Create TestInputChannel and TestLooper to better test InputConsumerNoResampling

Created TestInputChannel and TestLooper to control how InputMessages are
batched in InputConsumerNoResampling_test

Bug: 297226446
Flag: EXEMPT refactor
Test: TEST=libinput_tests; m $TEST && $ANDROID_HOST_OUT/nativetest64/$TEST/$TEST --gtest_filter="InputConsumerTest*"
Change-Id: I036593b311a93ec301e8b9776b461505e853119f

10 files changed, 475 insertions, 16 deletions

diff --git a/include/input/InputConsumerNoResampling.h b/include/input/InputConsumerNoResampling.h
index 65c2914b3c..358a19158e 100644
--- a/include/input/InputConsumerNoResampling.h
+++ b/include/input/InputConsumerNoResampling.h
@@ -17,6 +17,7 @@
 #pragma once
 
 #include <input/InputTransport.h>
+#include <input/LooperInterface.h>
 #include <input/Resampler.h>
 #include <utils/Looper.h>
 
@@ -66,6 +67,16 @@ public:
 class InputConsumerNoResampling final {
 public:
     /**
+     * This constructor is exclusively for test code. Any real use of InputConsumerNoResampling must
+     * use the constructor that takes an sp<Looper> parameter instead of
+     * std::shared_ptr<LooperInterface>.
+     */
+    explicit InputConsumerNoResampling(const std::shared_ptr<InputChannel>& channel,
+                                       std::shared_ptr<LooperInterface> looper,
+                                       InputConsumerCallbacks& callbacks,
+                                       std::unique_ptr<Resampler> resampler);
+
+    /**
      * @param callbacks are used to interact with InputConsumerNoResampling. They're called whenever
      * the event is ready to consume.
      * @param looper needs to be sp and not shared_ptr because it inherits from
@@ -108,7 +119,7 @@ public:
 
 private:
     std::shared_ptr<InputChannel> mChannel;
-    sp<Looper> mLooper;
+    std::shared_ptr<LooperInterface> mLooper;
     InputConsumerCallbacks& mCallbacks;
     std::unique_ptr<Resampler> mResampler;
 
diff --git a/include/input/InputTransport.h b/include/input/InputTransport.h
index 7d11f76c85..0cd87201fb 100644
--- a/include/input/InputTransport.h
+++ b/include/input/InputTransport.h
@@ -263,7 +263,7 @@ public:
      * Return DEAD_OBJECT if the channel's peer has been closed.
      * Other errors probably indicate that the channel is broken.
      */
-    status_t sendMessage(const InputMessage* msg);
+    virtual status_t sendMessage(const InputMessage* msg);
 
     /* Receive a message sent by the other endpoint.
      *
@@ -275,14 +275,14 @@ public:
      * Return DEAD_OBJECT if the channel's peer has been closed.
      * Other errors probably indicate that the channel is broken.
      */
-    android::base::Result<InputMessage> receiveMessage();
+    virtual android::base::Result<InputMessage> receiveMessage();
 
     /* Tells whether there is a message in the channel available to be received.
      *
      * This is only a performance hint and may return false negative results. Clients should not
      * rely on availability of the message based on the return value.
      */
-    bool probablyHasInput() const;
+    virtual bool probablyHasInput() const;
 
     /* Wait until there is a message in the channel.
      *
@@ -323,11 +323,12 @@ public:
      */
     sp<IBinder> getConnectionToken() const;
 
+protected:
+    InputChannel(const std::string name, android::base::unique_fd fd, sp<IBinder> token);
+
 private:
     static std::unique_ptr<InputChannel> create(const std::string& name,
                                                 android::base::unique_fd fd, sp<IBinder> token);
-
-    InputChannel(const std::string name, android::base::unique_fd fd, sp<IBinder> token);
 };
 
 /*
diff --git a/include/input/LooperInterface.h b/include/input/LooperInterface.h
new file mode 100644
index 0000000000..2d6719c965
--- /dev/null
+++ b/include/input/LooperInterface.h
@@ -0,0 +1,39 @@
+/**
+ * Copyright 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <utils/Looper.h>
+#include <utils/StrongPointer.h>
+
+namespace android {
+
+/**
+ * LooperInterface allows the use of TestLooper in InputConsumerNoResampling without reassigning to
+ * Looper. LooperInterface is needed to control how InputConsumerNoResampling consumes and batches
+ * InputMessages.
+ */
+class LooperInterface {
+public:
+    virtual ~LooperInterface() = default;
+
+    virtual int addFd(int fd, int ident, int events, const sp<LooperCallback>& callback,
+                      void* data) = 0;
+    virtual int removeFd(int fd) = 0;
+
+    virtual sp<Looper> getLooper() const = 0;
+};
+} // namespace android
diff --git a/libs/input/InputConsumerNoResampling.cpp b/libs/input/InputConsumerNoResampling.cpp
index 99ffa683dd..eb419180e7 100644
--- a/libs/input/InputConsumerNoResampling.cpp
+++ b/libs/input/InputConsumerNoResampling.cpp
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-#define LOG_TAG "InputTransport"
+#define LOG_TAG "InputConsumerNoResampling"
 #define ATRACE_TAG ATRACE_TAG_INPUT
 
 #include <chrono>
@@ -33,8 +33,6 @@
 #include <input/PrintTools.h>
 #include <input/TraceTools.h>
 
-namespace input_flags = com::android::input::flags;
-
 namespace android {
 
 namespace {
@@ -46,6 +44,27 @@ namespace {
 const bool DEBUG_TRANSPORT_CONSUMER =
         __android_log_is_loggable(ANDROID_LOG_DEBUG, LOG_TAG "Consumer", ANDROID_LOG_INFO);
 
+/**
+ * RealLooper is a wrapper of Looper. All the member functions exclusively call the internal looper.
+ * This class' behavior is the same as Looper.
+ */
+class RealLooper final : public LooperInterface {
+public:
+    RealLooper(sp<Looper> looper) : mLooper{looper} {}
+
+    int addFd(int fd, int ident, int events, const sp<LooperCallback>& callback,
+              void* data) override {
+        return mLooper->addFd(fd, ident, events, callback, data);
+    }
+
+    int removeFd(int fd) override { return mLooper->removeFd(fd); }
+
+    sp<Looper> getLooper() const override { return mLooper; }
+
+private:
+    sp<Looper> mLooper;
+};
+
 std::unique_ptr<KeyEvent> createKeyEvent(const InputMessage& msg) {
     std::unique_ptr<KeyEvent> event = std::make_unique<KeyEvent>();
     event->initialize(msg.body.key.eventId, msg.body.key.deviceId, msg.body.key.source,
@@ -173,22 +192,20 @@ InputMessage createTimelineMessage(int32_t inputEventId, nsecs_t gpuCompletedTim
 bool isPointerEvent(const MotionEvent& motionEvent) {
     return (motionEvent.getSource() & AINPUT_SOURCE_CLASS_POINTER) == AINPUT_SOURCE_CLASS_POINTER;
 }
-
 } // namespace
 
 using android::base::Result;
-using android::base::StringPrintf;
 
 // --- InputConsumerNoResampling ---
 
 InputConsumerNoResampling::InputConsumerNoResampling(const std::shared_ptr<InputChannel>& channel,
-                                                     sp<Looper> looper,
+                                                     std::shared_ptr<LooperInterface> looper,
                                                      InputConsumerCallbacks& callbacks,
                                                      std::unique_ptr<Resampler> resampler)
-      : mChannel(channel),
-        mLooper(looper),
+      : mChannel{channel},
+        mLooper{looper},
         mCallbacks(callbacks),
-        mResampler(std::move(resampler)),
+        mResampler{std::move(resampler)},
         mFdEvents(0) {
     LOG_ALWAYS_FATAL_IF(mLooper == nullptr);
     mCallback = sp<LooperEventCallback>::make(
@@ -199,6 +216,13 @@ InputConsumerNoResampling::InputConsumerNoResampling(const std::shared_ptr<Input
     setFdEvents(ALOOPER_EVENT_INPUT);
 }
 
+InputConsumerNoResampling::InputConsumerNoResampling(const std::shared_ptr<InputChannel>& channel,
+                                                     sp<Looper> looper,
+                                                     InputConsumerCallbacks& callbacks,
+                                                     std::unique_ptr<Resampler> resampler)
+      : InputConsumerNoResampling(channel, std::make_shared<RealLooper>(looper), callbacks,
+                                  std::move(resampler)) {}
+
 InputConsumerNoResampling::~InputConsumerNoResampling() {
     ensureCalledOnLooperThread(__func__);
     consumeBatchedInputEvents(std::nullopt);
@@ -513,7 +537,7 @@ bool InputConsumerNoResampling::consumeBatchedInputEvents(
 
 void InputConsumerNoResampling::ensureCalledOnLooperThread(const char* func) const {
     sp<Looper> callingThreadLooper = Looper::getForThread();
-    if (callingThreadLooper != mLooper) {
+    if (callingThreadLooper != mLooper->getLooper()) {
         LOG(FATAL) << "The function " << func << " can only be called on the looper thread";
     }
 }
diff --git a/libs/input/tests/Android.bp b/libs/input/tests/Android.bp
index 132866bd99..43bc8948dd 100644
--- a/libs/input/tests/Android.bp
+++ b/libs/input/tests/Android.bp
@@ -16,6 +16,7 @@ cc_test {
         "BlockingQueue_test.cpp",
         "IdGenerator_test.cpp",
         "InputChannel_test.cpp",
+        "InputConsumer_test.cpp",
         "InputDevice_test.cpp",
         "InputEvent_test.cpp",
         "InputPublisherAndConsumer_test.cpp",
@@ -25,6 +26,8 @@ cc_test {
         "MotionPredictorMetricsManager_test.cpp",
         "Resampler_test.cpp",
         "RingBuffer_test.cpp",
+        "TestInputChannel.cpp",
+        "TestLooper.cpp",
         "TfLiteMotionPredictor_test.cpp",
         "TouchResampling_test.cpp",
         "TouchVideoFrame_test.cpp",
diff --git a/libs/input/tests/InputConsumer_test.cpp b/libs/input/tests/InputConsumer_test.cpp
new file mode 100644
index 0000000000..c30f243398
--- /dev/null
+++ b/libs/input/tests/InputConsumer_test.cpp
@@ -0,0 +1,123 @@
+/**
+ * Copyright 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <input/InputConsumerNoResampling.h>
+
+#include <memory>
+#include <optional>
+#include <utility>
+
+#include <TestInputChannel.h>
+#include <TestLooper.h>
+#include <android-base/logging.h>
+#include <gtest/gtest.h>
+#include <input/BlockingQueue.h>
+#include <input/InputEventBuilders.h>
+#include <utils/StrongPointer.h>
+
+namespace android {
+
+class InputConsumerTest : public testing::Test, public InputConsumerCallbacks {
+protected:
+    InputConsumerTest()
+          : mClientTestChannel{std::make_shared<TestInputChannel>("TestChannel")},
+            mTestLooper{std::make_shared<TestLooper>()} {
+        Looper::setForThread(mTestLooper->getLooper());
+        mConsumer = std::make_unique<InputConsumerNoResampling>(mClientTestChannel, mTestLooper,
+                                                                *this, /*resampler=*/nullptr);
+    }
+
+    void assertOnBatchedInputEventPendingWasCalled();
+
+    std::shared_ptr<TestInputChannel> mClientTestChannel;
+    std::shared_ptr<TestLooper> mTestLooper;
+    std::unique_ptr<InputConsumerNoResampling> mConsumer;
+
+    BlockingQueue<std::unique_ptr<KeyEvent>> mKeyEvents;
+    BlockingQueue<std::unique_ptr<MotionEvent>> mMotionEvents;
+    BlockingQueue<std::unique_ptr<FocusEvent>> mFocusEvents;
+    BlockingQueue<std::unique_ptr<CaptureEvent>> mCaptureEvents;
+    BlockingQueue<std::unique_ptr<DragEvent>> mDragEvents;
+    BlockingQueue<std::unique_ptr<TouchModeEvent>> mTouchModeEvents;
+
+private:
+    size_t onBatchedInputEventPendingInvocationCount{0};
+
+    // InputConsumerCallbacks interface
+    void onKeyEvent(std::unique_ptr<KeyEvent> event, uint32_t seq) override {
+        mKeyEvents.push(std::move(event));
+        mConsumer->finishInputEvent(seq, true);
+    }
+    void onMotionEvent(std::unique_ptr<MotionEvent> event, uint32_t seq) override {
+        mMotionEvents.push(std::move(event));
+        mConsumer->finishInputEvent(seq, true);
+    }
+    void onBatchedInputEventPending(int32_t pendingBatchSource) override {
+        if (!mConsumer->probablyHasInput()) {
+            ADD_FAILURE() << "should deterministically have input because there is a batch";
+        }
+        ++onBatchedInputEventPendingInvocationCount;
+    };
+    void onFocusEvent(std::unique_ptr<FocusEvent> event, uint32_t seq) override {
+        mFocusEvents.push(std::move(event));
+        mConsumer->finishInputEvent(seq, true);
+    };
+    void onCaptureEvent(std::unique_ptr<CaptureEvent> event, uint32_t seq) override {
+        mCaptureEvents.push(std::move(event));
+        mConsumer->finishInputEvent(seq, true);
+    };
+    void onDragEvent(std::unique_ptr<DragEvent> event, uint32_t seq) override {
+        mDragEvents.push(std::move(event));
+        mConsumer->finishInputEvent(seq, true);
+    }
+    void onTouchModeEvent(std::unique_ptr<TouchModeEvent> event, uint32_t seq) override {
+        mTouchModeEvents.push(std::move(event));
+        mConsumer->finishInputEvent(seq, true);
+    };
+};
+
+void InputConsumerTest::assertOnBatchedInputEventPendingWasCalled() {
+    ASSERT_GT(onBatchedInputEventPendingInvocationCount, 0UL)
+            << "onBatchedInputEventPending has not been called.";
+    --onBatchedInputEventPendingInvocationCount;
+}
+
+TEST_F(InputConsumerTest, MessageStreamBatchedInMotionEvent) {
+    mClientTestChannel->enqueueMessage(
+            InputMessageBuilder{InputMessage::Type::MOTION, /*seq=*/0}.build());
+    mClientTestChannel->enqueueMessage(
+            InputMessageBuilder{InputMessage::Type::MOTION, /*seq=*/1}.build());
+    mClientTestChannel->enqueueMessage(
+            InputMessageBuilder{InputMessage::Type::MOTION, /*seq=*/2}.build());
+
+    mClientTestChannel->assertNoSentMessages();
+
+    mTestLooper->invokeCallback(mClientTestChannel->getFd(), ALOOPER_EVENT_INPUT);
+
+    assertOnBatchedInputEventPendingWasCalled();
+
+    mConsumer->consumeBatchedInputEvents(std::nullopt);
+
+    std::unique_ptr<MotionEvent> batchedMotionEvent = mMotionEvents.pop();
+    ASSERT_NE(batchedMotionEvent, nullptr);
+
+    mClientTestChannel->assertFinishMessage(/*seq=*/0, /*handled=*/true);
+    mClientTestChannel->assertFinishMessage(/*seq=*/1, /*handled=*/true);
+    mClientTestChannel->assertFinishMessage(/*seq=*/2, /*handled=*/true);
+
+    EXPECT_EQ(batchedMotionEvent->getHistorySize() + 1, 3UL);
+}
+} // namespace android
diff --git a/libs/input/tests/TestInputChannel.cpp b/libs/input/tests/TestInputChannel.cpp
new file mode 100644
index 0000000000..d5f00b699b
--- /dev/null
+++ b/libs/input/tests/TestInputChannel.cpp
@@ -0,0 +1,85 @@
+/**
+ * Copyright 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define LOG_TAG "TestInputChannel"
+#define ATRACE_TAG ATRACE_TAG_INPUT
+
+#include <TestInputChannel.h>
+
+#include <android-base/logging.h>
+#include <android-base/unique_fd.h>
+#include <binder/IBinder.h>
+#include <utils/StrongPointer.h>
+
+namespace android {
+
+namespace {
+constexpr int FAKE_FD{-1};
+} // namespace
+
+// --- TestInputChannel ---
+
+TestInputChannel::TestInputChannel(const std::string& name)
+      : InputChannel{name, base::unique_fd(FAKE_FD), sp<BBinder>::make()} {}
+
+void TestInputChannel::enqueueMessage(const InputMessage& message) {
+    mReceivedMessages.push(message);
+}
+
+status_t TestInputChannel::sendMessage(const InputMessage* message) {
+    LOG_IF(FATAL, message == nullptr)
+            << "TestInputChannel " << getName() << ". No message was passed to sendMessage.";
+
+    mSentMessages.push(*message);
+    return OK;
+}
+
+base::Result<InputMessage> TestInputChannel::receiveMessage() {
+    if (mReceivedMessages.empty()) {
+        return base::Error(WOULD_BLOCK);
+    }
+    InputMessage message = mReceivedMessages.front();
+    mReceivedMessages.pop();
+    return message;
+}
+
+bool TestInputChannel::probablyHasInput() const {
+    return !mReceivedMessages.empty();
+}
+
+void TestInputChannel::assertFinishMessage(uint32_t seq, bool handled) {
+    ASSERT_FALSE(mSentMessages.empty())
+            << "TestInputChannel " << getName() << ". Cannot assert. mSentMessages is empty.";
+
+    const InputMessage& finishMessage = mSentMessages.front();
+
+    EXPECT_EQ(finishMessage.header.seq, seq)
+            << "TestInputChannel " << getName()
+            << ". Sequence mismatch. Message seq: " << finishMessage.header.seq
+            << " Expected seq: " << seq;
+
+    EXPECT_EQ(finishMessage.body.finished.handled, handled)
+            << "TestInputChannel " << getName()
+            << ". Handled value mismatch. Message val: " << std::boolalpha
+            << finishMessage.body.finished.handled << "Expected val: " << handled
+            << std::noboolalpha;
+    mSentMessages.pop();
+}
+
+void TestInputChannel::assertNoSentMessages() const {
+    ASSERT_TRUE(mSentMessages.empty());
+}
+} // namespace android
\ No newline at end of file
diff --git a/libs/input/tests/TestInputChannel.h b/libs/input/tests/TestInputChannel.h
new file mode 100644
index 0000000000..43253ec0ef
--- /dev/null
+++ b/libs/input/tests/TestInputChannel.h
@@ -0,0 +1,66 @@
+/**
+ * Copyright 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <queue>
+#include <string>
+
+#include <android-base/result.h>
+#include <gtest/gtest.h>
+#include <input/InputTransport.h>
+#include <utils/Errors.h>
+
+namespace android {
+
+class TestInputChannel final : public InputChannel {
+public:
+    explicit TestInputChannel(const std::string& name);
+
+    /**
+     * Enqueues a message in mReceivedMessages.
+     */
+    void enqueueMessage(const InputMessage& message);
+
+    /**
+     * Pushes message to mSentMessages. In the default implementation, InputChannel sends messages
+     * through a file descriptor. TestInputChannel, on the contrary, stores sent messages in
+     * mSentMessages for assertion reasons.
+     */
+    status_t sendMessage(const InputMessage* message) override;
+
+    /**
+     * Returns an InputMessage from mReceivedMessages. This is done instead of retrieving data
+     * directly from fd.
+     */
+    base::Result<InputMessage> receiveMessage() override;
+
+    /**
+     * Returns if mReceivedMessages is not empty.
+     */
+    bool probablyHasInput() const override;
+
+    void assertFinishMessage(uint32_t seq, bool handled);
+
+    void assertNoSentMessages() const;
+
+private:
+    // InputMessages received by the endpoint.
+    std::queue<InputMessage> mReceivedMessages;
+    // InputMessages sent by the endpoint.
+    std::queue<InputMessage> mSentMessages;
+};
+} // namespace android
diff --git a/libs/input/tests/TestLooper.cpp b/libs/input/tests/TestLooper.cpp
new file mode 100644
index 0000000000..e0f01ed25d
--- /dev/null
+++ b/libs/input/tests/TestLooper.cpp
@@ -0,0 +1,51 @@
+/**
+ * Copyright 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <TestLooper.h>
+
+#include <android-base/logging.h>
+
+namespace android {
+
+TestLooper::TestLooper() : mLooper(sp<Looper>::make(/*allowNonCallbacks=*/false)) {}
+
+int TestLooper::addFd(int fd, int ident, int events, const sp<LooperCallback>& callback,
+                      void* data) {
+    mCallbacks[fd] = callback;
+    constexpr int SUCCESS{1};
+    return SUCCESS;
+}
+
+int TestLooper::removeFd(int fd) {
+    if (auto it = mCallbacks.find(fd); it != mCallbacks.cend()) {
+        mCallbacks.erase(fd);
+        constexpr int SUCCESS{1};
+        return SUCCESS;
+    }
+    constexpr int FAILURE{0};
+    return FAILURE;
+}
+
+void TestLooper::invokeCallback(int fd, int events) {
+    auto it = mCallbacks.find(fd);
+    LOG_IF(FATAL, it == mCallbacks.cend()) << "Fd does not exist in mCallbacks.";
+    mCallbacks[fd]->handleEvent(fd, events, /*data=*/nullptr);
+}
+
+sp<Looper> TestLooper::getLooper() const {
+    return mLooper;
+}
+} // namespace android
\ No newline at end of file
diff --git a/libs/input/tests/TestLooper.h b/libs/input/tests/TestLooper.h
new file mode 100644
index 0000000000..3242bc7699
--- /dev/null
+++ b/libs/input/tests/TestLooper.h
@@ -0,0 +1,56 @@
+/**
+ * Copyright 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <map>
+
+#include <input/LooperInterface.h>
+
+namespace android {
+/**
+ * TestLooper provides a mechanism to directly trigger Looper's callback.
+ */
+class TestLooper final : public LooperInterface {
+public:
+    TestLooper();
+
+    /**
+     * Adds a file descriptor to mCallbacks. Ident, events, and data parameters are ignored. If
+     * addFd is called with an existent file descriptor and a different callback, the previous
+     * callback is overwritten.
+     */
+    int addFd(int fd, int ident, int events, const sp<LooperCallback>& callback,
+              void* data) override;
+
+    /**
+     * Removes a file descriptor from mCallbacks. If fd is not in mCallbacks, returns FAILURE.
+     */
+    int removeFd(int fd) override;
+
+    /**
+     * Calls handleEvent of the file descriptor. Fd must be in mCallbacks. Otherwise, invokeCallback
+     * fatally logs.
+     */
+    void invokeCallback(int fd, int events);
+
+    sp<Looper> getLooper() const override;
+
+private:
+    std::map<int /*fd*/, sp<LooperCallback>> mCallbacks;
+    sp<Looper> mLooper;
+};
+} // namespace android
\ No newline at end of file