Docserver: greatly improve the error logging by (a) preserving the stack traces in Futures,

(b) actually logging the stack trace, and (c) respecting DeadlineExceededErrors.

BUG=167432

Review URL: https://codereview.chromium.org/14333015

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@196309 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 74 insertions, 0 deletions

diff --git a/chrome/common/extensions/docs/server2/future_test.py b/chrome/common/extensions/docs/server2/future_test.py
new file mode 100755
index 0000000..3b31a0c
--- /dev/null
+++ b/chrome/common/extensions/docs/server2/future_test.py
@@ -0,0 +1,74 @@
+#!/usr/bin/env python
+# Copyright 2013 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import traceback
+import unittest
+
+from future import Future
+
+class FutureTest(unittest.TestCase):
+  def testNoValueOrDelegate(self):
+    self.assertRaises(ValueError, Future)
+
+  def testValue(self):
+    future = Future(value=42)
+    self.assertEqual(42, future.Get())
+    self.assertEqual(42, future.Get())
+
+  def testDelegateValue(self):
+    assertFalse = self.assertFalse
+    class delegate(object):
+      def __init__(self):
+        self._get_called = False
+      def Get(self):
+        assertFalse(self._get_called)
+        self._get_called = True
+        return 42
+
+    future = Future(delegate=delegate())
+    self.assertEqual(42, future.Get())
+    self.assertEqual(42, future.Get())
+
+  def testErrorThrowingDelegate(self):
+    class FunkyException(Exception):
+      pass
+
+    # Set up a chain of functions to test the stack trace.
+    def qux():
+      raise FunkyException()
+    def baz():
+      return qux()
+    def bar():
+      return baz()
+    def foo():
+      return bar()
+    chain = [foo, bar, baz, qux]
+
+    assertFalse = self.assertFalse
+    class delegate(object):
+      def __init__(self):
+        self._get_called = False
+      def Get(self):
+        assertFalse(self._get_called)
+        self._get_called = True
+        return foo()
+
+    fail = self.fail
+    assertTrue = self.assertTrue
+    def assert_raises_full_stack(future, err):
+      try:
+        future.Get()
+        fail('Did not raise %s' % err)
+      except Exception as e:
+        assertTrue(isinstance(e, err))
+        stack = traceback.format_exc()
+        assertTrue(all(stack.find(fn.__name__) != -1 for fn in chain))
+
+    future = Future(delegate=delegate())
+    assert_raises_full_stack(future, FunkyException)
+    assert_raises_full_stack(future, FunkyException)
+
+if __name__ == '__main__':
+  unittest.main()