import { describe, expect, it } from "vitest";
import {
formatISODate,
formatYNABMonth,
getCurrentMonth,
getHistoricalMonths,
getToday,
isValidISODate,
isValidYNABMonth,
subtractMonths,
yearMonthToYNABMonth,
} from "../dateUtils.js";
describe("dateUtils", () => {
describe("formatYNABMonth", () => {
it("should format date as YYYY-MM-01", () => {
const date = new Date("2024-03-15T10:30:00.000Z");
expect(formatYNABMonth(date)).toBe("2024-03-01");
});
it("should handle December correctly", () => {
const date = new Date("2024-12-31T23:59:59.999Z");
expect(formatYNABMonth(date)).toBe("2024-12-01");
});
});
describe("formatISODate", () => {
it("should format date as YYYY-MM-DD", () => {
const date = new Date("2024-03-15T10:30:00.000Z");
expect(formatISODate(date)).toBe("2024-03-15");
});
});
describe("getCurrentMonth", () => {
it("should return current month in YYYY-MM-01 format", () => {
const result = getCurrentMonth();
expect(result).toMatch(/^\d{4}-\d{2}-01$/);
});
});
describe("getToday", () => {
it("should return today in YYYY-MM-DD format", () => {
const result = getToday();
expect(result).toMatch(/^\d{4}-\d{2}-\d{2}$/);
});
});
describe("getHistoricalMonths", () => {
it("should generate correct number of historical months", () => {
const baseDate = new Date("2024-03-15");
const months = getHistoricalMonths(3, baseDate);
expect(months).toHaveLength(3);
expect(months[0]).toBe("2024-03-01"); // Current month (i=0)
expect(months[1]).toBe("2024-02-01"); // 1 month back
expect(months[2]).toBe("2024-01-01"); // 2 months back
});
it("should handle year boundary correctly", () => {
const baseDate = new Date("2024-01-15");
const months = getHistoricalMonths(3, baseDate);
expect(months).toHaveLength(3);
expect(months[0]).toBe("2024-01-01");
expect(months[1]).toBe("2023-12-01");
expect(months[2]).toBe("2023-11-01");
});
it("should use current date when no base date provided", () => {
const months = getHistoricalMonths(2);
expect(months).toHaveLength(2);
expect(months[0]).toMatch(/^\d{4}-\d{2}-01$/);
expect(months[1]).toMatch(/^\d{4}-\d{2}-01$/);
});
it("should generate 6 months correctly (bug test case)", () => {
const baseDate = new Date("2025-08-15");
const months = getHistoricalMonths(6, baseDate);
expect(months).toEqual([
"2025-08-01",
"2025-07-01",
"2025-06-01",
"2025-05-01",
"2025-04-01",
"2025-03-01",
]);
// Ensure no duplicates (the original bug)
const uniqueMonths = new Set(months);
expect(uniqueMonths.size).toBe(6);
});
});
describe("subtractMonths", () => {
it("should subtract months correctly", () => {
const baseDate = new Date("2024-03-15");
const result = subtractMonths(baseDate, 2);
expect(result.getFullYear()).toBe(2024);
expect(result.getMonth()).toBe(0); // January (0-indexed)
// Note: When subtracting months, if the target month doesn't have enough days,
// JavaScript adjusts the date (e.g., March 15 - 2 months might become January 14)
expect(result.getDate()).toBeGreaterThanOrEqual(14);
expect(result.getDate()).toBeLessThanOrEqual(15);
});
it("should handle year boundary", () => {
const baseDate = new Date("2024-01-15");
const result = subtractMonths(baseDate, 2);
expect(result.getFullYear()).toBe(2023);
expect(result.getMonth()).toBe(10); // November (0-indexed)
});
});
describe("isValidISODate", () => {
it("should validate correct ISO dates", () => {
expect(isValidISODate("2024-03-15")).toBe(true);
expect(isValidISODate("2024-12-31")).toBe(true);
expect(isValidISODate("2024-02-29")).toBe(true); // Leap year
});
it("should reject invalid formats", () => {
expect(isValidISODate("03/15/2024")).toBe(false);
expect(isValidISODate("2024-3-15")).toBe(false);
expect(isValidISODate("2024-03-5")).toBe(false);
expect(isValidISODate("24-03-15")).toBe(false);
expect(isValidISODate("not-a-date")).toBe(false);
});
it("should reject invalid dates with correct format", () => {
expect(isValidISODate("2024-02-30")).toBe(false); // Invalid date
expect(isValidISODate("2024-13-01")).toBe(false); // Invalid month
expect(isValidISODate("2023-02-29")).toBe(false); // Not a leap year
});
});
describe("isValidYNABMonth", () => {
it("should validate correct YNAB month format", () => {
expect(isValidYNABMonth("2024-03-01")).toBe(true);
expect(isValidYNABMonth("2024-12-01")).toBe(true);
});
it("should reject invalid formats", () => {
expect(isValidYNABMonth("2024-03-15")).toBe(false);
expect(isValidYNABMonth("2024-03")).toBe(false);
expect(isValidYNABMonth("03-01-2024")).toBe(false);
expect(isValidYNABMonth("not-a-month")).toBe(false);
});
it("should reject invalid months with correct format", () => {
expect(isValidYNABMonth("2024-13-01")).toBe(false); // Invalid month
expect(isValidYNABMonth("2024-00-01")).toBe(false); // Invalid month
});
});
describe("yearMonthToYNABMonth", () => {
it("should convert YYYY-MM to YYYY-MM-01", () => {
expect(yearMonthToYNABMonth("2024-03")).toBe("2024-03-01");
expect(yearMonthToYNABMonth("2024-12")).toBe("2024-12-01");
});
it("should throw error for invalid format", () => {
expect(() => yearMonthToYNABMonth("2024-3")).toThrow(
"Invalid year-month format",
);
expect(() => yearMonthToYNABMonth("24-03")).toThrow(
"Invalid year-month format",
);
expect(() => yearMonthToYNABMonth("not-valid")).toThrow(
"Invalid year-month format",
);
});
});
});
