diff --git a/services/inputflinger/tests/InputReader_test.cpp b/services/inputflinger/tests/InputReader_test.cpp
index 54cf15d..9f33d23 100644
--- a/services/inputflinger/tests/InputReader_test.cpp
+++ b/services/inputflinger/tests/InputReader_test.cpp
@@ -20,6 +20,7 @@
 #include <InputReader.h>
 #include <InputReaderBase.h>
 #include <InputReaderFactory.h>
+#include <JoystickInputMapper.h>
 #include <KeyboardInputMapper.h>
 #include <MultiTouchInputMapper.h>
 #include <PeripheralController.h>
@@ -8251,6 +8252,25 @@
     ASSERT_EQ(DISPLAY_ID, args.displayId);
 }
 
+TEST_F(MultiTouchInputMapperTest, Configure_AssignsDisplayUniqueId) {
+    addConfigurationProperty("touch.deviceType", "touchScreen");
+    prepareAxes(POSITION);
+    MultiTouchInputMapper& mapper = addMapperAndConfigure<MultiTouchInputMapper>();
+
+    mFakePolicy->addInputUniqueIdAssociation(DEVICE_LOCATION, VIRTUAL_DISPLAY_UNIQUE_ID);
+
+    prepareDisplay(DISPLAY_ORIENTATION_0);
+    prepareVirtualDisplay(DISPLAY_ORIENTATION_0);
+
+    // Send a touch event
+    processPosition(mapper, 100, 100);
+    processSync(mapper);
+
+    NotifyMotionArgs args;
+    ASSERT_NO_FATAL_FAILURE(mFakeListener->assertNotifyMotionWasCalled(&args));
+    ASSERT_EQ(VIRTUAL_DISPLAY_ID, args.displayId);
+}
+
 TEST_F(MultiTouchInputMapperTest, Process_Pointer_ShouldHandleDisplayId) {
     // Setup for second display.
     std::shared_ptr<FakePointerController> fakePointerController =
@@ -9260,6 +9280,67 @@
     ASSERT_EQ(AINPUT_SOURCE_TOUCHPAD, mapper.getSources());
 }
 
+// --- JoystickInputMapperTest ---
+
+class JoystickInputMapperTest : public InputMapperTest {
+protected:
+    static const int32_t RAW_X_MIN;
+    static const int32_t RAW_X_MAX;
+    static const int32_t RAW_Y_MIN;
+    static const int32_t RAW_Y_MAX;
+
+    void SetUp() override {
+        InputMapperTest::SetUp(InputDeviceClass::JOYSTICK | InputDeviceClass::EXTERNAL);
+    }
+    void prepareAxes() {
+        mFakeEventHub->addAbsoluteAxis(EVENTHUB_ID, ABS_X, RAW_X_MIN, RAW_X_MAX, 0, 0);
+        mFakeEventHub->addAbsoluteAxis(EVENTHUB_ID, ABS_Y, RAW_Y_MIN, RAW_Y_MAX, 0, 0);
+    }
+
+    void processAxis(JoystickInputMapper& mapper, int32_t axis, int32_t value) {
+        process(mapper, ARBITRARY_TIME, READ_TIME, EV_ABS, axis, value);
+    }
+
+    void processSync(JoystickInputMapper& mapper) {
+        process(mapper, ARBITRARY_TIME, READ_TIME, EV_SYN, SYN_REPORT, 0);
+    }
+
+    void prepareVirtualDisplay(int32_t orientation) {
+        setDisplayInfoAndReconfigure(VIRTUAL_DISPLAY_ID, VIRTUAL_DISPLAY_WIDTH,
+                                     VIRTUAL_DISPLAY_HEIGHT, orientation, VIRTUAL_DISPLAY_UNIQUE_ID,
+                                     NO_PORT, ViewportType::VIRTUAL);
+    }
+};
+
+const int32_t JoystickInputMapperTest::RAW_X_MIN = -32767;
+const int32_t JoystickInputMapperTest::RAW_X_MAX = 32767;
+const int32_t JoystickInputMapperTest::RAW_Y_MIN = -32767;
+const int32_t JoystickInputMapperTest::RAW_Y_MAX = 32767;
+
+TEST_F(JoystickInputMapperTest, Configure_AssignsDisplayUniqueId) {
+    prepareAxes();
+    JoystickInputMapper& mapper = addMapperAndConfigure<JoystickInputMapper>();
+
+    mFakePolicy->addInputUniqueIdAssociation(DEVICE_LOCATION, VIRTUAL_DISPLAY_UNIQUE_ID);
+
+    prepareVirtualDisplay(DISPLAY_ORIENTATION_0);
+
+    // Send an axis event
+    processAxis(mapper, ABS_X, 100);
+    processSync(mapper);
+
+    NotifyMotionArgs args;
+    ASSERT_NO_FATAL_FAILURE(mFakeListener->assertNotifyMotionWasCalled(&args));
+    ASSERT_EQ(VIRTUAL_DISPLAY_ID, args.displayId);
+
+    // Send another axis event
+    processAxis(mapper, ABS_Y, 100);
+    processSync(mapper);
+
+    ASSERT_NO_FATAL_FAILURE(mFakeListener->assertNotifyMotionWasCalled(&args));
+    ASSERT_EQ(VIRTUAL_DISPLAY_ID, args.displayId);
+}
+
 // --- PeripheralControllerTest ---
 
 class PeripheralControllerTest : public testing::Test {