR, vlog.WARN, vlog.INFO,
+                          vlog.DEBUG)
+        unpatched_levels = ()
+        self._test_vlog_max_level_helper(
+            max_level, patched_levels, unpatched_levels)