message: add Collection tests
diff: @@ -456,6 +456,21 @@ TEST(CollectionTest, IterateArrayValues) {
  ASSERT_EQ(8U, state);
  }
  +TEST(CollectionTest, AppendArray) {
  + std::string const value("[1,2,null,true,\"foo\"]");
  +
  + Parser parser;
  + parser.parse(value);
  + Slice s(parser.start());
  +
  + Builder b;
  + b.openArray();
  + Collection::appendArray(b, s);
  + b.close();
  +
  + ASSERT_EQ(b.toJson(), value);
  +}
  +
  TEST(CollectionTest, FilterNonArray) {
  std::string const value("null");
  Parser parser;
  