Helium: Adding vector clock

blimp/net/helium/vector_clock_unittest.cc

Index: blimp/net/helium/vector_clock_unittest.cc
diff --git a/blimp/net/helium/vector_clock_unittest.cc b/blimp/net/helium/vector_clock_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..f67e86b5559e64079ce71bcd5cc0eed35ca05835
--- /dev/null
+++ b/blimp/net/helium/vector_clock_unittest.cc
@@ -0,0 +1,153 @@
+// Copyright 2016 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 "blimp/net/helium/vector_clock.h"
+
+#include "base/macros.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace blimp {
+namespace {
+
+class VectorClockComparisonTest
+    : public ::testing::TestWithParam<
+          std::tuple<VectorClock, VectorClock, VectorClock::Comparison>> {
+ public:
+  VectorClockComparisonTest() {}
+  ~VectorClockComparisonTest() override {}
+};
+
+TEST_P(VectorClockComparisonTest, CompareTo) {
+  auto param = GetParam();
+  VectorClock v1 = std::get<0>(param);
+  VectorClock v2 = std::get<1>(param);
+  VectorClock::Comparison expected = std::get<2>(param);
+  EXPECT_EQ(expected, v1.CompareTo(v2));
+}
+
+INSTANTIATE_TEST_CASE_P(

[Kevin M, 2016/09/27 17:31:10]

Wow, this is pretty cool. I was unaware of this style of unit test!

+    LessThan,
+    VectorClockComparisonTest,
+    ::testing::Values(std::make_tuple(VectorClock(1, 2),
+                                      VectorClock(1, 3),
+                                      VectorClock::Comparison::LessThan),
+                      std::make_tuple(VectorClock(1, 2),
+                                      VectorClock(2, 2),
+                                      VectorClock::Comparison::LessThan)));
+
+INSTANTIATE_TEST_CASE_P(
+    GreaterThan,
+    VectorClockComparisonTest,
+    ::testing::Values(std::make_tuple(VectorClock(1, 3),
+                                      VectorClock(1, 2),
+                                      VectorClock::Comparison::GreaterThan),
+                      std::make_tuple(VectorClock(2, 2),
+                                      VectorClock(1, 2),
+                                      VectorClock::Comparison::GreaterThan)));
+
+INSTANTIATE_TEST_CASE_P(
+    Conflicts,
+    VectorClockComparisonTest,
+    ::testing::Values(std::make_tuple(VectorClock(1, 2),
+                                      VectorClock(0, 1),
+                                      VectorClock::Comparison::Conflicts),
+                      std::make_tuple(VectorClock(1, 2),
+                                      VectorClock(0, 3),
+                                      VectorClock::Comparison::Conflicts),
+                      std::make_tuple(VectorClock(1, 2),
+                                      VectorClock(2, 3),
+                                      VectorClock::Comparison::Conflicts)));
+
+INSTANTIATE_TEST_CASE_P(
+    EqualTo,
+    VectorClockComparisonTest,
+    ::testing::Values(std::make_tuple(VectorClock(1, 1),
+                                      VectorClock(1, 1),
+                                      VectorClock::Comparison::EqualTo),
+                      std::make_tuple(VectorClock(2, 3),
+                                      VectorClock(2, 3),
+                                      VectorClock::Comparison::EqualTo),
+                      std::make_tuple(VectorClock(3, 2),
+                                      VectorClock(3, 2),
+                                      VectorClock::Comparison::EqualTo)));
+
+class VectorClockTest : public testing::Test {
+ public:
+  VectorClockTest() {}
+  ~VectorClockTest() override {}
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(VectorClockTest);
+};
+
+TEST_F(VectorClockTest, IncrementLocal1) {
+  VectorClock v(0, 0);
+  v.IncrementLocal();
+  EXPECT_EQ(1, v.local_revision());
+  EXPECT_EQ(0, v.remote_revision());
+}
+
+TEST_F(VectorClockTest, IncrementLocal2) {
+  VectorClock v(4, 5);
+  v.IncrementLocal();
+  EXPECT_EQ(5, v.local_revision());
+  EXPECT_EQ(5, v.remote_revision());
+}
+
+TEST_F(VectorClockTest, MergeWith1) {
+  VectorClock v1(1, 2);

[Kevin M, 2016/09/27 17:31:10]

We could cut down on the number of test cases by making a helper function that
verifies the associativity of merges.

VerifyMerge(1, 2, 1, 4) ==> merge((1, 2), (1, 4)); merge((1, 4), (1,2))

+  VectorClock v2(1, 4);
+
+  VectorClock v3 = v1.MergeWith(v2);
+  EXPECT_EQ(1, v3.local_revision());
+  EXPECT_EQ(4, v3.remote_revision());
+}
+
+TEST_F(VectorClockTest, MergeWith2) {
+  VectorClock v1(1, 4);
+  VectorClock v2(1, 2);
+
+  VectorClock v3 = v1.MergeWith(v2);
+  EXPECT_EQ(1, v3.local_revision());
+  EXPECT_EQ(4, v3.remote_revision());
+}
+
+TEST_F(VectorClockTest, MergeWith3) {
+  VectorClock v1(1, 4);
+  VectorClock v2(2, 4);
+
+  VectorClock v3 = v1.MergeWith(v2);
+  EXPECT_EQ(2, v3.local_revision());
+  EXPECT_EQ(4, v3.remote_revision());
+}
+
+TEST_F(VectorClockTest, MergeWith4) {
+  VectorClock v1(2, 4);
+  VectorClock v2(1, 4);
+
+  VectorClock v3 = v1.MergeWith(v2);
+  EXPECT_EQ(2, v3.local_revision());
+  EXPECT_EQ(4, v3.remote_revision());
+}
+
+TEST_F(VectorClockTest, MergeWith5) {
+  VectorClock v1(1, 2);
+  VectorClock v2(3, 4);
+
+  VectorClock v3 = v1.MergeWith(v2);
+  EXPECT_EQ(3, v3.local_revision());
+  EXPECT_EQ(4, v3.remote_revision());
+}
+
+TEST_F(VectorClockTest, MergeWith6) {
+  VectorClock v1(3, 4);
+  VectorClock v2(1, 2);
+
+  VectorClock v3 = v1.MergeWith(v2);
+  EXPECT_EQ(3, v3.local_revision());
+  EXPECT_EQ(4, v3.remote_revision());
+}
+
+}  // namespace
+}  // namespace blimp