Add tests for custom decoding

test/node/node_test.cpp

@@ -41,6 +41,23 @@ template <class T> using CustomVector = std::vector<T,CustomAllocator<T>>;
 template <class T> using CustomList = std::list<T,CustomAllocator<T>>;
 template <class K, class V, class C=std::less<K>> using CustomMap = std::map<K,V,C,CustomAllocator<std::pair<const K,V>>>;
 
+struct Vec3 {
+  double x, y, z;
+  bool operator==(const Vec3& rhs) const {
+    return x == rhs.x && y == rhs.y && z == rhs.z;
+  }
+};
+
+#ifdef YAML_CPP_HAS_DECODE_DISPATCHER
+struct NonDefCtorVec3 {
+  double x, y, z;
+  NonDefCtorVec3(double x, double y, double z) : x(x), y(y), z(z) {}
+  bool operator==(const NonDefCtorVec3& rhs) const {
+    return x == rhs.x && y == rhs.y && z == rhs.z;
+  }
+};
+#endif
+
 }  // anonymous namespace
 
 using ::testing::AnyOf;
@@ -55,6 +72,41 @@ using ::testing::Eq;
   }
 
 namespace YAML {
+
+template<>
+struct convert<Vec3> {
+  static Node encode(const Vec3& rhs) {
+    Node node;
+    node.push_back(rhs.x);
+    node.push_back(rhs.y);
+    node.push_back(rhs.z);
+    return node;
+  }
+
+  static bool decode(const Node& node, Vec3& rhs) {
+    if(!node.IsSequence() || node.size() != 3) {
+      return false;
+    }
+
+    rhs.x = node[0].as<double>();
+    rhs.y = node[1].as<double>();
+    rhs.z = node[2].as<double>();
+    return true;
+  }
+};
+
+#ifdef YAML_CPP_HAS_DECODE_DISPATCHER
+template <>
+struct decode_dispatcher<NonDefCtorVec3> {
+  static std::optional<NonDefCtorVec3> dispatch(const Node& node) {
+    if (!node.IsSequence() || node.size() != 3) {
+      return std::nullopt;
+    }
+    return {{node[0].as<double>(), node[1].as<double>(), node[2].as<double>()}};
+  }
+};
+#endif
+
 namespace {
 TEST(NodeTest, SimpleScalar) {
   Node node = Node("Hello, World!");
@@ -645,6 +697,28 @@ TEST(NodeTest, AccessNonexistentKeyOnConstNode) {
   ASSERT_FALSE(other["5"]);
 }
 
+TEST(NodeTest, CustomClassDecoding) {
+  YAML::Node node;
+  node.push_back(1.0);
+  node.push_back(2.0);
+  node.push_back(3.0);
+  ASSERT_TRUE(node.IsSequence());
+  EXPECT_EQ(node.as<Vec3>(), (Vec3{1.0, 2.0, 3.0}));
+}
+
+TEST(NodeTest, CustomNonDefaultConstructibleClassDecoding) {
+#ifdef YAML_CPP_HAS_DECODE_DISPATCHER
+  YAML::Node node;
+  node.push_back(1.0);
+  node.push_back(2.0);
+  node.push_back(3.0);
+  ASSERT_TRUE(node.IsSequence());
+  EXPECT_EQ(node.as<NonDefCtorVec3>(), (NonDefCtorVec3{1.0, 2.0, 3.0}));
+#else
+  GTEST_SKIP() << "Compile with C++17 for customizing non-default-constructible custom types.";
+#endif
+}
+
 class NodeEmitterTest : public ::testing::Test {
  protected:
   void ExpectOutput(const std::string& output, const Node& node) {