[Remoting Client] DesktopViewport Implementation

remoting/client/desktop_viewport_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/desktop_viewport.h"
+
+#include "base/bind.h"
+#include "base/location.h"
+#include "base/strings/stringprintf.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace remoting {
+
+namespace {
+
+const float EPSILON = 0.001f;
+
+}  // namespace
+
+class DesktopViewportTest : public testing::Test {

[joedow, 2017/04/28 21:29:53]

This system is a bit different than other unit tests I've seen in our codebase. 
The most common pattern is to set your environment up (callback) save the result
after you call the method being tested, call base::RunLoop().RunUntilIdle() or
similar) and then compare the results.

The mechanism below works but I had to read the code more closely since it needs
additional checks in each method (to ensure it isn't being called multiple
times).

[Yuwei, 2017/04/28 23:53:40]

I just reversed the order to use the more common capture then assert way.

+ public:
+  void SetUp() override;
+  void TearDown() override;
+
+ protected:
+  void ExpectTransformation(const tracked_objects::Location& from_here,

[joedow, 2017/04/28 21:29:53]

I'd rename this to SetExpectedTransform() or SetExpectedTransformResult() to
make it more clear what its purpose is.

[Yuwei, 2017/04/28 23:53:40]

Renamed to AssertTransformationReceived.

+                            float scale,
+                            float offset_x,
+                            float offset_y);
+
+  DesktopViewport viewport_;
+
+ private:
+  void OnTransformationChanged(const std::array<float, 9>& matrix);
+
+  bool expect_matrix_ = false;
+  std::array<float, 9> expected_matrix_;

[joedow, 2017/04/28 21:29:53]

expected_transfrom_?  The method above doesn't mention matrix so that term seems
out of place.

[Yuwei, 2017/04/28 23:53:40]

Use |received_transformation_| now

+  tracked_objects::Location expectation_location_;
+};
+
+void DesktopViewportTest::SetUp() {
+  viewport_.RegisterOnTransformationChangedCallback(
+      base::Bind(&DesktopViewportTest::OnTransformationChanged,
+                 base::Unretained(this)),
+      true);
+}
+
+void DesktopViewportTest::TearDown() {
+  ASSERT_FALSE(expect_matrix_);
+}
+
+void DesktopViewportTest::ExpectTransformation(
+    const tracked_objects::Location& from_here,
+    float scale,
+    float offset_x,
+    float offset_y) {
+  ASSERT_FALSE(expect_matrix_) << "Previous matrix has not received yet.";
+  expect_matrix_ = true;
+  SimpleMatrix expected(scale, {offset_x, offset_y});
+  expected_matrix_ = expected.ToMatrixArray();
+  expectation_location_ = from_here;
+}
+
+void DesktopViewportTest::OnTransformationChanged(
+    const std::array<float, 9>& matrix) {
+  ASSERT_TRUE(expect_matrix_);
+
+  for (int i = 0; i < 9; i++) {
+    float diff = matrix[i] - expected_matrix_[i];
+    ASSERT_TRUE(diff > -EPSILON && diff < EPSILON)
+        << "Matrix doesn't match. \n"
+        << base::StringPrintf("Expected scale: %f, offset: (%f, %f)\n",
+                              expected_matrix_[0], expected_matrix_[2],
+                              expected_matrix_[5])
+        << base::StringPrintf("Actual scale: %f, offset: (%f, %f)\n", matrix[0],
+                              matrix[2], matrix[5])
+        << "Location: " << expectation_location_.ToString();
+  }
+
+  expect_matrix_ = false;

[joedow, 2017/04/28 21:29:53]

If SimpleMatrix had an 'isEmpty()' method, you could use it to determine if you
are expecting the callback to be run.

[Yuwei, 2017/04/28 23:53:40]

Done.

+}
+
+TEST_F(DesktopViewportTest, TestViewportInitialization1) {
+  // VP < DP. Desktop shrinks to fit.
+  // +====+------+
+  // | VP | DP   |
+  // |    |      |
+  // +====+------+
+  ExpectTransformation(FROM_HERE, 0.5f, 0.f, 0.f);
+  viewport_.SetDesktopSize(8, 6);
+  viewport_.SetSurfaceSize(2, 3);
+}
+
+TEST_F(DesktopViewportTest, TestViewportInitialization2) {
+  // VP < DP. Desktop shrinks to fit.
+  // +-----------------+
+  // |       DP        |
+  // |                 |
+  // +=================+
+  // |       VP        |
+  // +=================+
+  ExpectTransformation(FROM_HERE, 0.375, 0.f, 0.f);
+  viewport_.SetDesktopSize(8, 6);
+  viewport_.SetSurfaceSize(3, 2);
+}
+
+TEST_F(DesktopViewportTest, TestViewportInitialization3) {
+  // VP < DP. Desktop shrinks to fit.
+  // +========+----+
+  // |  VP    | DP |
+  // +========+----+
+  ExpectTransformation(FROM_HERE, 0.333f, 0.f, 0.f);
+  viewport_.SetDesktopSize(9, 3);
+  viewport_.SetSurfaceSize(2, 1);
+}
+
+TEST_F(DesktopViewportTest, TestViewportInitialization4) {
+  // VP > DP. Desktop grows to fit.
+  // +====+------+
+  // | VP | DP   |
+  // |    |      |
+  // +====+------+
+  ExpectTransformation(FROM_HERE, 4.f, 0.f, 0.f);
+  viewport_.SetDesktopSize(2, 1);
+  viewport_.SetSurfaceSize(3, 4);
+}
+
+TEST_F(DesktopViewportTest, TestMoveDesktop) {
+  // +====+------+
+  // | VP | DP   |
+  // |    |      |
+  // +====+------+
+  ExpectTransformation(FROM_HERE, 0.5f, 0.f, 0.f);
+  viewport_.SetDesktopSize(8, 6);
+  viewport_.SetSurfaceSize(2, 3);
+
+  // <--- DP
+  // +------+====+
+  // | DP   | VP |
+  // |      |    |
+  // +------+====+
+  ExpectTransformation(FROM_HERE, 0.5f, -2.f, 0.f);
+  viewport_.MoveDesktop(-2.f, 0.f);
+
+  //      +====+
+  // +----| VP |
+  // | DP |    |
+  // |    +====+
+  // +--------+
+  // Bounces back.
+  ExpectTransformation(FROM_HERE, 0.5f, -2.f, 0.f);
+  viewport_.MoveDesktop(-1.f, 1.f);
+}
+
+TEST_F(DesktopViewportTest, TestMoveAndScaleDesktop) {
+  // Number in surface coordinate.
+  //
+  // +====+------+
+  // | VP | DP   |
+  // |    |      | 3
+  // +====+------+
+  //        4
+  ExpectTransformation(FROM_HERE, 0.5f, 0.f, 0.f);
+  viewport_.SetDesktopSize(8, 6);
+  viewport_.SetSurfaceSize(2, 3);
+
+  // Scale at pivot point (2, 3) by 1.5x.
+  // +------------------+
+  // |                  |
+  // |   +====+   DP    | 4.5
+  // |   | VP |         |
+  // |   |    |         |
+  // +---+====+---------+
+  //       2     6
+  ExpectTransformation(FROM_HERE, 0.75f, -1.f, -1.5f);
+  viewport_.ScaleDesktop(2.f, 3.f, 1.5f);
+
+  // Move VP to the top-right.
+  // +-------------+====+
+  // |             | VP |
+  // |     DP      |    |
+  // |             +====+ 4.5
+  // |               2  |
+  // +------------------+
+  //         6
+  ExpectTransformation(FROM_HERE, 0.75f, -4.f, 0.f);
+  viewport_.MoveDesktop(-10000.f, 10000.f);
+
+  // Scale at (2, 0) by 0.5x.
+  //      VP
+  //       +====+
+  //    +--+----+
+  // DP |  |    |
+  //    +--+----+
+  //       +====+
+  ExpectTransformation(FROM_HERE, 0.375, -1.f, 0.375f);
+  viewport_.ScaleDesktop(2.f, 0.f, 0.5f);
+
+  // Scale all the way down.
+  // +========+
+  // |   VP   |
+  // +--------+
+  // |   DP   |
+  // +--------+
+  // |        |
+  // +========+
+  ExpectTransformation(FROM_HERE, 0.25f, 0.f, 0.75f);
+  viewport_.ScaleDesktop(20.f, 0.f, 0.0001f);
+}
+
+TEST_F(DesktopViewportTest, TestSetViewportCenter) {
+  // Numbers in desktop coordinates.
+  //
+  // +====+------+
+  // | VP | DP   |
+  // |    |      | 6
+  // +====+------+
+  //        8
+  ExpectTransformation(FROM_HERE, 0.5f, 0.f, 0.f);
+  viewport_.SetDesktopSize(8, 6);
+  viewport_.SetSurfaceSize(2, 3);
+
+  //  1.6
+  // +==+--------+
+  // |VP|2.4  DP |
+  // +==+        | 6
+  // +-----------+
+  //       8
+  ExpectTransformation(FROM_HERE, 1.25f, 0.f, 0.f);
+  viewport_.ScaleDesktop(0.f, 0.f, 2.5f);
+
+  // Move VP to center of the desktop.
+  // +------------------+
+  // |      +1.6=+      |
+  // |      | VP |2.4   | 6
+  // |      +====+      |
+  // +------------------+
+  //          8
+  ExpectTransformation(FROM_HERE, 1.25f, -4.f, -2.25f);
+  viewport_.SetViewportCenter(4.f, 3.f);
+
+  // Move it out of bound and bounce it back.
+  // +------------------+
+  // |                  |
+  // |     DP           |
+  // |               +====+
+  // |               | VP |
+  // +---------------|    |
+  //                 +====+
+  ExpectTransformation(FROM_HERE, 1.25f, -8.f, -4.5f);
+  viewport_.SetViewportCenter(1000.f, 1000.f);
+}
+
+}  // namespace remoting