diff --git a/services/surfaceflinger/tests/unittests/DisplayTransactionTest.cpp b/services/surfaceflinger/tests/unittests/DisplayTransactionTest.cpp
index 2425862..f04221c 100644
--- a/services/surfaceflinger/tests/unittests/DisplayTransactionTest.cpp
+++ b/services/surfaceflinger/tests/unittests/DisplayTransactionTest.cpp
@@ -165,36 +165,39 @@
     return displayDevice;
 }
 
-bool DisplayTransactionTest::hasPhysicalHwcDisplay(HWDisplayId hwcDisplayId) {
-    return mFlinger.mutableHwcPhysicalDisplayIdMap().count(hwcDisplayId) == 1;
+bool DisplayTransactionTest::hasPhysicalHwcDisplay(HWDisplayId hwcDisplayId) const {
+    return mFlinger.hwcPhysicalDisplayIdMap().count(hwcDisplayId) == 1;
 }
 
-bool DisplayTransactionTest::hasTransactionFlagSet(int flag) {
-    return mFlinger.mutableTransactionFlags() & flag;
+bool DisplayTransactionTest::hasTransactionFlagSet(int32_t flag) const {
+    return mFlinger.transactionFlags() & flag;
 }
 
-bool DisplayTransactionTest::hasDisplayDevice(sp<IBinder> displayToken) {
-    return mFlinger.mutableDisplays().count(displayToken) == 1;
+bool DisplayTransactionTest::hasDisplayDevice(const sp<IBinder>& displayToken) const {
+    return mFlinger.displays().contains(displayToken);
 }
 
-sp<DisplayDevice> DisplayTransactionTest::getDisplayDevice(sp<IBinder> displayToken) {
-    return mFlinger.mutableDisplays()[displayToken];
+const DisplayDevice& DisplayTransactionTest::getDisplayDevice(
+        const sp<IBinder>& displayToken) const {
+    return *mFlinger.displays().get(displayToken)->get();
 }
 
-bool DisplayTransactionTest::hasCurrentDisplayState(sp<IBinder> displayToken) {
-    return mFlinger.mutableCurrentState().displays.indexOfKey(displayToken) >= 0;
+bool DisplayTransactionTest::hasCurrentDisplayState(const sp<IBinder>& displayToken) const {
+    return mFlinger.currentState().displays.indexOfKey(displayToken) >= 0;
 }
 
-const DisplayDeviceState& DisplayTransactionTest::getCurrentDisplayState(sp<IBinder> displayToken) {
-    return mFlinger.mutableCurrentState().displays.valueFor(displayToken);
+const DisplayDeviceState& DisplayTransactionTest::getCurrentDisplayState(
+        const sp<IBinder>& displayToken) const {
+    return mFlinger.currentState().displays.valueFor(displayToken);
 }
 
-bool DisplayTransactionTest::hasDrawingDisplayState(sp<IBinder> displayToken) {
-    return mFlinger.mutableDrawingState().displays.indexOfKey(displayToken) >= 0;
+bool DisplayTransactionTest::hasDrawingDisplayState(const sp<IBinder>& displayToken) const {
+    return mFlinger.drawingState().displays.indexOfKey(displayToken) >= 0;
 }
 
-const DisplayDeviceState& DisplayTransactionTest::getDrawingDisplayState(sp<IBinder> displayToken) {
-    return mFlinger.mutableDrawingState().displays.valueFor(displayToken);
+const DisplayDeviceState& DisplayTransactionTest::getDrawingDisplayState(
+        const sp<IBinder>& displayToken) const {
+    return mFlinger.drawingState().displays.valueFor(displayToken);
 }
 
 } // namespace android
diff --git a/services/surfaceflinger/tests/unittests/DisplayTransactionTestHelpers.h b/services/surfaceflinger/tests/unittests/DisplayTransactionTestHelpers.h
index 565c244..f5235ce 100644
--- a/services/surfaceflinger/tests/unittests/DisplayTransactionTestHelpers.h
+++ b/services/surfaceflinger/tests/unittests/DisplayTransactionTestHelpers.h
@@ -95,14 +95,17 @@
     // --------------------------------------------------------------------
     // Postcondition helpers
 
-    bool hasPhysicalHwcDisplay(hal::HWDisplayId hwcDisplayId);
-    bool hasTransactionFlagSet(int flag);
-    bool hasDisplayDevice(sp<IBinder> displayToken);
-    sp<DisplayDevice> getDisplayDevice(sp<IBinder> displayToken);
-    bool hasCurrentDisplayState(sp<IBinder> displayToken);
-    const DisplayDeviceState& getCurrentDisplayState(sp<IBinder> displayToken);
-    bool hasDrawingDisplayState(sp<IBinder> displayToken);
-    const DisplayDeviceState& getDrawingDisplayState(sp<IBinder> displayToken);
+    bool hasPhysicalHwcDisplay(hal::HWDisplayId) const;
+    bool hasTransactionFlagSet(int32_t flag) const;
+
+    bool hasDisplayDevice(const sp<IBinder>& displayToken) const;
+    const DisplayDevice& getDisplayDevice(const sp<IBinder>& displayToken) const;
+
+    bool hasCurrentDisplayState(const sp<IBinder>& displayToken) const;
+    const DisplayDeviceState& getCurrentDisplayState(const sp<IBinder>& displayToken) const;
+
+    bool hasDrawingDisplayState(const sp<IBinder>& displayToken) const;
+    const DisplayDeviceState& getDrawingDisplayState(const sp<IBinder>& displayToken) const;
 
     // --------------------------------------------------------------------
     // Test instances
diff --git a/services/surfaceflinger/tests/unittests/SurfaceFlinger_DisplayTransactionCommitTest.cpp b/services/surfaceflinger/tests/unittests/SurfaceFlinger_DisplayTransactionCommitTest.cpp
index 6959ee3..9ac2907 100644
--- a/services/surfaceflinger/tests/unittests/SurfaceFlinger_DisplayTransactionCommitTest.cpp
+++ b/services/surfaceflinger/tests/unittests/SurfaceFlinger_DisplayTransactionCommitTest.cpp
@@ -107,9 +107,10 @@
 void DisplayTransactionCommitTest::verifyDisplayIsConnected(const sp<IBinder>& displayToken) {
     // The display device should have been set up in the list of displays.
     ASSERT_TRUE(hasDisplayDevice(displayToken));
-    const auto& device = getDisplayDevice(displayToken);
-    EXPECT_EQ(static_cast<bool>(Case::Display::SECURE), device->isSecure());
-    EXPECT_EQ(static_cast<bool>(Case::Display::PRIMARY), device->isPrimary());
+    const auto& display = getDisplayDevice(displayToken);
+
+    EXPECT_EQ(static_cast<bool>(Case::Display::SECURE), display.isSecure());
+    EXPECT_EQ(static_cast<bool>(Case::Display::PRIMARY), display.isPrimary());
 
     std::optional<DisplayDeviceState::Physical> expectedPhysical;
     if (const auto connectionType = Case::Display::CONNECTION_TYPE::value) {
@@ -143,10 +144,11 @@
     // SF should have a display token.
     const auto displayId = Case::Display::DISPLAY_ID::get();
     ASSERT_TRUE(PhysicalDisplayId::tryCast(displayId));
-    ASSERT_EQ(mFlinger.mutablePhysicalDisplayTokens().count(displayId), 1);
-    auto& displayToken = mFlinger.mutablePhysicalDisplayTokens()[displayId];
 
-    verifyDisplayIsConnected<Case>(displayToken);
+    const auto displayTokenOpt = mFlinger.mutablePhysicalDisplayTokens().get(displayId);
+    ASSERT_TRUE(displayTokenOpt);
+
+    verifyDisplayIsConnected<Case>(displayTokenOpt->get());
 }
 
 void DisplayTransactionCommitTest::verifyDisplayIsNotConnected(const sp<IBinder>& displayToken) {
@@ -248,9 +250,9 @@
     // SF should not have a display token.
     const auto displayId = Case::Display::DISPLAY_ID::get();
     ASSERT_TRUE(PhysicalDisplayId::tryCast(displayId));
-    ASSERT_TRUE(mFlinger.mutablePhysicalDisplayTokens().count(displayId) == 0);
+    ASSERT_FALSE(mFlinger.mutablePhysicalDisplayTokens().contains(displayId));
 
-    // The existing token should have been removed
+    // The existing token should have been removed.
     verifyDisplayIsNotConnected(existing.token());
 }
 
@@ -330,7 +332,7 @@
                 // SF should not have a display token.
                 const auto displayId = Case::Display::DISPLAY_ID::get();
                 ASSERT_TRUE(PhysicalDisplayId::tryCast(displayId));
-                ASSERT_TRUE(mFlinger.mutablePhysicalDisplayTokens().count(displayId) == 0);
+                ASSERT_FALSE(mFlinger.mutablePhysicalDisplayTokens().contains(displayId));
             }(),
             testing::KilledBySignal(SIGABRT), "Primary display cannot be disconnected.");
 }
@@ -369,15 +371,16 @@
                 // --------------------------------------------------------------------
                 // Postconditions
 
-                // The existing token should have been removed
+                // The existing token should have been removed.
                 verifyDisplayIsNotConnected(existing.token());
                 const auto displayId = Case::Display::DISPLAY_ID::get();
                 ASSERT_TRUE(PhysicalDisplayId::tryCast(displayId));
-                ASSERT_TRUE(mFlinger.mutablePhysicalDisplayTokens().count(displayId) == 1);
-                EXPECT_NE(existing.token(), mFlinger.mutablePhysicalDisplayTokens()[displayId]);
 
-                // A new display should be connected in its place
+                const auto displayTokenOpt = mFlinger.mutablePhysicalDisplayTokens().get(displayId);
+                ASSERT_TRUE(displayTokenOpt);
+                EXPECT_NE(existing.token(), displayTokenOpt->get());
 
+                // A new display should be connected in its place.
                 verifyPhysicalDisplayIsConnected<Case>();
 
                 // --------------------------------------------------------------------
diff --git a/services/surfaceflinger/tests/unittests/SurfaceFlinger_SetPowerModeInternalTest.cpp b/services/surfaceflinger/tests/unittests/SurfaceFlinger_SetPowerModeInternalTest.cpp
index 7948e60..583cf5f 100644
--- a/services/surfaceflinger/tests/unittests/SurfaceFlinger_SetPowerModeInternalTest.cpp
+++ b/services/surfaceflinger/tests/unittests/SurfaceFlinger_SetPowerModeInternalTest.cpp
@@ -406,7 +406,7 @@
     display.inject();
 
     // The display is set to PowerMode::ON
-    getDisplayDevice(display.token())->setPowerMode(PowerMode::ON);
+    display.mutableDisplayDevice()->setPowerMode(PowerMode::ON);
 
     // --------------------------------------------------------------------
     // Invocation
diff --git a/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h b/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h
index 866d9eb..f1a69fb 100644
--- a/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h
+++ b/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h
@@ -517,6 +517,12 @@
      * post-conditions.
      */
 
+    const auto& displays() const { return mFlinger->mDisplays; }
+    const auto& currentState() const { return mFlinger->mCurrentState; }
+    const auto& drawingState() const { return mFlinger->mDrawingState; }
+    const auto& transactionFlags() const { return mFlinger->mTransactionFlags; }
+    const auto& hwcPhysicalDisplayIdMap() const { return getHwComposer().mPhysicalDisplayIdMap; }
+
     auto& mutableHasWideColorDisplay() { return SurfaceFlinger::hasWideColorDisplay; }
 
     auto& mutableCurrentState() { return mFlinger->mCurrentState; }
@@ -755,7 +761,9 @@
             return mFlinger.mutableCurrentState().displays.valueFor(mDisplayToken);
         }
 
-        auto& mutableDisplayDevice() { return mFlinger.mutableDisplays()[mDisplayToken]; }
+        const sp<DisplayDevice>& mutableDisplayDevice() {
+            return mFlinger.mutableDisplays().get(mDisplayToken)->get();
+        }
 
         // If `configs` is nullptr, the injector creates RefreshRateConfigs from the `modes`.
         // Otherwise, it uses `configs`, which the caller must create using the same `modes`.
@@ -862,12 +870,14 @@
             if (!display->isVirtual()) {
                 display->setActiveMode(activeModeId);
             }
-            mFlinger.mutableDisplays().emplace(mDisplayToken, display);
+            mFlinger.mutableDisplays().emplace_or_replace(mDisplayToken, display);
+
             mFlinger.mutableCurrentState().displays.add(mDisplayToken, state);
             mFlinger.mutableDrawingState().displays.add(mDisplayToken, state);
 
             if (const auto& physical = state.physical) {
-                mFlinger.mutablePhysicalDisplayTokens()[physical->id] = mDisplayToken;
+                mFlinger.mutablePhysicalDisplayTokens().emplace_or_replace(physical->id,
+                                                                           mDisplayToken);
             }
 
             return display;