test: new schedule generator

Author: kyoh86

src/lib/schedule.test.ts

@@ -0,0 +1,27 @@
+import { expect, test } from "vitest";
+import dayjs from "dayjs";
+import { generate } from "./schedule.ts";
+
+const LIMIT_TO_PREVENT_INIFINITE_LOOPS = 1000;
+
+test("generates first date closed to the start", () => {
+  const today = dayjs();
+  for (const date of generate({ start: today })) {
+    expect(today <= date).toBe(true);
+    expect(
+      date < today.add(3, "d"),
+      `expect ${date.format("YYYY-MM-DD")} is less than three days later (${today.add(3, "d").format("YYYY-MM-DD")})`,
+    ).toBe(true);
+    break;
+  }
+});
+
+test("generates days only on Monday, Wednesday or Friday", () => {
+  let count = 0; // to prevent infinite loops
+  for (const date of generate({})) {
+    expect([1, 3, 5]).contain(date.day());
+    if (count++ > LIMIT_TO_PREVENT_INIFINITE_LOOPS) {
+      break;
+    }
+  }
+});