Update the alpha value in the echo detector.

webrtc/modules/audio_processing/echo_detector/mean_variance_estimator_unittest.cc

 
 /*
  *  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.
  */
@@ skipping 13 matching lines @@
   EXPECT_GT(test_estimator.std_deviation(), 0.f);
   // Test Clear method
   test_estimator.Clear();
   EXPECT_EQ(test_estimator.mean(), 0.f);
   EXPECT_EQ(test_estimator.std_deviation(), 0.f);
 }
 
 TEST(MeanVarianceEstimatorTests, InsertZeroes) {
   MeanVarianceEstimator test_estimator;
   // Insert the same value many times.
-  for (size_t i = 0; i < 10000; i++) {
+  for (size_t i = 0; i < 20000; i++) {
     test_estimator.Update(0.f);
   }
   EXPECT_EQ(test_estimator.mean(), 0.f);
   EXPECT_EQ(test_estimator.std_deviation(), 0.f);
 }
 
 TEST(MeanVarianceEstimatorTests, ConstantValueTest) {
   MeanVarianceEstimator test_estimator;
-  for (size_t i = 0; i < 10000; i++) {
+  for (size_t i = 0; i < 20000; i++) {
     test_estimator.Update(3.f);
   }
   // The mean should be close to three, and the standard deviation should be
   // close to zero.
   EXPECT_NEAR(3.0f, test_estimator.mean(), 0.01f);
   EXPECT_NEAR(0.0f, test_estimator.std_deviation(), 0.01f);
 }
 
 TEST(MeanVarianceEstimatorTests, AlternatingValueTest) {
   MeanVarianceEstimator test_estimator;
-  for (size_t i = 0; i < 10000; i++) {
+  for (size_t i = 0; i < 20000; i++) {
     test_estimator.Update(1.f);
     test_estimator.Update(-1.f);
   }
   // The mean should be close to zero, and the standard deviation should be
   // close to one.
   EXPECT_NEAR(0.0f, test_estimator.mean(), 0.01f);
   EXPECT_NEAR(1.0f, test_estimator.std_deviation(), 0.01f);
 }
 
 }  // namespace webrtc