diff --git a/2021/1.test.ts b/2021/1.test.ts
new file mode 100644
index 0000000..ad6f0b2
--- /dev/null
+++ b/2021/1.test.ts
@@ -0,0 +1,24 @@
+import { assertEquals } from "https://deno.land/std@0.116.0/testing/asserts.ts";
+import { asyncIterator } from "./common.ts";
+import { part1, part2 } from "./1.ts";
+
+const testInput = [
+  199,
+  200,
+  208,
+  210,
+  200,
+  207,
+  240,
+  269,
+  260,
+  263,
+];
+
+Deno.test("day 1 part 1", async () => {
+  assertEquals(await part1(asyncIterator(testInput)), 7);
+});
+
+Deno.test("day 1 part 2", async () => {
+  assertEquals(await part2(asyncIterator(testInput)), 5);
+});
diff --git a/2021/common.ts b/2021/common.ts
index f7bae03..274f5f7 100644
--- a/2021/common.ts
+++ b/2021/common.ts
@@ -76,3 +76,11 @@ export async function inputNumbers(
 ): Promise<AsyncIterableIterator<number>> {
   return readStringsAsNumbers(await inputLines(day));
 }
+
+export async function* asyncIterator<T>(
+  array: T[],
+): AsyncIterableIterator<T> {
+  for (const v of array) {
+    yield v;
+  }
+}