diff --git a/services/surfaceflinger/tests/unittests/SchedulerTest.cpp b/services/surfaceflinger/tests/unittests/SchedulerTest.cpp
index 38e503f..8ad8ea4 100644
--- a/services/surfaceflinger/tests/unittests/SchedulerTest.cpp
+++ b/services/surfaceflinger/tests/unittests/SchedulerTest.cpp
@@ -51,9 +51,18 @@
 
     SchedulerTest();
 
-    const scheduler::RefreshRateConfigs
-            mConfigs{{DisplayMode::Builder(0).setVsyncPeriod(16'666'667).setGroup(0).build()},
-                     DisplayModeId(0)};
+    const DisplayModePtr mode60 = DisplayMode::Builder(0)
+                                          .setId(DisplayModeId(0))
+                                          .setVsyncPeriod(Fps(60.f).getPeriodNsecs())
+                                          .setGroup(0)
+                                          .build();
+    const DisplayModePtr mode120 = DisplayMode::Builder(1)
+                                           .setId(DisplayModeId(1))
+                                           .setVsyncPeriod(Fps(120.f).getPeriodNsecs())
+                                           .setGroup(0)
+                                           .build();
+
+    scheduler::RefreshRateConfigs mConfigs{{mode60}, mode60->getId()};
 
     mock::SchedulerCallback mSchedulerCallback;
 
@@ -149,15 +158,14 @@
     EXPECT_EQ(kEventConnections, mScheduler->getEventThreadConnectionCount(mConnectionHandle));
 }
 
-TEST_F(SchedulerTest, noLayerHistory) {
-    // Layer history should not be created if there is a single config.
-    ASSERT_FALSE(mScheduler->hasLayerHistory());
-
+TEST_F(SchedulerTest, chooseRefreshRateForContentIsNoopWhenModeSwitchingIsNotSupported) {
+    // The layer is registered at creation time and deregistered at destruction time.
     sp<mock::MockLayer> layer = sp<mock::MockLayer>::make(mFlinger.flinger());
 
-    // Content detection should be no-op.
-    mScheduler->registerLayer(layer.get());
+    // recordLayerHistory should be a noop
+    ASSERT_EQ(static_cast<size_t>(0), mScheduler->getNumActiveLayers());
     mScheduler->recordLayerHistory(layer.get(), 0, LayerHistory::LayerUpdateType::Buffer);
+    ASSERT_EQ(static_cast<size_t>(0), mScheduler->getNumActiveLayers());
 
     constexpr bool kPowerStateNormal = true;
     mScheduler->setDisplayPowerState(kPowerStateNormal);
@@ -169,6 +177,18 @@
     mScheduler->chooseRefreshRateForContent();
 }
 
+TEST_F(SchedulerTest, updateDisplayModes) {
+    ASSERT_EQ(static_cast<size_t>(0), mScheduler->layerHistorySize());
+    sp<mock::MockLayer> layer = sp<mock::MockLayer>::make(mFlinger.flinger());
+    ASSERT_EQ(static_cast<size_t>(1), mScheduler->layerHistorySize());
+
+    mConfigs.updateDisplayModes({mode60, mode120}, /* activeMode */ mode60->getId());
+
+    ASSERT_EQ(static_cast<size_t>(0), mScheduler->getNumActiveLayers());
+    mScheduler->recordLayerHistory(layer.get(), 0, LayerHistory::LayerUpdateType::Buffer);
+    ASSERT_EQ(static_cast<size_t>(1), mScheduler->getNumActiveLayers());
+}
+
 TEST_F(SchedulerTest, testDispatchCachedReportedMode) {
     // If the optional fields are cleared, the function should return before
     // onModeChange is called.
diff --git a/services/surfaceflinger/tests/unittests/TestableScheduler.h b/services/surfaceflinger/tests/unittests/TestableScheduler.h
index 3f9dd01..41fd6e3 100644
--- a/services/surfaceflinger/tests/unittests/TestableScheduler.h
+++ b/services/surfaceflinger/tests/unittests/TestableScheduler.h
@@ -64,6 +64,11 @@
         return mutableLayerHistory()->mLayerInfos.size();
     }
 
+    size_t getNumActiveLayers() NO_THREAD_SAFETY_ANALYSIS {
+        if (!mLayerHistory) return 0;
+        return mutableLayerHistory()->mActiveLayersEnd;
+    }
+
     void replaceTouchTimer(int64_t millis) {
         if (mTouchTimer) {
             mTouchTimer.reset();