Standalone logging tests, most of them new, and an attempt to fix the parent

msgid logic so it's a little less broken.

src/allmydata/test/test_log.py

@@ -0,0 +1,113 @@
+"""
+Tests for allmydata.util.log.
+
+Ported to Python 3.
+"""
+
+from __future__ import unicode_literals
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
+from future.utils import PY2
+if PY2:
+    from builtins import filter, map, zip, ascii, chr, hex, input, next, oct, open, pow, round, super, bytes, dict, int, list, object, range, str, max, min  # noqa: F401
+
+from twisted.trial import unittest
+from twisted.python.failure import Failure
+
+from foolscap.logging import log
+
+from allmydata.util import log as tahoe_log
+
+
+class SampleError(Exception):
+    pass
+
+
+class LoggingObject0(tahoe_log.PrefixingLogMixin):
+    pass
+
+
+class LoggingObject1(tahoe_log.PrefixingLogMixin):
+    pass
+
+
+class LoggingObject2(tahoe_log.PrefixingLogMixin):
+    pass
+
+
+class LoggingObject3(tahoe_log.PrefixingLogMixin):
+    pass
+
+
+class Log(unittest.TestCase):
+    def setUp(self):
+        self.messages = []
+
+        def msg(msg, facility, parent, *args, **kwargs):
+            self.messages.append((msg, facility, parent, args, kwargs))
+            return "msg{}".format(len(self.messages))
+
+        self.patch(log, "msg", msg)
+
+    def test_err(self):
+        """Logging with log.err() causes tests to fail."""
+        try:
+            raise SampleError("simple sample")
+        except:
+            f = Failure()
+        tahoe_log.err(format="intentional sample error",
+                      failure=f, level=tahoe_log.OPERATIONAL, umid="wO9UoQ")
+        self.flushLoggedErrors(SampleError)
+
+    def test_default_facility(self):
+        obj = LoggingObject1(facility="defaultfac")
+        obj.log("hello")
+        obj.log("world", facility="override")
+        self.assertEqual(self.messages[-2][1], "defaultfac")
+        self.assertEqual(self.messages[-1][1], "override")
+
+    def test_with_prefix(self):
+        obj = LoggingObject0("fac", prefix="pre1")
+        obj.log("hello")
+        obj.log("world")
+        self.assertEqual(self.messages[-2][0], '<LoggingObject0 #1>(pre1): hello')
+        self.assertEqual(self.messages[-1][0], '<LoggingObject0 #1>(pre1): world')
+
+    def test_no_prefix(self):
+        obj = LoggingObject2()
+        obj.log("hello")
+        obj.log("world")
+        self.assertEqual(self.messages[-2][0], '<LoggingObject2 #1>: hello')
+        self.assertEqual(self.messages[-1][0], '<LoggingObject2 #1>: world')
+
+    def test_numming(self):
+        obj = LoggingObject3()
+        obj2 = LoggingObject3()
+        obj.log("hello")
+        obj2.log("world")
+        self.assertEqual(self.messages[-2][0], '<LoggingObject3 #1>: hello')
+        self.assertEqual(self.messages[-1][0], '<LoggingObject3 #2>: world')
+
+    def test_parent_id(self):
+        obj = LoggingObject1()
+        result = obj.log("zero")
+        self.assertEqual(result, "msg1")
+        obj.log("one", parent="par1")
+        obj.log("two", parent="par2")
+        obj.log("three")
+        obj.log("four")
+        self.assertEqual([m[2] for m in self.messages],
+                         [None, "par1", "par2", "msg1", "msg1"])
+
+    def test_grandparent_id(self):
+        obj = LoggingObject1(grandparentmsgid="grand")
+        result = obj.log("zero")
+        self.assertEqual(result, "msg1")
+        obj.log("one", parent="par1")
+        obj.log("two", parent="par2")
+        obj.log("three")
+        obj.log("four")
+        self.assertEqual([m[2] for m in self.messages],
+                         ["grand", "par1", "par2", "msg1", "msg1"])

src/allmydata/util/log.py

@@ -36,8 +36,8 @@ class LogMixin(object):
     def log(self, msg, facility=None, parent=None, *args, **kwargs):
         if facility is None:
             facility = self._facility
-        pmsgid = None
-        if parent is None:
+        pmsgid = parent
+        if pmsgid is None:
             pmsgid = self._parentmsgid
             if pmsgid is None:
                 pmsgid = self._grandparentmsgid