[CRD iOS] Viewport fling animation

remoting/client/fling_animation_unittest.cc

+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "remoting/client/fling_animation.h"
+
+#include <cmath>
+
+#include "base/bind.h"
+#include "base/memory/ptr_util.h"
+#include "base/test/simple_test_tick_clock.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace remoting {
+
+namespace {
+
+const float kFlingTimeConstant = 325.f;
+
+}  // namespace
+
+class FlingAnimationTest : public testing::Test {
+ public:
+  void SetUp() override;
+  void TearDown() override;
+
+ protected:
+  void TickAnimation(base::TimeDelta time_delta);
+
+  // Must be called after the animation ticks.
+  void AssertDeltaChanged();
+
+  FlingAnimation fling_animation_{
+      kFlingTimeConstant,
+      base::Bind(&FlingAnimationTest::OnDeltaChanged, base::Unretained(this))};
+
+  float received_dx_ = 0.f;
+  float received_dy_ = 0.f;
+
+ private:
+  void OnDeltaChanged(float dx, float dy);
+
+  bool change_received_ = false;
+
+  // Owned by |fling_animation_|.
+  base::SimpleTestTickClock* mock_clock_;
+};
+
+void FlingAnimationTest::SetUp() {
+  mock_clock_ = new base::SimpleTestTickClock();
+  fling_animation_.SetTickClockForTest(base::WrapUnique(mock_clock_));
+}
+
+void FlingAnimationTest::TearDown() {
+  ASSERT_FALSE(change_received_);
+}
+
+void FlingAnimationTest::TickAnimation(base::TimeDelta time_delta) {
+  mock_clock_->Advance(time_delta);
+  fling_animation_.Tick();
+}
+
+void FlingAnimationTest::AssertDeltaChanged() {
+  ASSERT_TRUE(change_received_);
+  change_received_ = false;
+}
+
+void FlingAnimationTest::OnDeltaChanged(float dx, float dy) {
+  received_dx_ = dx;
+  received_dy_ = dy;
+  change_received_ = true;
+}
+
+TEST_F(FlingAnimationTest, TestNoFling) {
+  EXPECT_FALSE(fling_animation_.IsAnimationInProgress());
+
+  // This should not change the delta.
+  TickAnimation(base::TimeDelta::FromMilliseconds(100));
+}
+
+TEST_F(FlingAnimationTest, TestFlingWillEventuallyStop) {
+  fling_animation_.SetVelocity(1500.f, 1200.f);
+
+  EXPECT_TRUE(fling_animation_.IsAnimationInProgress());
+
+  TickAnimation(base::TimeDelta::FromMinutes(1));
+
+  EXPECT_FALSE(fling_animation_.IsAnimationInProgress());
+}
+
+TEST_F(FlingAnimationTest, TestFlingDeltaIsDecreasing) {
+  fling_animation_.SetVelocity(1500.f, 1200.f);
+
+  float previous_dx = std::numeric_limits<float>::infinity();
+  float previous_dy = std::numeric_limits<float>::infinity();
+
+  while (true) {
+    TickAnimation(base::TimeDelta::FromMilliseconds(16));
+    if (!fling_animation_.IsAnimationInProgress()) {
+      break;
+    }
+    AssertDeltaChanged();
+    float hyp =
+        std::sqrt(received_dx_ * received_dx_ + received_dy_ * received_dy_);
+    float prev_hyp =
+        std::sqrt(previous_dx * previous_dx + previous_dy * previous_dy);
+    EXPECT_LT(hyp, prev_hyp);
+    previous_dx = received_dx_;
+    previous_dy = received_dy_;
+  }
+}
+
+TEST_F(FlingAnimationTest, TestIgnoreLowVelocity) {
+  fling_animation_.SetVelocity(5.f, 5.f);
+
+  EXPECT_FALSE(fling_animation_.IsAnimationInProgress());
+
+  // This should not change the delta.
+  TickAnimation(base::TimeDelta::FromMilliseconds(5));
+}
+
+TEST_F(FlingAnimationTest, TestAbortAnimation) {
+  fling_animation_.SetVelocity(1500.f, 1200.f);
+
+  EXPECT_TRUE(fling_animation_.IsAnimationInProgress());
+
+  TickAnimation(base::TimeDelta::FromMilliseconds(16));
+  AssertDeltaChanged();
+  EXPECT_TRUE(fling_animation_.IsAnimationInProgress());
+
+  fling_animation_.Abort();
+  EXPECT_FALSE(fling_animation_.IsAnimationInProgress());
+}
+
+TEST_F(FlingAnimationTest, TestResetVelocity) {
+  fling_animation_.SetVelocity(1000.f, -1000.f);
+  EXPECT_TRUE(fling_animation_.IsAnimationInProgress());
+  TickAnimation(base::TimeDelta::FromMilliseconds(16));
+  EXPECT_TRUE(fling_animation_.IsAnimationInProgress());
+  AssertDeltaChanged();
+  EXPECT_GT(received_dx_, 0);
+  EXPECT_LT(received_dy_, 0);
+
+  fling_animation_.SetVelocity(-1000.f, 1000.f);
+  EXPECT_TRUE(fling_animation_.IsAnimationInProgress());
+  TickAnimation(base::TimeDelta::FromMilliseconds(16));
+  EXPECT_TRUE(fling_animation_.IsAnimationInProgress());
+  AssertDeltaChanged();
+  EXPECT_LT(received_dx_, 0);
+  EXPECT_GT(received_dy_, 0);
+}
+
+}  // namespace remoting