Clean up libcutils/libutils tests.

Move tests in the same directory as the corresponding code, so it's
easier to see what is/isn't tested.

Fix naming of libcutils_tests (plural) to match the singular that's more
common (even though the plural makes more sense to me).

Add these two to system/core/'s TEST_MAPPING.

Remove obsolete AndroidTest.xml.

Fix a flaky (timing-dependent) libcutils test.

Test: ran tests
Change-Id: I7e0a31ff45c8a152562bf66fc97161594249366e
diff --git a/libutils/Looper_test.cpp b/libutils/Looper_test.cpp
new file mode 100644
index 0000000..6fdc0edc
--- /dev/null
+++ b/libutils/Looper_test.cpp
@@ -0,0 +1,746 @@
+//
+// Copyright 2010 The Android Open Source Project
+//
+
+#include <utils/Looper.h>
+#include <utils/Timers.h>
+#include <utils/StopWatch.h>
+#include <gtest/gtest.h>
+#include <unistd.h>
+#include <time.h>
+
+#include <utils/threads.h>
+
+// # of milliseconds to fudge stopwatch measurements
+#define TIMING_TOLERANCE_MS 25
+
+namespace android {
+
+enum {
+    MSG_TEST1 = 1,
+    MSG_TEST2 = 2,
+    MSG_TEST3 = 3,
+    MSG_TEST4 = 4,
+};
+
+class Pipe {
+public:
+    int sendFd;
+    int receiveFd;
+
+    Pipe() {
+        int fds[2];
+        ::pipe(fds);
+
+        receiveFd = fds[0];
+        sendFd = fds[1];
+    }
+
+    ~Pipe() {
+        if (sendFd != -1) {
+            ::close(sendFd);
+        }
+
+        if (receiveFd != -1) {
+            ::close(receiveFd);
+        }
+    }
+
+    status_t writeSignal() {
+        ssize_t nWritten = ::write(sendFd, "*", 1);
+        return nWritten == 1 ? 0 : -errno;
+    }
+
+    status_t readSignal() {
+        char buf[1];
+        ssize_t nRead = ::read(receiveFd, buf, 1);
+        return nRead == 1 ? 0 : nRead == 0 ? -EPIPE : -errno;
+    }
+};
+
+class DelayedTask : public Thread {
+    int mDelayMillis;
+
+public:
+    explicit DelayedTask(int delayMillis) : mDelayMillis(delayMillis) { }
+
+protected:
+    virtual ~DelayedTask() { }
+
+    virtual void doTask() = 0;
+
+    virtual bool threadLoop() {
+        usleep(mDelayMillis * 1000);
+        doTask();
+        return false;
+    }
+};
+
+class DelayedWake : public DelayedTask {
+    sp<Looper> mLooper;
+
+public:
+    DelayedWake(int delayMillis, const sp<Looper> looper) :
+        DelayedTask(delayMillis), mLooper(looper) {
+    }
+
+protected:
+    virtual void doTask() {
+        mLooper->wake();
+    }
+};
+
+class DelayedWriteSignal : public DelayedTask {
+    Pipe* mPipe;
+
+public:
+    DelayedWriteSignal(int delayMillis, Pipe* pipe) :
+        DelayedTask(delayMillis), mPipe(pipe) {
+    }
+
+protected:
+    virtual void doTask() {
+        mPipe->writeSignal();
+    }
+};
+
+class CallbackHandler {
+public:
+    void setCallback(const sp<Looper>& looper, int fd, int events) {
+        looper->addFd(fd, 0, events, staticHandler, this);
+    }
+
+protected:
+    virtual ~CallbackHandler() { }
+
+    virtual int handler(int fd, int events) = 0;
+
+private:
+    static int staticHandler(int fd, int events, void* data) {
+        return static_cast<CallbackHandler*>(data)->handler(fd, events);
+    }
+};
+
+class StubCallbackHandler : public CallbackHandler {
+public:
+    int nextResult;
+    int callbackCount;
+
+    int fd;
+    int events;
+
+    explicit StubCallbackHandler(int nextResult) : nextResult(nextResult),
+            callbackCount(0), fd(-1), events(-1) {
+    }
+
+protected:
+    virtual int handler(int fd, int events) {
+        callbackCount += 1;
+        this->fd = fd;
+        this->events = events;
+        return nextResult;
+    }
+};
+
+class StubMessageHandler : public MessageHandler {
+public:
+    Vector<Message> messages;
+
+    virtual void handleMessage(const Message& message) {
+        messages.push(message);
+    }
+};
+
+class LooperTest : public testing::Test {
+protected:
+    sp<Looper> mLooper;
+
+    virtual void SetUp() {
+        mLooper = new Looper(true);
+    }
+
+    virtual void TearDown() {
+        mLooper.clear();
+    }
+};
+
+
+TEST_F(LooperTest, PollOnce_WhenNonZeroTimeoutAndNotAwoken_WaitsForTimeout) {
+    StopWatch stopWatch("pollOnce");
+    int result = mLooper->pollOnce(100);
+    int32_t elapsedMillis = ns2ms(stopWatch.elapsedTime());
+
+    EXPECT_NEAR(100, elapsedMillis, TIMING_TOLERANCE_MS)
+            << "elapsed time should approx. equal timeout";
+    EXPECT_EQ(Looper::POLL_TIMEOUT, result)
+            << "pollOnce result should be LOOPER_POLL_TIMEOUT";
+}
+
+TEST_F(LooperTest, PollOnce_WhenNonZeroTimeoutAndAwokenBeforeWaiting_ImmediatelyReturns) {
+    mLooper->wake();
+
+    StopWatch stopWatch("pollOnce");
+    int result = mLooper->pollOnce(1000);
+    int32_t elapsedMillis = ns2ms(stopWatch.elapsedTime());
+
+    EXPECT_NEAR(0, elapsedMillis, TIMING_TOLERANCE_MS)
+            << "elapsed time should approx. zero because wake() was called before waiting";
+    EXPECT_EQ(Looper::POLL_WAKE, result)
+            << "pollOnce result should be Looper::POLL_CALLBACK because loop was awoken";
+}
+
+TEST_F(LooperTest, PollOnce_WhenNonZeroTimeoutAndAwokenWhileWaiting_PromptlyReturns) {
+    sp<DelayedWake> delayedWake = new DelayedWake(100, mLooper);
+    delayedWake->run("LooperTest");
+
+    StopWatch stopWatch("pollOnce");
+    int result = mLooper->pollOnce(1000);
+    int32_t elapsedMillis = ns2ms(stopWatch.elapsedTime());
+
+    EXPECT_NEAR(100, elapsedMillis, TIMING_TOLERANCE_MS)
+            << "elapsed time should approx. equal wake delay";
+    EXPECT_EQ(Looper::POLL_WAKE, result)
+            << "pollOnce result should be Looper::POLL_CALLBACK because loop was awoken";
+}
+
+TEST_F(LooperTest, PollOnce_WhenZeroTimeoutAndNoRegisteredFDs_ImmediatelyReturns) {
+    StopWatch stopWatch("pollOnce");
+    int result = mLooper->pollOnce(0);
+    int32_t elapsedMillis = ns2ms(stopWatch.elapsedTime());
+
+    EXPECT_NEAR(0, elapsedMillis, TIMING_TOLERANCE_MS)
+            << "elapsed time should be approx. zero";
+    EXPECT_EQ(Looper::POLL_TIMEOUT, result)
+            << "pollOnce result should be Looper::POLL_TIMEOUT";
+}
+
+TEST_F(LooperTest, PollOnce_WhenZeroTimeoutAndNoSignalledFDs_ImmediatelyReturns) {
+    Pipe pipe;
+    StubCallbackHandler handler(true);
+
+    handler.setCallback(mLooper, pipe.receiveFd, Looper::EVENT_INPUT);
+
+    StopWatch stopWatch("pollOnce");
+    int result = mLooper->pollOnce(0);
+    int32_t elapsedMillis = ns2ms(stopWatch.elapsedTime());
+
+    EXPECT_NEAR(0, elapsedMillis, TIMING_TOLERANCE_MS)
+            << "elapsed time should be approx. zero";
+    EXPECT_EQ(Looper::POLL_TIMEOUT, result)
+            << "pollOnce result should be Looper::POLL_TIMEOUT";
+    EXPECT_EQ(0, handler.callbackCount)
+            << "callback should not have been invoked because FD was not signalled";
+}
+
+TEST_F(LooperTest, PollOnce_WhenZeroTimeoutAndSignalledFD_ImmediatelyInvokesCallbackAndReturns) {
+    Pipe pipe;
+    StubCallbackHandler handler(true);
+
+    ASSERT_EQ(OK, pipe.writeSignal());
+    handler.setCallback(mLooper, pipe.receiveFd, Looper::EVENT_INPUT);
+
+    StopWatch stopWatch("pollOnce");
+    int result = mLooper->pollOnce(0);
+    int32_t elapsedMillis = ns2ms(stopWatch.elapsedTime());
+
+    EXPECT_NEAR(0, elapsedMillis, TIMING_TOLERANCE_MS)
+            << "elapsed time should be approx. zero";
+    EXPECT_EQ(Looper::POLL_CALLBACK, result)
+            << "pollOnce result should be Looper::POLL_CALLBACK because FD was signalled";
+    EXPECT_EQ(1, handler.callbackCount)
+            << "callback should be invoked exactly once";
+    EXPECT_EQ(pipe.receiveFd, handler.fd)
+            << "callback should have received pipe fd as parameter";
+    EXPECT_EQ(Looper::EVENT_INPUT, handler.events)
+            << "callback should have received Looper::EVENT_INPUT as events";
+}
+
+TEST_F(LooperTest, PollOnce_WhenNonZeroTimeoutAndNoSignalledFDs_WaitsForTimeoutAndReturns) {
+    Pipe pipe;
+    StubCallbackHandler handler(true);
+
+    handler.setCallback(mLooper, pipe.receiveFd, Looper::EVENT_INPUT);
+
+    StopWatch stopWatch("pollOnce");
+    int result = mLooper->pollOnce(100);
+    int32_t elapsedMillis = ns2ms(stopWatch.elapsedTime());
+
+    EXPECT_NEAR(100, elapsedMillis, TIMING_TOLERANCE_MS)
+            << "elapsed time should approx. equal timeout";
+    EXPECT_EQ(Looper::POLL_TIMEOUT, result)
+            << "pollOnce result should be Looper::POLL_TIMEOUT";
+    EXPECT_EQ(0, handler.callbackCount)
+            << "callback should not have been invoked because FD was not signalled";
+}
+
+TEST_F(LooperTest, PollOnce_WhenNonZeroTimeoutAndSignalledFDBeforeWaiting_ImmediatelyInvokesCallbackAndReturns) {
+    Pipe pipe;
+    StubCallbackHandler handler(true);
+
+    pipe.writeSignal();
+    handler.setCallback(mLooper, pipe.receiveFd, Looper::EVENT_INPUT);
+
+    StopWatch stopWatch("pollOnce");
+    int result = mLooper->pollOnce(100);
+    int32_t elapsedMillis = ns2ms(stopWatch.elapsedTime());
+
+    ASSERT_EQ(OK, pipe.readSignal())
+            << "signal should actually have been written";
+    EXPECT_NEAR(0, elapsedMillis, TIMING_TOLERANCE_MS)
+            << "elapsed time should be approx. zero";
+    EXPECT_EQ(Looper::POLL_CALLBACK, result)
+            << "pollOnce result should be Looper::POLL_CALLBACK because FD was signalled";
+    EXPECT_EQ(1, handler.callbackCount)
+            << "callback should be invoked exactly once";
+    EXPECT_EQ(pipe.receiveFd, handler.fd)
+            << "callback should have received pipe fd as parameter";
+    EXPECT_EQ(Looper::EVENT_INPUT, handler.events)
+            << "callback should have received Looper::EVENT_INPUT as events";
+}
+
+TEST_F(LooperTest, PollOnce_WhenNonZeroTimeoutAndSignalledFDWhileWaiting_PromptlyInvokesCallbackAndReturns) {
+    Pipe pipe;
+    StubCallbackHandler handler(true);
+    sp<DelayedWriteSignal> delayedWriteSignal = new DelayedWriteSignal(100, & pipe);
+
+    handler.setCallback(mLooper, pipe.receiveFd, Looper::EVENT_INPUT);
+    delayedWriteSignal->run("LooperTest");
+
+    StopWatch stopWatch("pollOnce");
+    int result = mLooper->pollOnce(1000);
+    int32_t elapsedMillis = ns2ms(stopWatch.elapsedTime());
+
+    ASSERT_EQ(OK, pipe.readSignal())
+            << "signal should actually have been written";
+    EXPECT_NEAR(100, elapsedMillis, TIMING_TOLERANCE_MS)
+            << "elapsed time should approx. equal signal delay";
+    EXPECT_EQ(Looper::POLL_CALLBACK, result)
+            << "pollOnce result should be Looper::POLL_CALLBACK because FD was signalled";
+    EXPECT_EQ(1, handler.callbackCount)
+            << "callback should be invoked exactly once";
+    EXPECT_EQ(pipe.receiveFd, handler.fd)
+            << "callback should have received pipe fd as parameter";
+    EXPECT_EQ(Looper::EVENT_INPUT, handler.events)
+            << "callback should have received Looper::EVENT_INPUT as events";
+}
+
+TEST_F(LooperTest, PollOnce_WhenCallbackAddedThenRemoved_CallbackShouldNotBeInvoked) {
+    Pipe pipe;
+    StubCallbackHandler handler(true);
+
+    handler.setCallback(mLooper, pipe.receiveFd, Looper::EVENT_INPUT);
+    pipe.writeSignal(); // would cause FD to be considered signalled
+    mLooper->removeFd(pipe.receiveFd);
+
+    StopWatch stopWatch("pollOnce");
+    int result = mLooper->pollOnce(100);
+    int32_t elapsedMillis = ns2ms(stopWatch.elapsedTime());
+
+    ASSERT_EQ(OK, pipe.readSignal())
+            << "signal should actually have been written";
+    EXPECT_NEAR(100, elapsedMillis, TIMING_TOLERANCE_MS)
+            << "elapsed time should approx. equal timeout because FD was no longer registered";
+    EXPECT_EQ(Looper::POLL_TIMEOUT, result)
+            << "pollOnce result should be Looper::POLL_TIMEOUT";
+    EXPECT_EQ(0, handler.callbackCount)
+            << "callback should not be invoked";
+}
+
+TEST_F(LooperTest, PollOnce_WhenCallbackReturnsFalse_CallbackShouldNotBeInvokedAgainLater) {
+    Pipe pipe;
+    StubCallbackHandler handler(false);
+
+    handler.setCallback(mLooper, pipe.receiveFd, Looper::EVENT_INPUT);
+
+    // First loop: Callback is registered and FD is signalled.
+    pipe.writeSignal();
+
+    StopWatch stopWatch("pollOnce");
+    int result = mLooper->pollOnce(0);
+    int32_t elapsedMillis = ns2ms(stopWatch.elapsedTime());
+
+    ASSERT_EQ(OK, pipe.readSignal())
+            << "signal should actually have been written";
+    EXPECT_NEAR(0, elapsedMillis, TIMING_TOLERANCE_MS)
+            << "elapsed time should approx. equal zero because FD was already signalled";
+    EXPECT_EQ(Looper::POLL_CALLBACK, result)
+            << "pollOnce result should be Looper::POLL_CALLBACK because FD was signalled";
+    EXPECT_EQ(1, handler.callbackCount)
+            << "callback should be invoked";
+
+    // Second loop: Callback is no longer registered and FD is signalled.
+    pipe.writeSignal();
+
+    stopWatch.reset();
+    result = mLooper->pollOnce(0);
+    elapsedMillis = ns2ms(stopWatch.elapsedTime());
+
+    ASSERT_EQ(OK, pipe.readSignal())
+            << "signal should actually have been written";
+    EXPECT_NEAR(0, elapsedMillis, TIMING_TOLERANCE_MS)
+            << "elapsed time should approx. equal zero because timeout was zero";
+    EXPECT_EQ(Looper::POLL_TIMEOUT, result)
+            << "pollOnce result should be Looper::POLL_TIMEOUT";
+    EXPECT_EQ(1, handler.callbackCount)
+            << "callback should not be invoked this time";
+}
+
+TEST_F(LooperTest, PollOnce_WhenNonCallbackFdIsSignalled_ReturnsIdent) {
+    const int expectedIdent = 5;
+    void* expectedData = this;
+
+    Pipe pipe;
+
+    pipe.writeSignal();
+    mLooper->addFd(pipe.receiveFd, expectedIdent, Looper::EVENT_INPUT, nullptr, expectedData);
+
+    StopWatch stopWatch("pollOnce");
+    int fd;
+    int events;
+    void* data;
+    int result = mLooper->pollOnce(100, &fd, &events, &data);
+    int32_t elapsedMillis = ns2ms(stopWatch.elapsedTime());
+
+    ASSERT_EQ(OK, pipe.readSignal())
+            << "signal should actually have been written";
+    EXPECT_NEAR(0, elapsedMillis, TIMING_TOLERANCE_MS)
+            << "elapsed time should be approx. zero";
+    EXPECT_EQ(expectedIdent, result)
+            << "pollOnce result should be the ident of the FD that was signalled";
+    EXPECT_EQ(pipe.receiveFd, fd)
+            << "pollOnce should have returned the received pipe fd";
+    EXPECT_EQ(Looper::EVENT_INPUT, events)
+            << "pollOnce should have returned Looper::EVENT_INPUT as events";
+    EXPECT_EQ(expectedData, data)
+            << "pollOnce should have returned the data";
+}
+
+TEST_F(LooperTest, AddFd_WhenCallbackAdded_ReturnsOne) {
+    Pipe pipe;
+    int result = mLooper->addFd(pipe.receiveFd, 0, Looper::EVENT_INPUT, nullptr, nullptr);
+
+    EXPECT_EQ(1, result)
+            << "addFd should return 1 because FD was added";
+}
+
+TEST_F(LooperTest, AddFd_WhenIdentIsNegativeAndCallbackIsNull_ReturnsError) {
+    Pipe pipe;
+    int result = mLooper->addFd(pipe.receiveFd, -1, Looper::EVENT_INPUT, nullptr, nullptr);
+
+    EXPECT_EQ(-1, result)
+            << "addFd should return -1 because arguments were invalid";
+}
+
+TEST_F(LooperTest, AddFd_WhenNoCallbackAndAllowNonCallbacksIsFalse_ReturnsError) {
+    Pipe pipe;
+    sp<Looper> looper = new Looper(false /*allowNonCallbacks*/);
+    int result = looper->addFd(pipe.receiveFd, 0, 0, nullptr, nullptr);
+
+    EXPECT_EQ(-1, result)
+            << "addFd should return -1 because arguments were invalid";
+}
+
+TEST_F(LooperTest, RemoveFd_WhenCallbackNotAdded_ReturnsZero) {
+    int result = mLooper->removeFd(1);
+
+    EXPECT_EQ(0, result)
+            << "removeFd should return 0 because FD not registered";
+}
+
+TEST_F(LooperTest, RemoveFd_WhenCallbackAddedThenRemovedTwice_ReturnsOnceFirstTimeAndReturnsZeroSecondTime) {
+    Pipe pipe;
+    StubCallbackHandler handler(false);
+    handler.setCallback(mLooper, pipe.receiveFd, Looper::EVENT_INPUT);
+
+    // First time.
+    int result = mLooper->removeFd(pipe.receiveFd);
+
+    EXPECT_EQ(1, result)
+            << "removeFd should return 1 first time because FD was registered";
+
+    // Second time.
+    result = mLooper->removeFd(pipe.receiveFd);
+
+    EXPECT_EQ(0, result)
+            << "removeFd should return 0 second time because FD was no longer registered";
+}
+
+TEST_F(LooperTest, PollOnce_WhenCallbackAddedTwice_OnlySecondCallbackShouldBeInvoked) {
+    Pipe pipe;
+    StubCallbackHandler handler1(true);
+    StubCallbackHandler handler2(true);
+
+    handler1.setCallback(mLooper, pipe.receiveFd, Looper::EVENT_INPUT);
+    handler2.setCallback(mLooper, pipe.receiveFd, Looper::EVENT_INPUT); // replace it
+    pipe.writeSignal(); // would cause FD to be considered signalled
+
+    StopWatch stopWatch("pollOnce");
+    int result = mLooper->pollOnce(100);
+    int32_t elapsedMillis = ns2ms(stopWatch.elapsedTime());
+
+    ASSERT_EQ(OK, pipe.readSignal())
+            << "signal should actually have been written";
+    EXPECT_NEAR(0, elapsedMillis, TIMING_TOLERANCE_MS)
+            << "elapsed time should approx. zero because FD was already signalled";
+    EXPECT_EQ(Looper::POLL_CALLBACK, result)
+            << "pollOnce result should be Looper::POLL_CALLBACK because FD was signalled";
+    EXPECT_EQ(0, handler1.callbackCount)
+            << "original handler callback should not be invoked because it was replaced";
+    EXPECT_EQ(1, handler2.callbackCount)
+            << "replacement handler callback should be invoked";
+}
+
+TEST_F(LooperTest, SendMessage_WhenOneMessageIsEnqueue_ShouldInvokeHandlerDuringNextPoll) {
+    sp<StubMessageHandler> handler = new StubMessageHandler();
+    mLooper->sendMessage(handler, Message(MSG_TEST1));
+
+    StopWatch stopWatch("pollOnce");
+    int result = mLooper->pollOnce(100);
+    int32_t elapsedMillis = ns2ms(stopWatch.elapsedTime());
+
+    EXPECT_NEAR(0, elapsedMillis, TIMING_TOLERANCE_MS)
+            << "elapsed time should approx. zero because message was already sent";
+    EXPECT_EQ(Looper::POLL_CALLBACK, result)
+            << "pollOnce result should be Looper::POLL_CALLBACK because message was sent";
+    EXPECT_EQ(size_t(1), handler->messages.size())
+            << "handled message";
+    EXPECT_EQ(MSG_TEST1, handler->messages[0].what)
+            << "handled message";
+}
+
+TEST_F(LooperTest, SendMessage_WhenMultipleMessagesAreEnqueued_ShouldInvokeHandlersInOrderDuringNextPoll) {
+    sp<StubMessageHandler> handler1 = new StubMessageHandler();
+    sp<StubMessageHandler> handler2 = new StubMessageHandler();
+    mLooper->sendMessage(handler1, Message(MSG_TEST1));
+    mLooper->sendMessage(handler2, Message(MSG_TEST2));
+    mLooper->sendMessage(handler1, Message(MSG_TEST3));
+    mLooper->sendMessage(handler1, Message(MSG_TEST4));
+
+    StopWatch stopWatch("pollOnce");
+    int result = mLooper->pollOnce(1000);
+    int32_t elapsedMillis = ns2ms(stopWatch.elapsedTime());
+
+    EXPECT_NEAR(0, elapsedMillis, TIMING_TOLERANCE_MS)
+            << "elapsed time should approx. zero because message was already sent";
+    EXPECT_EQ(Looper::POLL_CALLBACK, result)
+            << "pollOnce result should be Looper::POLL_CALLBACK because message was sent";
+    EXPECT_EQ(size_t(3), handler1->messages.size())
+            << "handled message";
+    EXPECT_EQ(MSG_TEST1, handler1->messages[0].what)
+            << "handled message";
+    EXPECT_EQ(MSG_TEST3, handler1->messages[1].what)
+            << "handled message";
+    EXPECT_EQ(MSG_TEST4, handler1->messages[2].what)
+            << "handled message";
+    EXPECT_EQ(size_t(1), handler2->messages.size())
+            << "handled message";
+    EXPECT_EQ(MSG_TEST2, handler2->messages[0].what)
+            << "handled message";
+}
+
+TEST_F(LooperTest, SendMessageDelayed_WhenSentToTheFuture_ShouldInvokeHandlerAfterDelayTime) {
+    sp<StubMessageHandler> handler = new StubMessageHandler();
+    mLooper->sendMessageDelayed(ms2ns(100), handler, Message(MSG_TEST1));
+
+    StopWatch stopWatch("pollOnce");
+    int result = mLooper->pollOnce(1000);
+    int32_t elapsedMillis = ns2ms(stopWatch.elapsedTime());
+
+    EXPECT_NEAR(0, elapsedMillis, TIMING_TOLERANCE_MS)
+            << "first poll should end quickly because next message timeout was computed";
+    EXPECT_EQ(Looper::POLL_WAKE, result)
+            << "pollOnce result should be Looper::POLL_WAKE due to wakeup";
+    EXPECT_EQ(size_t(0), handler->messages.size())
+            << "no message handled yet";
+
+    result = mLooper->pollOnce(1000);
+    elapsedMillis = ns2ms(stopWatch.elapsedTime());
+
+    EXPECT_EQ(size_t(1), handler->messages.size())
+            << "handled message";
+    EXPECT_EQ(MSG_TEST1, handler->messages[0].what)
+            << "handled message";
+    EXPECT_NEAR(100, elapsedMillis, TIMING_TOLERANCE_MS)
+            << "second poll should end around the time of the delayed message dispatch";
+    EXPECT_EQ(Looper::POLL_CALLBACK, result)
+            << "pollOnce result should be Looper::POLL_CALLBACK because message was sent";
+
+    result = mLooper->pollOnce(100);
+    elapsedMillis = ns2ms(stopWatch.elapsedTime());
+
+    EXPECT_NEAR(100 + 100, elapsedMillis, TIMING_TOLERANCE_MS)
+            << "third poll should timeout";
+    EXPECT_EQ(Looper::POLL_TIMEOUT, result)
+            << "pollOnce result should be Looper::POLL_TIMEOUT because there were no messages left";
+}
+
+TEST_F(LooperTest, SendMessageDelayed_WhenSentToThePast_ShouldInvokeHandlerDuringNextPoll) {
+    sp<StubMessageHandler> handler = new StubMessageHandler();
+    mLooper->sendMessageDelayed(ms2ns(-1000), handler, Message(MSG_TEST1));
+
+    StopWatch stopWatch("pollOnce");
+    int result = mLooper->pollOnce(100);
+    int32_t elapsedMillis = ns2ms(stopWatch.elapsedTime());
+
+    EXPECT_NEAR(0, elapsedMillis, TIMING_TOLERANCE_MS)
+            << "elapsed time should approx. zero because message was already sent";
+    EXPECT_EQ(Looper::POLL_CALLBACK, result)
+            << "pollOnce result should be Looper::POLL_CALLBACK because message was sent";
+    EXPECT_EQ(size_t(1), handler->messages.size())
+            << "handled message";
+    EXPECT_EQ(MSG_TEST1, handler->messages[0].what)
+            << "handled message";
+}
+
+TEST_F(LooperTest, SendMessageDelayed_WhenSentToThePresent_ShouldInvokeHandlerDuringNextPoll) {
+    sp<StubMessageHandler> handler = new StubMessageHandler();
+    mLooper->sendMessageDelayed(0, handler, Message(MSG_TEST1));
+
+    StopWatch stopWatch("pollOnce");
+    int result = mLooper->pollOnce(100);
+    int32_t elapsedMillis = ns2ms(stopWatch.elapsedTime());
+
+    EXPECT_NEAR(0, elapsedMillis, TIMING_TOLERANCE_MS)
+            << "elapsed time should approx. zero because message was already sent";
+    EXPECT_EQ(Looper::POLL_CALLBACK, result)
+            << "pollOnce result should be Looper::POLL_CALLBACK because message was sent";
+    EXPECT_EQ(size_t(1), handler->messages.size())
+            << "handled message";
+    EXPECT_EQ(MSG_TEST1, handler->messages[0].what)
+            << "handled message";
+}
+
+TEST_F(LooperTest, SendMessageAtTime_WhenSentToTheFuture_ShouldInvokeHandlerAfterDelayTime) {
+    nsecs_t now = systemTime(SYSTEM_TIME_MONOTONIC);
+    sp<StubMessageHandler> handler = new StubMessageHandler();
+    mLooper->sendMessageAtTime(now + ms2ns(100), handler, Message(MSG_TEST1));
+
+    StopWatch stopWatch("pollOnce");
+    int result = mLooper->pollOnce(1000);
+    int32_t elapsedMillis = ns2ms(stopWatch.elapsedTime());
+
+    EXPECT_NEAR(0, elapsedMillis, TIMING_TOLERANCE_MS)
+            << "first poll should end quickly because next message timeout was computed";
+    EXPECT_EQ(Looper::POLL_WAKE, result)
+            << "pollOnce result should be Looper::POLL_WAKE due to wakeup";
+    EXPECT_EQ(size_t(0), handler->messages.size())
+            << "no message handled yet";
+
+    result = mLooper->pollOnce(1000);
+    elapsedMillis = ns2ms(stopWatch.elapsedTime());
+
+    EXPECT_EQ(size_t(1), handler->messages.size())
+            << "handled message";
+    EXPECT_EQ(MSG_TEST1, handler->messages[0].what)
+            << "handled message";
+    EXPECT_NEAR(100, elapsedMillis, TIMING_TOLERANCE_MS)
+            << "second poll should end around the time of the delayed message dispatch";
+    EXPECT_EQ(Looper::POLL_CALLBACK, result)
+            << "pollOnce result should be Looper::POLL_CALLBACK because message was sent";
+
+    result = mLooper->pollOnce(100);
+    elapsedMillis = ns2ms(stopWatch.elapsedTime());
+
+    EXPECT_NEAR(100 + 100, elapsedMillis, TIMING_TOLERANCE_MS)
+            << "third poll should timeout";
+    EXPECT_EQ(Looper::POLL_TIMEOUT, result)
+            << "pollOnce result should be Looper::POLL_TIMEOUT because there were no messages left";
+}
+
+TEST_F(LooperTest, SendMessageAtTime_WhenSentToThePast_ShouldInvokeHandlerDuringNextPoll) {
+    nsecs_t now = systemTime(SYSTEM_TIME_MONOTONIC);
+    sp<StubMessageHandler> handler = new StubMessageHandler();
+    mLooper->sendMessageAtTime(now - ms2ns(1000), handler, Message(MSG_TEST1));
+
+    StopWatch stopWatch("pollOnce");
+    int result = mLooper->pollOnce(100);
+    int32_t elapsedMillis = ns2ms(stopWatch.elapsedTime());
+
+    EXPECT_NEAR(0, elapsedMillis, TIMING_TOLERANCE_MS)
+            << "elapsed time should approx. zero because message was already sent";
+    EXPECT_EQ(Looper::POLL_CALLBACK, result)
+            << "pollOnce result should be Looper::POLL_CALLBACK because message was sent";
+    EXPECT_EQ(size_t(1), handler->messages.size())
+            << "handled message";
+    EXPECT_EQ(MSG_TEST1, handler->messages[0].what)
+            << "handled message";
+}
+
+TEST_F(LooperTest, SendMessageAtTime_WhenSentToThePresent_ShouldInvokeHandlerDuringNextPoll) {
+    nsecs_t now = systemTime(SYSTEM_TIME_MONOTONIC);
+    sp<StubMessageHandler> handler = new StubMessageHandler();
+    mLooper->sendMessageAtTime(now, handler, Message(MSG_TEST1));
+
+    StopWatch stopWatch("pollOnce");
+    int result = mLooper->pollOnce(100);
+    int32_t elapsedMillis = ns2ms(stopWatch.elapsedTime());
+
+    EXPECT_NEAR(0, elapsedMillis, TIMING_TOLERANCE_MS)
+            << "elapsed time should approx. zero because message was already sent";
+    EXPECT_EQ(Looper::POLL_CALLBACK, result)
+            << "pollOnce result should be Looper::POLL_CALLBACK because message was sent";
+    EXPECT_EQ(size_t(1), handler->messages.size())
+            << "handled message";
+    EXPECT_EQ(MSG_TEST1, handler->messages[0].what)
+            << "handled message";
+}
+
+TEST_F(LooperTest, RemoveMessage_WhenRemovingAllMessagesForHandler_ShouldRemoveThoseMessage) {
+    sp<StubMessageHandler> handler = new StubMessageHandler();
+    mLooper->sendMessage(handler, Message(MSG_TEST1));
+    mLooper->sendMessage(handler, Message(MSG_TEST2));
+    mLooper->sendMessage(handler, Message(MSG_TEST3));
+    mLooper->removeMessages(handler);
+
+    StopWatch stopWatch("pollOnce");
+    int result = mLooper->pollOnce(0);
+    int32_t elapsedMillis = ns2ms(stopWatch.elapsedTime());
+
+    EXPECT_NEAR(0, elapsedMillis, TIMING_TOLERANCE_MS)
+            << "elapsed time should approx. zero because message was sent so looper was awoken";
+    EXPECT_EQ(Looper::POLL_WAKE, result)
+            << "pollOnce result should be Looper::POLL_WAKE because looper was awoken";
+    EXPECT_EQ(size_t(0), handler->messages.size())
+            << "no messages to handle";
+
+    result = mLooper->pollOnce(0);
+
+    EXPECT_EQ(Looper::POLL_TIMEOUT, result)
+            << "pollOnce result should be Looper::POLL_TIMEOUT because there was nothing to do";
+    EXPECT_EQ(size_t(0), handler->messages.size())
+            << "no messages to handle";
+}
+
+TEST_F(LooperTest, RemoveMessage_WhenRemovingSomeMessagesForHandler_ShouldRemoveThoseMessage) {
+    sp<StubMessageHandler> handler = new StubMessageHandler();
+    mLooper->sendMessage(handler, Message(MSG_TEST1));
+    mLooper->sendMessage(handler, Message(MSG_TEST2));
+    mLooper->sendMessage(handler, Message(MSG_TEST3));
+    mLooper->sendMessage(handler, Message(MSG_TEST4));
+    mLooper->removeMessages(handler, MSG_TEST3);
+    mLooper->removeMessages(handler, MSG_TEST1);
+
+    StopWatch stopWatch("pollOnce");
+    int result = mLooper->pollOnce(0);
+    int32_t elapsedMillis = ns2ms(stopWatch.elapsedTime());
+
+    EXPECT_NEAR(0, elapsedMillis, TIMING_TOLERANCE_MS)
+            << "elapsed time should approx. zero because message was sent so looper was awoken";
+    EXPECT_EQ(Looper::POLL_CALLBACK, result)
+            << "pollOnce result should be Looper::POLL_CALLBACK because two messages were sent";
+    EXPECT_EQ(size_t(2), handler->messages.size())
+            << "no messages to handle";
+    EXPECT_EQ(MSG_TEST2, handler->messages[0].what)
+            << "handled message";
+    EXPECT_EQ(MSG_TEST4, handler->messages[1].what)
+            << "handled message";
+
+    result = mLooper->pollOnce(0);
+
+    EXPECT_EQ(Looper::POLL_TIMEOUT, result)
+            << "pollOnce result should be Looper::POLL_TIMEOUT because there was nothing to do";
+    EXPECT_EQ(size_t(2), handler->messages.size())
+            << "no more messages to handle";
+}
+
+} // namespace android