From b378a22544b91c0a3c586156db90d76063cf9717 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Erik=20Spr=C3=A5ng?= <sprang@webrtc.org>
Date: Mon, 2 Oct 2017 13:25:38 +0200
Subject: [PATCH] Fix ALR field trial parsing
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Bug: chromium:770429
Change-Id: Ic869e74ec7086f5a2cb3968c0d2335fd7df7f618
Reviewed-on: https://webrtc-review.googlesource.com/5483
Reviewed-by: Philip Eliasson <philipel@webrtc.org>
Commit-Queue: Erik Språng <sprang@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#20076}
---
 modules/pacing/BUILD.gn                 |  1 +
 modules/pacing/alr_detector.cc          |  5 +++--
 modules/pacing/alr_detector_unittest.cc | 25 +++++++++++++++++++++++++
 3 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/modules/pacing/BUILD.gn b/modules/pacing/BUILD.gn
index f72d3f990f..fd350a4026 100644
--- a/modules/pacing/BUILD.gn
+++ b/modules/pacing/BUILD.gn
@@ -65,6 +65,7 @@ if (rtc_include_tests) {
       "../../rtc_base:rtc_base_approved",
       "../../rtc_base:rtc_base_tests_utils",
       "../../system_wrappers:system_wrappers",
+      "../../test:field_trial",
       "../../test:test_support",
       "../rtp_rtcp",
       "../rtp_rtcp:mock_rtp_rtcp",
diff --git a/modules/pacing/alr_detector.cc b/modules/pacing/alr_detector.cc
index 3b60a3793a..1c29e0a012 100644
--- a/modules/pacing/alr_detector.cc
+++ b/modules/pacing/alr_detector.cc
@@ -83,8 +83,9 @@ AlrDetector::ParseAlrSettingsFromFieldTrial(const char* experiment_name) {
   std::string group_name = field_trial::FindFullName(experiment_name);
 
   const std::string kIgnoredSuffix = "_Dogfood";
-  if (group_name.rfind(kIgnoredSuffix) ==
-      group_name.length() - kIgnoredSuffix.length()) {
+  std::string::size_type suffix_pos = group_name.rfind(kIgnoredSuffix);
+  if (suffix_pos != std::string::npos &&
+      suffix_pos == group_name.length() - kIgnoredSuffix.length()) {
     group_name.resize(group_name.length() - kIgnoredSuffix.length());
   }
 
diff --git a/modules/pacing/alr_detector_unittest.cc b/modules/pacing/alr_detector_unittest.cc
index 891b4ef0c1..927015615c 100644
--- a/modules/pacing/alr_detector_unittest.cc
+++ b/modules/pacing/alr_detector_unittest.cc
@@ -10,6 +10,7 @@
 
 #include "modules/pacing/alr_detector.h"
 
+#include "test/field_trial.h"
 #include "test/gtest.h"
 
 namespace {
@@ -142,4 +143,28 @@ TEST_F(AlrDetectorTest, BandwidthEstimateChanges) {
   EXPECT_FALSE(alr_detector_.GetApplicationLimitedRegionStartTime());
 }
 
+TEST_F(AlrDetectorTest, ParseControlFieldTrial) {
+  webrtc::test::ScopedFieldTrials field_trial(
+      "WebRTC-ProbingScreenshareBwe/Control/");
+  rtc::Optional<AlrDetector::AlrExperimentSettings> parsed_params =
+      AlrDetector::ParseAlrSettingsFromFieldTrial(
+          "WebRTC-ProbingScreenshareBwe");
+  EXPECT_FALSE(static_cast<bool>(parsed_params));
+}
+
+TEST_F(AlrDetectorTest, ParseActiveFieldTrial) {
+  webrtc::test::ScopedFieldTrials field_trial(
+      "WebRTC-ProbingScreenshareBwe/1.1,2875,85,20,-20,1/");
+  rtc::Optional<AlrDetector::AlrExperimentSettings> parsed_params =
+      AlrDetector::ParseAlrSettingsFromFieldTrial(
+          "WebRTC-ProbingScreenshareBwe");
+  ASSERT_TRUE(static_cast<bool>(parsed_params));
+  EXPECT_EQ(1.1f, parsed_params->pacing_factor);
+  EXPECT_EQ(2875, parsed_params->max_paced_queue_time);
+  EXPECT_EQ(85, parsed_params->alr_bandwidth_usage_percent);
+  EXPECT_EQ(20, parsed_params->alr_start_budget_level_percent);
+  EXPECT_EQ(-20, parsed_params->alr_stop_budget_level_percent);
+  EXPECT_EQ(1, parsed_params->group_id);
+}
+
 }  // namespace webrtc