✅ add unit testing for helper functions

src/utils/helpers.test.ts

@@ -0,0 +1,158 @@
+import { Round } from '../models/round';
+import {
+  calculateRanking,
+  calculateRoundResultsHistory,
+  formatDateTime,
+  formatNumber,
+  getColor,
+  getSum,
+  getSummaryText,
+} from './helpers';
+
+describe('Utility functions', () => {
+  describe('getColor', () => {
+    it('should return "green" for positive numbers', () => {
+      expect(getColor(5)).toBe('green');
+    });
+    it('should return "red" for negative numbers', () => {
+      expect(getColor(-5)).toBe('red');
+    });
+    it('should return an empty string for zero', () => {
+      expect(getColor(0)).toBe('grey');
+    });
+  });
+
+  describe('formatNumber', () => {
+    it('should add "+" for positive numbers', () => {
+      expect(formatNumber(5)).toBe('+5');
+    });
+    it('should not add "+" for negative numbers', () => {
+      expect(formatNumber(-5)).toBe('-5');
+    });
+    it('should display "0" without a sign', () => {
+      expect(formatNumber(0)).toBe('0');
+    });
+  });
+
+  describe('getSum', () => {
+    it('should return the sum of numbers in an array', () => {
+      expect(getSum([1, 2, 3])).toBe(6);
+    });
+    it('should handle an empty array', () => {
+      expect(getSum([])).toBe(0);
+    });
+    it('should handle negative numbers', () => {
+      expect(getSum([-1, -2, -3])).toBe(-6);
+    });
+  });
+
+  describe('formatDateTime', () => {
+    it('should format timestamp correctly', () => {
+      const timestamp = new Date('1996-11-26T23:45:00').getTime();
+      expect(formatDateTime(timestamp)).toBe('26-11-1996 23:45');
+    });
+  });
+});
+
+describe('Main functions with multiple balanced rounds', () => {
+  const rounds: Round[] = [
+    {
+      id: '1',
+      gameId: 'g1',
+      timestamp: 1000,
+      stats: { Alice: 10, Bob: -5, Carol: -5 },
+    },
+    {
+      id: '2',
+      gameId: 'g1',
+      timestamp: 2000,
+      stats: { Alice: -10, Bob: 10, Carol: 0 },
+    },
+    {
+      id: '3',
+      gameId: 'g1',
+      timestamp: 3000,
+      stats: { Alice: 5, Bob: -10, Carol: 5 },
+    },
+    {
+      id: '4',
+      gameId: 'g1',
+      timestamp: 4000,
+      stats: { Alice: 0, Bob: 15, Carol: -15 },
+    },
+    {
+      id: '5',
+      gameId: 'g1',
+      timestamp: 5000,
+      stats: { Alice: -5, Bob: -5, Carol: 10 },
+    },
+    {
+      id: '6',
+      gameId: 'g1',
+      timestamp: 6000,
+      stats: { Alice: 15, Bob: -15, Carol: 0 },
+    },
+    {
+      id: '7',
+      gameId: 'g1',
+      timestamp: 7000,
+      stats: { Alice: -10, Bob: 0, Carol: 10 },
+    },
+    {
+      id: '8',
+      gameId: 'g1',
+      timestamp: 8000,
+      stats: { Alice: 5, Bob: 5, Carol: -10 },
+    },
+    {
+      id: '9',
+      gameId: 'g1',
+      timestamp: 9000,
+      stats: { Alice: -5, Bob: 10, Carol: -5 },
+    },
+    {
+      id: '10',
+      gameId: 'g1',
+      timestamp: 10000,
+      stats: { Alice: 10, Bob: -10, Carol: 0 },
+    },
+  ];
+  const playerNames = ['Alice', 'Bob', 'Carol'];
+
+  describe('calculateRoundResultsHistory with 10 balanced rounds', () => {
+    it('should calculate cumulative round results accurately for each player', () => {
+      const result = calculateRoundResultsHistory(rounds, playerNames);
+      expect(result).toEqual({
+        Alice: [0, 10, 0, 5, 5, 0, 15, 5, 10, 5, 15],
+        Bob: [0, -5, 5, -5, 10, 5, -10, -10, -5, 5, -5],
+        Carol: [0, -5, -5, 0, -15, -5, -5, 5, -5, -10, -10],
+      });
+    });
+  });
+
+  describe('calculateRanking with 10 balanced rounds', () => {
+    it('should calculate correct ranking based on the latest cumulative scores', () => {
+      const roundResultHistory = calculateRoundResultsHistory(
+        rounds,
+        playerNames,
+      );
+      const result = calculateRanking(roundResultHistory);
+      expect(result).toEqual([
+        { name: 'Alice', stat: 15 },
+        { name: 'Bob', stat: -5 },
+        { name: 'Carol', stat: -10 },
+      ]);
+    });
+  });
+
+  describe('getSummaryText with 10 balanced rounds', () => {
+    it('should return a formatted summary text for the final ranking', () => {
+      const roundResultHistory = calculateRoundResultsHistory(
+        rounds,
+        playerNames,
+      );
+      const ranking = calculateRanking(roundResultHistory);
+      expect(getSummaryText(ranking)).toBe('Alice: +15\nBob: -5\nCarol: -10\n');
+    });
+  });
+});