diff --git a/testdata/diff/create_function/issue_329_immutable_udt_generated_col/diff.sql b/testdata/diff/create_function/issue_329_immutable_udt_generated_col/diff.sql
new file mode 100644
index 00000000..e69de29b
diff --git a/testdata/diff/create_function/issue_329_immutable_udt_generated_col/new.sql b/testdata/diff/create_function/issue_329_immutable_udt_generated_col/new.sql
new file mode 100644
index 00000000..72e5154b
--- /dev/null
+++ b/testdata/diff/create_function/issue_329_immutable_udt_generated_col/new.sql
@@ -0,0 +1,18 @@
+CREATE TYPE item_status AS ENUM ('pending', 'active', 'done');
+
+CREATE FUNCTION compute_status(x integer)
+RETURNS item_status
+LANGUAGE plpgsql
+IMMUTABLE
+AS $$
+BEGIN
+    IF x > 0 THEN RETURN 'active'::item_status; END IF;
+    IF x < 0 THEN RETURN 'done'::item_status; END IF;
+    RETURN 'pending'::item_status;
+END;
+$$;
+
+CREATE TABLE demo (
+    id integer PRIMARY KEY,
+    status item_status GENERATED ALWAYS AS (compute_status(id)) STORED
+);
diff --git a/testdata/diff/create_function/issue_329_immutable_udt_generated_col/old.sql b/testdata/diff/create_function/issue_329_immutable_udt_generated_col/old.sql
new file mode 100644
index 00000000..72e5154b
--- /dev/null
+++ b/testdata/diff/create_function/issue_329_immutable_udt_generated_col/old.sql
@@ -0,0 +1,18 @@
+CREATE TYPE item_status AS ENUM ('pending', 'active', 'done');
+
+CREATE FUNCTION compute_status(x integer)
+RETURNS item_status
+LANGUAGE plpgsql
+IMMUTABLE
+AS $$
+BEGIN
+    IF x > 0 THEN RETURN 'active'::item_status; END IF;
+    IF x < 0 THEN RETURN 'done'::item_status; END IF;
+    RETURN 'pending'::item_status;
+END;
+$$;
+
+CREATE TABLE demo (
+    id integer PRIMARY KEY,
+    status item_status GENERATED ALWAYS AS (compute_status(id)) STORED
+);
diff --git a/testdata/diff/create_function/issue_329_immutable_udt_generated_col/plan.json b/testdata/diff/create_function/issue_329_immutable_udt_generated_col/plan.json
new file mode 100644
index 00000000..8a6194d7
--- /dev/null
+++ b/testdata/diff/create_function/issue_329_immutable_udt_generated_col/plan.json
@@ -0,0 +1,9 @@
+{
+  "version": "1.0.0",
+  "pgschema_version": "1.7.2",
+  "created_at": "1970-01-01T00:00:00Z",
+  "source_fingerprint": {
+    "hash": "86da603163a64eef536f98f999b32298bf87e18b41f76f684fba15e74d7f493a"
+  },
+  "groups": null
+}
diff --git a/testdata/diff/create_function/issue_329_immutable_udt_generated_col/plan.sql b/testdata/diff/create_function/issue_329_immutable_udt_generated_col/plan.sql
new file mode 100644
index 00000000..e69de29b
diff --git a/testdata/diff/create_function/issue_329_immutable_udt_generated_col/plan.txt b/testdata/diff/create_function/issue_329_immutable_udt_generated_col/plan.txt
new file mode 100644
index 00000000..241994af
--- /dev/null
+++ b/testdata/diff/create_function/issue_329_immutable_udt_generated_col/plan.txt
@@ -0,0 +1 @@
+No changes detected.
diff --git a/testdata/diff/create_function/issue_329_immutable_udt_return/diff.sql b/testdata/diff/create_function/issue_329_immutable_udt_return/diff.sql
new file mode 100644
index 00000000..e69de29b
diff --git a/testdata/diff/create_function/issue_329_immutable_udt_return/new.sql b/testdata/diff/create_function/issue_329_immutable_udt_return/new.sql
new file mode 100644
index 00000000..db777570
--- /dev/null
+++ b/testdata/diff/create_function/issue_329_immutable_udt_return/new.sql
@@ -0,0 +1,13 @@
+CREATE TYPE item_status AS ENUM ('pending', 'active', 'done');
+
+CREATE FUNCTION compute_status(x integer)
+RETURNS item_status
+LANGUAGE plpgsql
+IMMUTABLE
+AS $$
+BEGIN
+    IF x > 0 THEN RETURN 'active'::item_status; END IF;
+    IF x < 0 THEN RETURN 'done'::item_status; END IF;
+    RETURN 'pending'::item_status;
+END;
+$$;
diff --git a/testdata/diff/create_function/issue_329_immutable_udt_return/old.sql b/testdata/diff/create_function/issue_329_immutable_udt_return/old.sql
new file mode 100644
index 00000000..db777570
--- /dev/null
+++ b/testdata/diff/create_function/issue_329_immutable_udt_return/old.sql
@@ -0,0 +1,13 @@
+CREATE TYPE item_status AS ENUM ('pending', 'active', 'done');
+
+CREATE FUNCTION compute_status(x integer)
+RETURNS item_status
+LANGUAGE plpgsql
+IMMUTABLE
+AS $$
+BEGIN
+    IF x > 0 THEN RETURN 'active'::item_status; END IF;
+    IF x < 0 THEN RETURN 'done'::item_status; END IF;
+    RETURN 'pending'::item_status;
+END;
+$$;
diff --git a/testdata/diff/create_function/issue_329_immutable_udt_return/plan.json b/testdata/diff/create_function/issue_329_immutable_udt_return/plan.json
new file mode 100644
index 00000000..13649be7
--- /dev/null
+++ b/testdata/diff/create_function/issue_329_immutable_udt_return/plan.json
@@ -0,0 +1,9 @@
+{
+  "version": "1.0.0",
+  "pgschema_version": "1.7.2",
+  "created_at": "1970-01-01T00:00:00Z",
+  "source_fingerprint": {
+    "hash": "1c87af96b295a39074a0294af29bcb08fb6d4fefd916381bd052f966d8f59400"
+  },
+  "groups": null
+}
diff --git a/testdata/diff/create_function/issue_329_immutable_udt_return/plan.sql b/testdata/diff/create_function/issue_329_immutable_udt_return/plan.sql
new file mode 100644
index 00000000..e69de29b
diff --git a/testdata/diff/create_function/issue_329_immutable_udt_return/plan.txt b/testdata/diff/create_function/issue_329_immutable_udt_return/plan.txt
new file mode 100644
index 00000000..241994af
--- /dev/null
+++ b/testdata/diff/create_function/issue_329_immutable_udt_return/plan.txt
@@ -0,0 +1 @@
+No changes detected.