diff --git a/rust/nix-expr/src/eval_state.rs b/rust/nix-expr/src/eval_state.rs
index c9d4728..647b466 100644
--- a/rust/nix-expr/src/eval_state.rs
+++ b/rust/nix-expr/src/eval_state.rs
@@ -877,6 +877,8 @@ mod tests {
             let v = es.new_value_apply(&f, &a).unwrap();
             assert!(es.value_is_thunk(&v));
             es.force(&v).unwrap();
+            let t = es.value_type(&v).unwrap();
+            assert!(t == ValueType::Int);
             let i = es.require_int(&v).unwrap();
             assert!(i == 3);
         })