SurfaceFlinger: add a unit test for DispSyncSource

Add a unit test for DispSyncSource class.

Fixes: 124799942
Test: adb shell /data/nativetest64/libsurfaceflinger_unittest/libsurfaceflinger_unittest --gtest_repeat=20
Change-Id: I76b824f25a9cbc8ba204a702e446fe9ac073be02
diff --git a/services/surfaceflinger/tests/unittests/DispSyncSourceTest.cpp b/services/surfaceflinger/tests/unittests/DispSyncSourceTest.cpp
new file mode 100644
index 0000000..92bdebd
--- /dev/null
+++ b/services/surfaceflinger/tests/unittests/DispSyncSourceTest.cpp
@@ -0,0 +1,164 @@
+/*
+ * Copyright 2019 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.
+ */
+
+#undef LOG_TAG
+#define LOG_TAG "LibSurfaceFlingerUnittests"
+#define LOG_NDEBUG 0
+
+#include <inttypes.h>
+
+#include <gmock/gmock.h>
+#include <gtest/gtest.h>
+
+#include <log/log.h>
+
+#include "AsyncCallRecorder.h"
+#include "Scheduler/DispSyncSource.h"
+#include "mock/MockDispSync.h"
+
+namespace android {
+namespace {
+
+using namespace std::chrono_literals;
+using testing::Return;
+
+class DispSyncSourceTest : public testing::Test, private VSyncSource::Callback {
+protected:
+    DispSyncSourceTest();
+    ~DispSyncSourceTest() override;
+
+    void createDispSync();
+    void createDispSyncSource();
+
+    void onVSyncEvent(nsecs_t when) override;
+
+    std::unique_ptr<mock::DispSync> mDispSync;
+    std::unique_ptr<DispSyncSource> mDispSyncSource;
+
+    AsyncCallRecorder<void (*)(nsecs_t)> mVSyncEventCallRecorder;
+
+    static constexpr std::chrono::nanoseconds mPhaseOffset = 6ms;
+    static constexpr int mIterations = 100;
+};
+
+DispSyncSourceTest::DispSyncSourceTest() {
+    const ::testing::TestInfo* const test_info =
+            ::testing::UnitTest::GetInstance()->current_test_info();
+    ALOGD("**** Setting up for %s.%s\n", test_info->test_case_name(), test_info->name());
+}
+
+DispSyncSourceTest::~DispSyncSourceTest() {
+    const ::testing::TestInfo* const test_info =
+            ::testing::UnitTest::GetInstance()->current_test_info();
+    ALOGD("**** Tearing down after %s.%s\n", test_info->test_case_name(), test_info->name());
+}
+
+void DispSyncSourceTest::onVSyncEvent(nsecs_t when) {
+    ALOGD("onVSyncEvent: %" PRId64, when);
+
+    mVSyncEventCallRecorder.recordCall(when);
+}
+
+void DispSyncSourceTest::createDispSync() {
+    mDispSync = std::make_unique<mock::DispSync>();
+}
+
+void DispSyncSourceTest::createDispSyncSource() {
+    createDispSync();
+    mDispSyncSource = std::make_unique<DispSyncSource>(mDispSync.get(), mPhaseOffset.count(), true,
+                                                       "DispSyncSourceTest");
+    mDispSyncSource->setCallback(this);
+}
+
+/* ------------------------------------------------------------------------
+ * Test cases
+ */
+
+TEST_F(DispSyncSourceTest, createDispSync) {
+    createDispSync();
+    EXPECT_TRUE(mDispSync);
+}
+
+TEST_F(DispSyncSourceTest, createDispSyncSource) {
+    createDispSyncSource();
+    EXPECT_TRUE(mDispSyncSource);
+}
+
+TEST_F(DispSyncSourceTest, noCallbackAfterInit) {
+    createDispSyncSource();
+    EXPECT_TRUE(mDispSyncSource);
+
+    // DispSyncSource starts with Vsync disabled
+    mDispSync->triggerCallback();
+    EXPECT_FALSE(mVSyncEventCallRecorder.waitForUnexpectedCall().has_value());
+}
+
+TEST_F(DispSyncSourceTest, waitForCallbacks) {
+    createDispSyncSource();
+    EXPECT_TRUE(mDispSyncSource);
+
+    mDispSyncSource->setVSyncEnabled(true);
+    EXPECT_EQ(mDispSync->getCallbackPhase(), mPhaseOffset.count());
+
+    for (int i = 0; i < mIterations; i++) {
+        mDispSync->triggerCallback();
+        EXPECT_TRUE(mVSyncEventCallRecorder.waitForCall().has_value());
+    }
+}
+
+TEST_F(DispSyncSourceTest, waitForCallbacksWithPhaseChange) {
+    createDispSyncSource();
+    EXPECT_TRUE(mDispSyncSource);
+
+    mDispSyncSource->setVSyncEnabled(true);
+    EXPECT_EQ(mDispSync->getCallbackPhase(), mPhaseOffset.count());
+
+    for (int i = 0; i < mIterations; i++) {
+        mDispSync->triggerCallback();
+        EXPECT_TRUE(mVSyncEventCallRecorder.waitForCall().has_value());
+    }
+
+    EXPECT_CALL(*mDispSync, getPeriod()).Times(1).WillOnce(Return(16666666));
+    mDispSyncSource->setPhaseOffset((mPhaseOffset / 2).count());
+
+    EXPECT_EQ(mDispSync->getCallbackPhase(), (mPhaseOffset / 2).count());
+
+    for (int i = 0; i < mIterations; i++) {
+        mDispSync->triggerCallback();
+        EXPECT_TRUE(mVSyncEventCallRecorder.waitForCall().has_value());
+    }
+}
+
+TEST_F(DispSyncSourceTest, pauseCallbacks) {
+    createDispSyncSource();
+    EXPECT_TRUE(mDispSyncSource);
+
+    mDispSyncSource->setVSyncEnabled(true);
+    EXPECT_EQ(mDispSync->getCallbackPhase(), mPhaseOffset.count());
+    mDispSync->triggerCallback();
+    EXPECT_TRUE(mVSyncEventCallRecorder.waitForCall().has_value());
+
+    mDispSyncSource->pauseVsyncCallback(true);
+    mDispSync->triggerCallback();
+    EXPECT_FALSE(mVSyncEventCallRecorder.waitForUnexpectedCall().has_value());
+
+    mDispSyncSource->pauseVsyncCallback(false);
+    mDispSync->triggerCallback();
+    EXPECT_TRUE(mVSyncEventCallRecorder.waitForUnexpectedCall().has_value());
+}
+
+} // namespace
+} // namespace android