diff --git a/test/src/unit-unicode.cpp b/test/src/unit-unicode.cpp
index f2f2f83ce..93df6808f 100644
--- a/test/src/unit-unicode.cpp
+++ b/test/src/unit-unicode.cpp
@@ -34,6 +34,25 @@ using nlohmann::json;
 
 #include <fstream>
 
+std::string create_string(int byte1, int byte2 = -1, int byte3 = -1, int byte4 = -1)
+{
+    std::string result = "\"" + std::string(1, static_cast<char>(byte1));
+    if (byte2 != -1)
+    {
+        result += std::string(1, static_cast<char>(byte2));
+    }
+    if (byte3 != -1)
+    {
+        result += std::string(1, static_cast<char>(byte3));
+    }
+    if (byte4 != -1)
+    {
+        result += std::string(1, static_cast<char>(byte4));
+    }
+    result += "\"";
+    return result;
+}
+
 TEST_CASE("RFC 3629", "[hide]")
 {
     /*
@@ -56,25 +75,6 @@ TEST_CASE("RFC 3629", "[hide]")
         UTF8-tail   = %x80-BF
     */
 
-    auto create_string = [](int byte1, int byte2 = -1, int byte3 = -1, int byte4 = -1)
-    {
-        std::string result = "\"" + std::string(1, static_cast<char>(byte1));
-        if (byte2 != -1)
-        {
-            result += std::string(1, static_cast<char>(byte2));
-        }
-        if (byte3 != -1)
-        {
-            result += std::string(1, static_cast<char>(byte3));
-        }
-        if (byte4 != -1)
-        {
-            result += std::string(1, static_cast<char>(byte4));
-        }
-        result += "\"";
-        return result;
-    };
-
     SECTION("ill-formed first byte")
     {
         for (int byte1 = 0x80; byte1 <= 0xC1; ++byte1)