fix issue752: generate right long keys (#879)

* fix issue752: generate right long keys

* Improve the readability of test cases

* update to raw string literal

src/emitter.cpp

@@ -556,6 +556,8 @@ void Emitter::BlockMapPrepareLongKey(EmitterNodeType::value child) {
       break;
     case EmitterNodeType::BlockSeq:
     case EmitterNodeType::BlockMap:
+      if (m_pState->HasBegunContent())
+        m_stream << "\n";
       break;
   }
 }
@@ -579,8 +581,12 @@ void Emitter::BlockMapPrepareLongKeyValue(EmitterNodeType::value child) {
     case EmitterNodeType::Scalar:
     case EmitterNodeType::FlowSeq:
     case EmitterNodeType::FlowMap:
+      SpaceOrIndentTo(true, curIndent + 1);
+      break;
     case EmitterNodeType::BlockSeq:
     case EmitterNodeType::BlockMap:
+      if (m_pState->HasBegunContent())
+        m_stream << "\n";
       SpaceOrIndentTo(true, curIndent + 1);
       break;
   }

test/integration/emitter_test.cpp

@@ -686,6 +686,52 @@ TEST_F(EmitterTest, SimpleGlobalSettings) {
   ExpectEmit("-   ? key 1\n    : value 1\n    ? key 2\n    : [a, b, c]");
 }
 
+TEST_F(EmitterTest, GlobalLongKeyOnSeq) {
+  out.SetMapFormat(LongKey);
+
+  out << BeginMap;
+  out << Key << Anchor("key");
+  out << BeginSeq << "a"
+      << "b" << EndSeq;
+  out << Value << Anchor("value");
+  out << BeginSeq << "c"
+      << "d" << EndSeq;
+  out << Key << Alias("key") << Value << Alias("value");
+  out << EndMap;
+
+  ExpectEmit(R"(? &key
+  - a
+  - b
+: &value
+  - c
+  - d
+? *key
+: *value)");
+}
+
+TEST_F(EmitterTest, GlobalLongKeyOnMap) {
+  out.SetMapFormat(LongKey);
+
+  out << BeginMap;
+  out << Key << Anchor("key");
+  out << BeginMap << "a"
+      << "b" << EndMap;
+  out << Value << Anchor("value");
+  out << BeginMap << "c"
+      << "d" << EndMap;
+  out << Key << Alias("key") << Value << Alias("value");
+  out << EndMap;
+
+  ExpectEmit(R"(? &key
+  ? a
+  : b
+: &value
+  ? c
+  : d
+? *key
+: *value)");
+}
+
 TEST_F(EmitterTest, ComplexGlobalSettings) {
   out << BeginSeq;
   out << Block;