chinese-days/test/solar_terms/index.test.ts

import dayjs from "../../src/utils/dayjs";
import { getSolarTermDate, getSolarTerms, getSolarTermsInRange, type SolarTerm } from "../../src";

import type { SolarTermKey } from "../../src/solar_terms/constants";

describe("Solar Terms", () => {
  describe("getSolarTermDate", () => {
    it("should correctly calculate the solar term date for 'lesser_cold' in 1998", () => {
      const term: SolarTermKey = "lesser_cold";
      const date = getSolarTermDate(1998, 1, term);
      expect(date).toBe("1998-01-05");
    });

    it("should correctly calculate the solar term date for 'lesser_cold' in 2024", () => {
      const term: SolarTermKey = "lesser_cold";
      const date = getSolarTermDate(2024, 1, term);
      expect(date).toBe("2024-01-06");
    });

    it("should correctly calculate the solar term date for 'rain_water' in 2026 with delta adjustment", () => {
      const term: SolarTermKey = "rain_water";
      const date = getSolarTermDate(2026, 2, term);
      expect(date).toBe("2026-02-18");
    });

    it("should handle the case where there is no delta adjustment", () => {
      const term: SolarTermKey = "the_beginning_of_spring";
      const date = getSolarTermDate(2024, 2, term);
      expect(date).toBe("2024-02-04");
    });
  });

  describe("getSolarTerms", () => {
    it("should return the solar terms within the date range in 2024", () => {
      const start = dayjs("2024-01-01");
      const end = dayjs("2024-02-29");
      const terms = getSolarTerms(start, end);
      const expected: SolarTerm[] = [
        { date: "2024-01-06", term: "lesser_cold", name: "小寒", index: 1 },
        { date: "2024-01-20", term: "greater_cold", name: "大寒", index: 1 },
        {
          date: "2024-02-04",
          term: "the_beginning_of_spring",
          name: "立春",
          index: 1,
        },
        { date: "2024-02-19", term: "rain_water", name: "雨水", index: 1 },
      ];
      expect(terms).toEqual(expected);
    });

    it("should return an empty array if no solar terms fall within the date range", () => {
      const start = dayjs("2024-03-01");
      const end = dayjs("2024-03-31");
      const terms = getSolarTerms(start, end);
      expect(terms).toEqual([
        {
          date: "2024-03-05",
          name: "惊蛰",
          term: "the_waking_of_insects",
          index: 1,
        },
        {
          date: "2024-03-20",
          name: "春分",
          term: "the_spring_equinox",
          index: 1,
        },
      ]);
    });

    it("should handle a single day range", () => {
      const date = dayjs("2024-01-06");
      const terms = getSolarTerms(date, date);
      const expected: SolarTerm[] = [
        { date: "2024-01-06", term: "lesser_cold", name: "小寒", index: 1 },
      ];
      expect(terms).toEqual(expected);
    });

    it("should handle a single day range", () => {
      const date = dayjs("2024-01-06");
      const terms = getSolarTerms(date);
      const expected: SolarTerm[] = [
        { date: "2024-01-06", term: "lesser_cold", name: "小寒", index: 1 },
      ];
      expect(terms).toEqual(expected);
    });
  });

  describe('getSolarTermsInRange', () => {
    test('should get solar terms within the specified date range', () => {
      const start = dayjs('2024-01-04');
      const end = dayjs('2024-01-07');
  
      const result = getSolarTermsInRange(start, end);
      expect(result).toEqual([
        {
          date: '2024-01-04',
          term: 'the_winter_solstice',
          name: '冬至',
          index: 14
        },
        {
          date: '2024-01-05',
          term: 'the_winter_solstice',
          name: '冬至',
          index: 15
        },
        { date: '2024-01-06', term: 'lesser_cold', name: '小寒', index: 1 },
        { date: '2024-01-07', term: 'lesser_cold', name: '小寒', index: 2 }
      ]);
    });
  
    test('should get solar terms for the current day when end date is not provided', () => {
      const start = dayjs('2024-01-20');
  
      const result = getSolarTermsInRange(start);
  
      expect(result).toEqual([{ date: '2024-01-20', term: 'greater_cold', name: '大寒', index: 1 }]);
    });
  
    test('should handle date range spanning across the year boundary', () => {
      const start = dayjs('2024-12-30');
      const end = dayjs('2025-01-02');
  
      const result = getSolarTermsInRange(start, end);
  
      expect(result).toEqual([
        {
          date: '2024-12-30',
          term: 'the_winter_solstice',
          name: '冬至',
          index: 10
        },
        {
          date: '2024-12-31',
          term: 'the_winter_solstice',
          name: '冬至',
          index: 11
        },
        {
          date: '2025-01-01',
          term: 'the_winter_solstice',
          name: '冬至',
          index: 12
        },
        {
          date: '2025-01-02',
          term: 'the_winter_solstice',
          name: '冬至',
          index: 13
        }
      ]);
    });
  });
});