diff --git a/src/test/toggleled.test.ts b/src/test/toggleled.test.ts
new file mode 100644
index 0000000..eebcc31
--- /dev/null
+++ b/src/test/toggleled.test.ts
@@ -0,0 +1,12 @@
+import { describe, expect, it } from "vitest";
+import { toggleLed } from "../toggleledd";
+
+describe("toggleLed()", () => {
+  it("turns off when on", () => {
+    expect(toggleLed(true)).toBe(false);
+  });
+
+  it("turns on when off", () => {
+    expect(toggleLed(false)).toBe(true);
+  });
+});
diff --git a/src/toggleledd.ts b/src/toggleledd.ts
new file mode 100644
index 0000000..36181c1
--- /dev/null
+++ b/src/toggleledd.ts
@@ -0,0 +1,5 @@
+export function toggleLed(currentState: boolean): boolean {
+  return !currentState; // flips LED statee
+}
+
+