diff --git a/tvix/eval/src/tests/tvix_tests/eval-okay-builtins-toString.exp b/tvix/eval/src/tests/tvix_tests/eval-okay-builtins-toString.exp
new file mode 100644
index 000000000..0dda9a682
--- /dev/null
+++ b/tvix/eval/src/tests/tvix_tests/eval-okay-builtins-toString.exp
@@ -0,0 +1 @@
+[ "1" ]
diff --git a/tvix/eval/src/tests/tvix_tests/eval-okay-builtins-toString.nix b/tvix/eval/src/tests/tvix_tests/eval-okay-builtins-toString.nix
new file mode 100644
index 000000000..05b2917a0
--- /dev/null
+++ b/tvix/eval/src/tests/tvix_tests/eval-okay-builtins-toString.nix
@@ -0,0 +1,6 @@
+# TODO: add some examples for the "weird" types
+[
+  (toString 1)
+  # TODO: floats must be padded to 6 digits
+  # (toString 4.2)
+]