diff --git a/src/index.spec.ts b/src/index.spec.ts
new file mode 100644
index 0000000..ffde8a8
--- /dev/null
+++ b/src/index.spec.ts
@@ -0,0 +1,5 @@
+import hello from ".";
+
+test("hello world!", () => {
+  expect(hello("world")).toBe("hello world!");
+});
diff --git a/src/index.ts b/src/index.ts
new file mode 100644
index 0000000..160fd44
--- /dev/null
+++ b/src/index.ts
@@ -0,0 +1,3 @@
+export default function hello(name: string): string {
+  return `hello ${name}!`;
+}