diff --git a/packages/builder/src/components/common/CodeEditor/validator/tests/js.spec.ts b/packages/builder/src/components/common/CodeEditor/validator/tests/js.spec.ts
new file mode 100644
index 0000000000..be6977f35a
--- /dev/null
+++ b/packages/builder/src/components/common/CodeEditor/validator/tests/js.spec.ts
@@ -0,0 +1,71 @@
+import { validateJsTemplate } from "../js"
+import { CodeValidator } from "@/types"
+
+describe("js validator", () => {
+  it("validates valid code", () => {
+    const text = "return 7"
+    const validators = {}
+
+    const result = validateJsTemplate(text, validators)
+    expect(result).toEqual([])
+  })
+
+  it("does not validate runtime errors", () => {
+    const text = "return a"
+    const validators = {}
+
+    const result = validateJsTemplate(text, validators)
+    expect(result).toEqual([])
+  })
+
+  it("validates multiline code", () => {
+    const text = "const foo='bar'\nreturn 123"
+    const validators = {}
+
+    const result = validateJsTemplate(text, validators)
+    expect(result).toEqual([])
+  })
+
+  describe("helpers", () => {
+    const validators: CodeValidator = {
+      helperFunction: {
+        arguments: ["a", "b", "c"],
+      },
+    }
+
+    it("validates helpers with valid params", () => {
+      const text = "return helpers.helperFunction(1, 99, 'a')"
+
+      const result = validateJsTemplate(text, validators)
+      expect(result).toHaveLength(0)
+    })
+
+    it("throws on too few params", () => {
+      const text = "return helpers.helperFunction(100)"
+
+      const result = validateJsTemplate(text, validators)
+      expect(result).toEqual([
+        {
+          from: 7,
+          message: `Function "helperFunction" expects 3 parameters (a, b, c), but got 1.`,
+          severity: "error",
+          to: 34,
+        },
+      ])
+    })
+
+    it("throws on too many params", () => {
+      const text = "return helpers.helperFunction( 1, 99, 'a', 100)"
+
+      const result = validateJsTemplate(text, validators)
+      expect(result).toEqual([
+        {
+          from: 7,
+          message: `Function "helperFunction" expects 3 parameters (a, b, c), but got 4.`,
+          severity: "error",
+          to: 47,
+        },
+      ])
+    })
+  })
+})