test: Add comprehensive test suite with Vitest

- Install Vitest, @vitest/ui and @vitest/coverage-v8 for testing
- Create vitest.config.js with coverage configuration
- Add comprehensive test suite covering all BaziConverter methods
- Test normal cases, edge cases, and boundary conditions
- All 24 tests passing
- Remove sample.js (replaced by proper test suite)
- Update package.json scripts for test commands

Test coverage includes:
- Constructor validation
- Hour to Earth Number conversion
- TianGang and Dizi number formatting
- Bazi JSON output for various years (1930-2030)
- Unknown hour handling
- Chinese full string formatting
- English translation
- Elemental zodiac mapping

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

Author: gander

package.json

@@ -19,8 +19,11 @@
     "README.md"
   ],
   "scripts": {
+    "test": "vitest run",
+    "test:watch": "vitest",
+    "test:ui": "vitest --ui",
+    "test:coverage": "vitest run --coverage",
     "build": "echo \"Build not yet configured\"",
-    "test": "echo \"Tests not yet configured\"",
     "lint": "echo \"Biome not yet configured\"",
     "format": "echo \"Biome not yet configured\""
   },
@@ -58,5 +61,10 @@
   },
   "engines": {
     "node": ">=18.0.0"
+  },
+  "devDependencies": {
+    "@vitest/coverage-v8": "^4.0.15",
+    "@vitest/ui": "^4.0.15",
+    "vitest": "^4.0.15"
   }
 }

sample.js

@@ -0,0 +1,289 @@
+import { describe, it, expect } from 'vitest';
+import BaziConverter from '../BaziConverter.js';
+
+describe('BaziConverter', () => {
+  describe('Constructor', () => {
+    it('should create instance with valid date and hour', () => {
+      const bazi = new BaziConverter(1994, 5, 10, 21);
+      expect(bazi.year).toBe(1994);
+      expect(bazi.month).toBe(5);
+      expect(bazi.day).toBe(10);
+      expect(bazi.hour).toBe(21);
+    });
+  });
+
+  describe('getEarthNumberFromHour', () => {
+    it('should return correct earth number for valid hours', () => {
+      const bazi = new BaziConverter(2000, 1, 1, 0);
+
+      expect(bazi.getEarthNumberFromHour(0)).toBe('E1');   // 23-1
+      expect(bazi.getEarthNumberFromHour(23)).toBe('E1');  // 23-1
+      expect(bazi.getEarthNumberFromHour(1)).toBe('E2');   // 1-3
+      expect(bazi.getEarthNumberFromHour(3)).toBe('E3');   // 3-5
+      expect(bazi.getEarthNumberFromHour(5)).toBe('E4');   // 5-7
+      expect(bazi.getEarthNumberFromHour(7)).toBe('E5');   // 7-9
+      expect(bazi.getEarthNumberFromHour(9)).toBe('E6');   // 9-11
+      expect(bazi.getEarthNumberFromHour(11)).toBe('E7');  // 11-13
+      expect(bazi.getEarthNumberFromHour(13)).toBe('E8');  // 13-15
+      expect(bazi.getEarthNumberFromHour(15)).toBe('E9');  // 15-17
+      expect(bazi.getEarthNumberFromHour(17)).toBe('E10'); // 17-19
+      expect(bazi.getEarthNumberFromHour(19)).toBe('E11'); // 19-21
+      expect(bazi.getEarthNumberFromHour(21)).toBe('E12'); // 21-23
+    });
+
+    it('should return "-" for invalid hours', () => {
+      const bazi = new BaziConverter(2000, 1, 1, 0);
+      expect(bazi.getEarthNumberFromHour(-1)).toBe('-');
+      expect(bazi.getEarthNumberFromHour(-5)).toBe('-');
+    });
+  });
+
+  describe('convertToTianGangNumber', () => {
+    it('should convert number to TianGang format', () => {
+      const bazi = new BaziConverter(2000, 1, 1, 0);
+      expect(bazi.convertToTianGangNumber(1)).toBe('H1');
+      expect(bazi.convertToTianGangNumber(10)).toBe('H10');
+    });
+  });
+
+  describe('convertToDiziNumber', () => {
+    it('should convert number to Dizi format', () => {
+      const bazi = new BaziConverter(2000, 1, 1, 0);
+      expect(bazi.convertToDiziNumber(1)).toBe('E1');
+      expect(bazi.convertToDiziNumber(12)).toBe('E12');
+    });
+  });
+
+  describe('getBaziJson - Normal case with valid hour', () => {
+    it('should return correct bazi for 1994-05-10 21:00', () => {
+      const bazi = new BaziConverter(1994, 5, 10, 21);
+      const result = bazi.getBaziJson();
+
+      expect(result).toEqual({
+        year: '甲戌',
+        month: '己巳',
+        day: '丙申',
+        time: '己亥'
+      });
+    });
+
+    it('should return correct bazi for 2025-05-10 21:00', () => {
+      const bazi = new BaziConverter(2025, 5, 10, 21);
+      const result = bazi.getBaziJson();
+
+      expect(result).toEqual({
+        year: '乙巳',
+        month: '辛巳',
+        day: '己卯',
+        time: '乙亥'
+      });
+    });
+
+    it('should return correct bazi for 2030-05-10 21:00', () => {
+      const bazi = new BaziConverter(2030, 5, 10, 21);
+      const result = bazi.getBaziJson();
+
+      expect(result).toEqual({
+        year: '庚戌',
+        month: '辛巳',
+        day: '乙巳',
+        time: '丁亥'
+      });
+    });
+  });
+
+  describe('getBaziJson - Unknown hour case', () => {
+    it('should return "吉" for time when hour is invalid', () => {
+      const bazi = new BaziConverter(1993, 5, 10, -1);
+      const result = bazi.getBaziJson();
+
+      expect(result).toEqual({
+        year: '癸酉',
+        month: '丁巳',
+        day: '辛卯',
+        time: '吉'
+      });
+    });
+  });
+
+  describe('getBaziChineseFullString', () => {
+    it('should return full Chinese string format', () => {
+      const bazi = new BaziConverter(1994, 5, 10, 21);
+      const result = bazi.getBaziChineseFullString();
+
+      expect(result).toBe('甲戌年己巳月丙申日己亥时');
+    });
+
+    it('should handle unknown hour case', () => {
+      const bazi = new BaziConverter(1993, 5, 10, -1);
+      const result = bazi.getBaziChineseFullString();
+
+      expect(result).toBe('癸酉年丁巳月辛卯日吉时');
+    });
+  });
+
+  describe('translateBaziEnglish', () => {
+    it('should translate bazi to English for normal case', () => {
+      const bazi = new BaziConverter(1994, 5, 10, 21);
+      const result = bazi.translateBaziEnglish();
+
+      expect(result).toEqual({
+        year: 'Wood Dog',
+        month: 'Earth Snake',
+        day: 'Fire Monkey',
+        time: 'Earth Pig'
+      });
+    });
+
+    it('should handle unknown hour with "Lucky"', () => {
+      const bazi = new BaziConverter(1993, 5, 10, -1);
+      const result = bazi.translateBaziEnglish();
+
+      expect(result).toEqual({
+        year: 'Water Rooster',
+        month: 'Fire Snake',
+        day: 'Gold Rabbit',
+        time: 'Lucky '
+      });
+    });
+
+    it('should translate bazi for 2025 correctly', () => {
+      const bazi = new BaziConverter(2025, 5, 10, 21);
+      const result = bazi.translateBaziEnglish();
+
+      expect(result).toEqual({
+        year: 'Wood Snake',
+        month: 'Gold Snake',
+        day: 'Earth Rabbit',
+        time: 'Wood Pig'
+      });
+    });
+
+    it('should translate bazi for 2030 correctly', () => {
+      const bazi = new BaziConverter(2030, 5, 10, 21);
+      const result = bazi.translateBaziEnglish();
+
+      expect(result).toEqual({
+        year: 'Gold Dog',
+        month: 'Gold Snake',
+        day: 'Wood Snake',
+        time: 'Fire Pig'
+      });
+    });
+  });
+
+  describe('getBaziEnglishMapping', () => {
+    it('should map Chinese bazi to English element and animal', () => {
+      const bazi = new BaziConverter(1994, 5, 10, 21);
+      const result = bazi.getBaziEnglishMapping('甲戌');
+
+      expect(result).toEqual({
+        element: 'Wood',
+        animal_mnemonic: 'Dog'
+      });
+    });
+
+    it('should map different Chinese bazi correctly', () => {
+      const bazi = new BaziConverter(1994, 5, 10, 21);
+
+      expect(bazi.getBaziEnglishMapping('癸酉')).toEqual({
+        element: 'Water',
+        animal_mnemonic: 'Rooster'
+      });
+
+      expect(bazi.getBaziEnglishMapping('丁巳')).toEqual({
+        element: 'Fire',
+        animal_mnemonic: 'Snake'
+      });
+    });
+
+    // Note: Single character case is not handled by the second duplicate method (line 252)
+    // This is a known issue that should be fixed when removing duplicate methods
+  });
+
+  describe('getBaziJsonWithElementalZodiac', () => {
+    it('should return bazi with elemental zodiac mapping', () => {
+      const bazi = new BaziConverter(1994, 5, 10, 21);
+      const result = bazi.getBaziJsonWithElementalZodiac();
+
+      expect(result).toEqual({
+        year: '甲戌',
+        month: '己巳',
+        day: '丙申',
+        time: '己亥',
+        elemental_zodiac: {
+          year: '木狗',
+          month: '土蛇',
+          day: '火猴',
+          time: '土豬'
+        }
+      });
+    });
+
+    it('should handle unknown hour with "NA" for elemental zodiac', () => {
+      const bazi = new BaziConverter(1993, 5, 10, -1);
+      const result = bazi.getBaziJsonWithElementalZodiac();
+
+      expect(result).toEqual({
+        year: '癸酉',
+        month: '丁巳',
+        day: '辛卯',
+        time: '吉',
+        elemental_zodiac: {
+          year: '水雞',
+          month: '火蛇',
+          day: '金兔',
+          time: 'NA'
+        }
+      });
+    });
+  });
+
+  describe('getElementalZodiacMappingChinese', () => {
+    it('should convert English element+zodiac to Chinese', () => {
+      const bazi = new BaziConverter(1994, 5, 10, 21);
+      const result = bazi.getElementalZodiacMappingChinese('Wood Dog');
+
+      expect(result).toBe('木狗');
+    });
+
+    it('should return "NA" for "Lucky" time', () => {
+      const bazi = new BaziConverter(1993, 5, 10, -1);
+      const result = bazi.getElementalZodiacMappingChinese('Lucky ');
+
+      expect(result).toBe('NA');
+    });
+  });
+
+  describe('Edge cases and boundary testing', () => {
+    it('should handle midnight hour (0)', () => {
+      const bazi = new BaziConverter(2000, 1, 1, 0);
+      const result = bazi.getBaziJson();
+
+      expect(result.time).toBeDefined();
+      expect(typeof result.time).toBe('string');
+    });
+
+    it('should handle 23:00 hour', () => {
+      const bazi = new BaziConverter(2000, 1, 1, 23);
+      const result = bazi.getBaziJson();
+
+      expect(result.time).toBeDefined();
+      expect(typeof result.time).toBe('string');
+    });
+
+    it('should handle different years within data range', () => {
+      const years = [1930, 1950, 1970, 1990, 2000, 2010, 2020, 2030];
+
+      years.forEach(year => {
+        const bazi = new BaziConverter(year, 6, 15, 12);
+        const result = bazi.getBaziJson();
+
+        expect(result.year).toBeDefined();
+        expect(result.month).toBeDefined();
+        expect(result.day).toBeDefined();
+        expect(result.time).toBeDefined();
+      });
+    });
+  });
+});

tests/BaziConverter.test.js

@@ -0,0 +1,18 @@
+import { defineConfig } from 'vitest/config';
+
+export default defineConfig({
+  test: {
+    globals: true,
+    environment: 'node',
+    coverage: {
+      provider: 'v8',
+      reporter: ['text', 'json', 'html'],
+      exclude: [
+        'node_modules/',
+        'dist/',
+        'sample.js',
+        '*.config.js',
+      ],
+    },
+  },
+});