Reimplemeted "Test and fix for huge bwe drop after alr state"

webrtc/modules/pacing/alr_detector_unittest.cc

Index: webrtc/modules/pacing/alr_detector_unittest.cc
diff --git a/webrtc/modules/pacing/alr_detector_unittest.cc b/webrtc/modules/pacing/alr_detector_unittest.cc
index e1a78103dfa235b8333b1529af6fbe59267b43b9..dab9477e2eb2e9de424abcce15806aab5db654c8 100644
--- a/webrtc/modules/pacing/alr_detector_unittest.cc
+++ b/webrtc/modules/pacing/alr_detector_unittest.cc
@@ -10,11 +10,13 @@
 
 #include "webrtc/modules/pacing/alr_detector.h"
 
+#include "webrtc/rtc_base/fakeclock.h"
 #include "webrtc/test/gtest.h"
 
 namespace {
 
 constexpr int kEstimatedBitrateBps = 300000;
+// constexpr int64_t kAlrEndedTimeMs = 1234;
 
 }  // namespace
 
@@ -86,7 +88,7 @@ TEST_F(AlrDetectorTest, AlrDetection) {
 
   // Verify that we ALR starts when bitrate drops below 20%.
   SimulateOutgoingTrafficIn(&alr_detector_)
-      .ForTimeMs(1000)
+      .ForTimeMs(1500)
       .AtPercentOfEstimatedBitrate(20);
   EXPECT_TRUE(alr_detector_.GetApplicationLimitedRegionStartTime());
 
@@ -109,7 +111,7 @@ TEST_F(AlrDetectorTest, ShortSpike) {
 
   // Verify that we stay in ALR region even after a short bitrate spike.
   SimulateOutgoingTrafficIn(&alr_detector_)
-      .ForTimeMs(200)
+      .ForTimeMs(100)
       .AtPercentOfEstimatedBitrate(150);
   EXPECT_TRUE(alr_detector_.GetApplicationLimitedRegionStartTime());
 
@@ -142,4 +144,23 @@ TEST_F(AlrDetectorTest, BandwidthEstimateChanges) {
   EXPECT_FALSE(alr_detector_.GetApplicationLimitedRegionStartTime());
 }
 
+TEST(AlrStateTest, NotStateChangeWhenNoStartTimeProvided) {
+  AlrState alr_state;
+  EXPECT_EQ(alr_state.ChangeWhenAlrStartTimeIs(rtc::Optional<int64_t>()),
+            AlrState::Change::kNoChange);
+}
+
+TEST(AlrStateTest, StateChangeToAlr) {
+  AlrState alr_state;
+  EXPECT_EQ(alr_state.ChangeWhenAlrStartTimeIs(rtc::Optional<int64_t>(10)),
+            AlrState::Change::kStarted);
+}
+
+TEST(AlrStateTest, StateChangeToNoAlr) {
+  AlrState alr_state;
+  alr_state.ChangeWhenAlrStartTimeIs(rtc::Optional<int64_t>(10));
+  EXPECT_EQ(alr_state.ChangeWhenAlrStartTimeIs(rtc::Optional<int64_t>()),
+            AlrState::Change::kEnded);
+}
+
 }  // namespace webrtc