diff --git a/guinep/src/test/scala/formgentests.scala b/guinep/src/test/scala/formgentests.scala
index ee5af12..4e8eb84 100644
--- a/guinep/src/test/scala/formgentests.scala
+++ b/guinep/src/test/scala/formgentests.scala
@@ -265,6 +265,17 @@ class FormGenTests extends munit.FunSuite {
     )
   )
 
+  checkGeneratedFormEquals(
+    "showNullableInt",
+    showNullableInt,
+    Form(
+      Seq(
+        FormElement.Nullable("i", FormElement.NumberInput("i", Types.IntType.Int))
+      ),
+      Map.empty
+    )
+  )
+
   checkGeneratedFormEquals(
     "isInTree",
     isInTree,
diff --git a/guinep/src/test/scala/rungentests.scala b/guinep/src/test/scala/rungentests.scala
index 8d18ceb..36580d3 100644
--- a/guinep/src/test/scala/rungentests.scala
+++ b/guinep/src/test/scala/rungentests.scala
@@ -207,6 +207,20 @@ class RunGenTests extends munit.FunSuite {
     "6.0"
   )
 
+  checkGeneratedRunResultEquals(
+    "showNullableInt",
+    showNullableInt,
+    List(null),
+    "null"
+  )
+
+  checkGeneratedRunResultEquals(
+    "showNullableInt",
+    showNullableInt,
+    List(1),
+    "1"
+  )
+
   checkGeneratedRunResultEquals(
     "isInTree",
     isInTree,
diff --git a/guinep/src/test/scala/testsdata.scala b/guinep/src/test/scala/testsdata.scala
index 3f7814b..c3838cc 100644
--- a/guinep/src/test/scala/testsdata.scala
+++ b/guinep/src/test/scala/testsdata.scala
@@ -82,6 +82,9 @@ object TestsData {
   def productSeq(s: Seq[Float]): Float =
     s.product
 
+  def showNullableInt(i: Int | Null): String =
+    if i == null then "null" else i.toString
+
   enum IntTree:
     case Leaf
     case Node(left: IntTree, value: Int, right: IntTree)