Python event log analyzer tool: fix of indexing issue.

Test added to ensure it doesn't happen again.

NOTRY=True

Review-Url: https://codereview.webrtc.org/2316573003
Cr-Commit-Position: refs/heads/master@{#14121}

webrtc/tools/py_event_log_analyzer/misc_test.py

@@ -22,7 +22,6 @@ import misc
 
 
 class TestMisc(unittest.TestCase):
-
   def testUnwrapMod3(self):
     data = [0, 1, 2, 0, -1, -2, -3, -4]
     unwrapped_3 = misc.unwrap(data, 3)

webrtc/tools/py_event_log_analyzer/rtp_analyzer.py

@@ -280,7 +280,7 @@ def calculate_delay(start, stop, step, points):
   masked array, in which time points with no value are masked.
 
   """
-  grouped_delays = [[] for _ in numpy.arange(start, stop, step)]
+  grouped_delays = [[] for _ in numpy.arange(start, stop + step, step)]
   rounded_value_index = lambda x: int((x - start) / step)
   for point in points:
     grouped_delays[rounded_value_index(point.real_send_time_ms)

webrtc/tools/py_event_log_analyzer/rtp_analyzer_test.py

@@ -0,0 +1,62 @@
+#!/usr/bin/env python
+#  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
+#
+#  Use of this source code is governed by a BSD-style license
+#  that can be found in the LICENSE file in the root of the source
+#  tree. An additional intellectual property rights grant can be found
+#  in the file PATENTS.  All contributing project authors may
+#  be found in the AUTHORS file in the root of the source tree.
+
+"""Run the tests with
+
+      python rtp_analyzer_test.py
+or
+      python3 rtp_analyzer_test.py
+"""
+
+import collections
+import unittest
+
+missing_numpy = False
+try:
+  import numpy
+  import rtp_analyzer
+except ImportError:
+  missing_numpy = True
+
+FakePoint = collections.namedtuple("FakePoint",
+                                   ["real_send_time_ms", "absdelay"])
+
+
+class TestDelay(unittest.TestCase):
+  def assertMaskEqual(self, masked_array, data, mask):
+    self.assertEqual(list(masked_array.data), data)
+
+    if isinstance(masked_array.mask, numpy.bool_):
+      array_mask = masked_array.mask
+    else:
+      array_mask = list(masked_array.mask)
+    self.assertEqual(array_mask, mask)
+
+  def testCalculateDelaySimple(self):
+    points = [FakePoint(0, 0), FakePoint(1, 0)]
+    mask = rtp_analyzer.calculate_delay(0, 1, 1, points)
+    self.assertMaskEqual(mask, [0, 0], False)
+
+  def testCalculateDelayMissing(self):
+    points = [FakePoint(0, 0), FakePoint(2, 0)]
+    mask = rtp_analyzer.calculate_delay(0, 2, 1, points)
+    self.assertMaskEqual(mask, [0, -1, 0], [False, True, False])
+
+  def testCalculateDelayBorders(self):
+    points = [FakePoint(0, 0), FakePoint(2, 0)]
+    mask = rtp_analyzer.calculate_delay(0, 3, 2, points)
+    self.assertMaskEqual(mask, [0, 0, -1], [False, False, True])
+
+
+if __name__ == "__main__":
+  if missing_numpy:
+    # pylint: disable=superfluous-parens
+    print("Missing numpy, skipping test.")
+  else:
+    unittest.main()