Add simple unescaping test

src/test.cpp

@@ -208,6 +208,17 @@ TEST_CASE("parser3") {
 
 TEST_CASE("streaming") { testStreaming(json); }
 
+TEST_CASE("unescaping") {
+  auto c = noopCallbacks();
+  c.on_string_data = +[](void *, const char *buf, int len) {
+    CHECK(std::string(buf, len) == "\n");
+  };
+  std::string copy = "\"\\n\"";
+  parser3::Parser3 parser(&c, nullptr);
+  CHECK(parser.parse(copy.data(), copy.length()) == parser3::S_AGAIN);
+  CHECK(parser.parse(nullptr, 0) == parser3::S_OK);
+}
+
 TEST_CASE("bench3") {
   auto c = noopCallbacks();
   ankerl::nanobench::Bench bench;