added streaks.test.js

Author: Aditya-Bajpayee007

package.json

@@ -7,19 +7,20 @@
     "@testing-library/jest-dom": "^6.9.1",
     "@testing-library/react": "^16.3.0",
     "@testing-library/user-event": "^13.5.0",
-    "date-fns": "^4.1.0",
     "framer-motion": "^12.23.22",
     "lucide-react": "^0.544.0",
     "react": "^19.2.0",
     "react-dom": "^19.2.0",
     "react-scripts": "5.0.1",
     "react-swipeable": "^7.0.2",
-    "web-vitals": "^2.1.4"
+    "web-vitals": "^2.1.4",
+    "date-fns": "^4.1.0"
   },
   "scripts": {
     "start": "react-scripts start",
     "build": "react-scripts build",
     "test": "react-scripts test",
+    "test:coverage": "react-scripts test --coverage",
     "eject": "react-scripts eject"
   },
   "eslintConfig": {
@@ -39,5 +40,15 @@
       "last 1 firefox version",
       "last 1 safari version"
     ]
+  },
+  "jest": {
+    "collectCoverageFrom": [
+      "src/hooks/useAchievements.js"
+    ],
+    "testMatch": [
+      "<rootDir>/src/**/__tests__/**/*.{js,jsx,ts,tsx}",
+      "<rootDir>/src/**/*.{spec,test}.{js,jsx,ts,tsx}",
+      "<rootDir>/tests/**/*.{spec,test}.{js,jsx,ts,tsx}"
+    ]
   }
 }

src/tests/streaks.test.js

@@ -0,0 +1,93 @@
+import {
+  calculateStreak,
+  checkAndAwardAchievements,
+} from "../hooks/useAchievements";
+
+describe("Streak and Achievement Tests (mocked dates)", () => {
+  const makeHabitWithDays = (numDays, achievements = []) => {
+    const completions = [];
+    const today = new Date();
+    today.setHours(0, 0, 0, 0);
+
+    for (let i = 0; i < numDays; i++) {
+      const d = new Date(today.getTime() - i * 24 * 60 * 60 * 1000);
+      completions.push(d);
+    }
+
+    return { completions, achievements };
+  };
+
+  describe("calculateStreak", () => {
+    test("empty completions → streak = 0", () => {
+      expect(calculateStreak({ completions: [], achievements: [] })).toBe(0);
+    });
+
+    test("single completion → streak = 1", () => {
+      expect(calculateStreak(makeHabitWithDays(1))).toBe(1);
+    });
+
+    test("consecutive 3-day streak", () => {
+      expect(calculateStreak(makeHabitWithDays(3))).toBe(3);
+    });
+
+    test("streak breaks with gap", () => {
+      const today = new Date();
+      today.setHours(0, 0, 0, 0);
+      const habit = {
+        completions: [
+          today,
+          new Date(today.getTime() - 24 * 60 * 60 * 1000),
+          new Date(today.getTime() - 3 * 24 * 60 * 60 * 1000),
+        ],
+        achievements: [],
+      };
+      expect(calculateStreak(habit)).toBe(2);
+    });
+
+    test("unordered completions still counted", () => {
+      const today = new Date();
+      today.setHours(0, 0, 0, 0);
+      const habit = {
+        completions: [new Date(today.getTime() - 24 * 60 * 60 * 1000), today],
+        achievements: [],
+      };
+      expect(calculateStreak(habit)).toBe(2);
+    });
+  });
+
+  describe("checkAndAwardAchievements", () => {
+    test("awards streak7 for 7-day streak", () => {
+      const habit = makeHabitWithDays(7);
+      const result = checkAndAwardAchievements(habit);
+      expect(result.achievements).toContain("streak7");
+      expect(result.newUnlocked).toContain("streak7");
+    });
+
+    test("awards streak30 for 30-day streak", () => {
+      const habit = makeHabitWithDays(30);
+      const result = checkAndAwardAchievements(habit);
+      expect(result.achievements).toContain("streak30");
+      expect(result.newUnlocked).toContain("streak30");
+    });
+
+    test("awards streak100 for 100-day streak", () => {
+      const habit = makeHabitWithDays(100);
+      const result = checkAndAwardAchievements(habit);
+      expect(result.achievements).toContain("streak100");
+      expect(result.newUnlocked).toContain("streak100");
+    });
+
+    test("does not re-award existing achievements", () => {
+      const habit = makeHabitWithDays(7, ["streak7"]);
+      const result = checkAndAwardAchievements(habit);
+      expect(result.achievements.filter((a) => a === "streak7").length).toBe(1);
+    });
+
+    test("handles habits with no completions safely", () => {
+      const habit = { completions: [], achievements: [] };
+      const result = checkAndAwardAchievements(habit);
+      expect(result.achievements).toEqual([]);
+      expect(result.newUnlocked).toEqual([]);
+    });
+  });
+});