diff --git a/tests/t20018/t20018.cc b/tests/t20018/t20018.cc
index 6d36524c..d2f7a7d2 100644
--- a/tests/t20018/t20018.cc
+++ b/tests/t20018/t20018.cc
@@ -6,15 +6,22 @@ namespace t20018 {
 template <int N> struct Factorial {
     static const int value = N * Factorial<N - 1>::value;
 
-    static void print() { Factorial<N - 1>::print(); }
+    static void print(int answer) { Factorial<N - 1>::print(answer); }
 };
 
 template <> struct Factorial<0> {
     static const int value = 1;
 
-    static void print() { std::cout << "Hello world\n"; }
+    static void print(int answer)
+    {
+        std::cout << "The answer is " << answer << "\n";
+    }
 };
 
-void tmain() { Factorial<5>::print(); }
+template <typename T, int N = T::value> struct Answer {
+    static void print() { T::print(N); }
+};
+
+void tmain() { Answer<Factorial<5>>::print(); }
 }
 }
\ No newline at end of file
diff --git a/tests/t20018/test_case.h b/tests/t20018/test_case.h
index 18734c5d..22e4522a 100644
--- a/tests/t20018/test_case.h
+++ b/tests/t20018/test_case.h
@@ -35,22 +35,24 @@ TEST_CASE("t20018", "[test-case][sequence]")
     REQUIRE_THAT(puml, EndsWith("@enduml\n"));
 
     // Check if all calls exist
-    REQUIRE_THAT(
-        puml, HasCall(_A("Factorial<5>"), _A("Factorial<4>"), "__print()__"));
+    REQUIRE_THAT(puml,
+        HasCall(_A("tmain()"), _A("Answer<Factorial<5>,120>"), "__print()__"));
+    REQUIRE_THAT(puml,
+        HasCall(_A("Answer<Factorial<5>,120>"), _A("Factorial<5>"),
+            "__print(int)__"));
+    REQUIRE_THAT(puml,
+        HasCall(_A("Factorial<5>"), _A("Factorial<4>"), "__print(int)__"));
     REQUIRE_THAT(puml,
         !HasCallWithResponse(
-            _A("Factorial<5>"), _A("Factorial<4>"), "__print()__"));
-    REQUIRE_THAT(
-        puml, HasCall(_A("Factorial<4>"), _A("Factorial<3>"), "__print()__"));
-    REQUIRE_THAT(
-        puml, HasCall(_A("Factorial<3>"), _A("Factorial<2>"), "__print()__"));
-    REQUIRE_THAT(
-        puml, HasCall(_A("Factorial<2>"), _A("Factorial<1>"), "__print()__"));
-    REQUIRE_THAT(
-        puml, HasCall(_A("Factorial<1>"), _A("Factorial<0>"), "__print()__"));
-
-    // REQUIRE_THAT(puml, HasCall("A", "log_result"));
-    // REQUIRE_THAT(puml, HasCallWithResponse("B", "A", "add3"));
+            _A("Factorial<5>"), _A("Factorial<4>"), "__print(int)__"));
+    REQUIRE_THAT(puml,
+        HasCall(_A("Factorial<4>"), _A("Factorial<3>"), "__print(int)__"));
+    REQUIRE_THAT(puml,
+        HasCall(_A("Factorial<3>"), _A("Factorial<2>"), "__print(int)__"));
+    REQUIRE_THAT(puml,
+        HasCall(_A("Factorial<2>"), _A("Factorial<1>"), "__print(int)__"));
+    REQUIRE_THAT(puml,
+        HasCall(_A("Factorial<1>"), _A("Factorial<0>"), "__print(int)__"));
 
     save_puml(
         "./" + config.output_directory() + "/" + diagram->name + ".puml", puml);