Заменил кастомные тесты на Jest

.gitignore

@@ -1 +1,2 @@
-node_modules
+node_modules
+coverage

README.md

@@ -19,13 +19,16 @@ npm install
 npm start
 ```
 ## Запуск тестов
-На текущий момент не используем каких-то стороних тест-раннеров. Тесты запускаем нодой, а тестируем стандартным нодовским assert.
-Так как тест это es6 module, версия ноды должна быть не меньше 13. Сам запускал на v16.13.2.
-Запустить тест можно командой:
+Unit-тестируем calculator.js, потому что там лежит вся "бизнес-логика" нашего калькулятора демонения.
 ```
 npm test
 ```
 
+Чтобы посмотреть с code coverage:
+```
+npm run test:run
+```
+
 ## Формула демонения
 Количество созданных существ определяется здоровьем убитого отряда и количеством "Питов". 
 

jest.config.json

@@ -0,0 +1,4 @@
+{
+    "coverageDirectory": "./coverage",
+    "collectCoverageFrom": ["src/js/calculator.js"]
+}

package.json

@@ -1,12 +1,17 @@
 {
     "name": "heroes3-demonology",
     "version": "0.1.0",
+    "type": "module",
     "devDependencies": {
-        "serve": "^13.0.2"
+        "serve": "14.2.1",
+        "jest": "29.7.0",
+        "prettier": "3.0.3",
+        "serve": "13.0.2"
     },
-    "type": "module",
     "scripts": {
         "start": "serve ./src",
-        "test": "node ./test/calc_test.js"
+        "jest": "node --experimental-vm-modules node_modules/jest/bin/jest.js",
+        "test": "npm run jest -- --watch",
+        "test:run": "npm run jest -- --coverage"
     }
-}
+}

src/js/calculator.js

@@ -38,4 +38,4 @@ const getOptimalHealth = function (overallHealth) {
     return overallHealth - leftovers;
 }
 
-export default { getDemonsNumber: getDemonsNumber, getOptimalNumber: getOptimalNumber };
+export default { getDemonsNumber, getOptimalNumber };

src/js/calculator.test.js

@@ -0,0 +1,108 @@
+import { test, describe, expect } from "@jest/globals";
+import calc from "./calculator.js";
+
+const testData = [
+    {
+        name: "3 pitlords and 15 imps",
+        data: [3, 15, 4],
+        expectedDemonsNumber: 1,
+        expectedOptimalNumber: 9
+    },
+    {
+        name: "demons into demons",
+        data: [3, 5, 35],
+        expectedDemonsNumber: 4,
+        expectedOptimalNumber: 4
+    },
+    {
+        name: "Case when demons by pitlords is BIGGER then by creatures",
+        data: [25, 100, 4],
+        expectedDemonsNumber: 11,
+        expectedOptimalNumber: 97
+    },
+    {
+        name: "Case when demons by pitlords is LESS then demons by creatures",
+        data: [4, 100, 4],
+        expectedDemonsNumber: 5,
+        expectedOptimalNumber: 44
+    },
+    {
+        name: "Check that demons is does not more than creatures",
+        data: [10, 5, 80],
+        expectedDemonsNumber: 5,
+        expectedOptimalNumber: 5
+    },
+    {
+        name: "Case when creatures is not enough for one demon",
+        data: [10, 11, 3],
+        expectedDemonsNumber: 0,
+        expectedOptimalNumber: 0
+    },
+    {
+        name: "Case when creatures is just enough for one demon",
+        data: [10, 7, 5],
+        expectedDemonsNumber: 1,
+        expectedOptimalNumber: 7
+    },
+    {
+        name: "Creatures a little bit more for one demon",
+        data: [10, 36, 1],
+        expectedDemonsNumber: 1,
+        expectedOptimalNumber: 35
+    },
+    {
+        name: "Creatures a little bit more for one demon",
+        data: [10, 36, 1],
+        expectedDemonsNumber: 1,
+        expectedOptimalNumber: 35
+    },
+    {
+        name: "All zeroes",
+        data: [0, 0, 0],
+        expectedDemonsNumber: 0,
+        expectedOptimalNumber: 0
+    },
+    {
+        name: "Zero pitlords",
+        data: [0, 10, 10],
+        expectedDemonsNumber: 0,
+        expectedOptimalNumber: 0
+    },
+    {
+        name: "Zero creatures",
+        data: [10, 0, 10],
+        expectedDemonsNumber: 0,
+        expectedOptimalNumber: 0
+    },
+    {
+        name: "Zero creature hp",
+        data: [10, 10, 0],
+        expectedDemonsNumber: 0,
+        expectedOptimalNumber: 0
+    },
+    {
+        name: "A lot of everything",
+        data: [9999, 9999, 9999],
+        expectedDemonsNumber: 9999,
+        expectedOptimalNumber: 9999
+    },
+    {
+        name: "Passing Strings",
+        data: ["10", "36", "1"],
+        expectedDemonsNumber: 1,
+        expectedOptimalNumber: 35
+    },
+];
+
+describe.each(testData)("getDemonsNumber()",
+    ({ name, data, expectedDemonsNumber }) => test(name, () =>
+        expect(calc.getDemonsNumber(...data)).toBe(expectedDemonsNumber)
+    )
+);
+
+describe.each(testData)("getOptimalDemonsNumber()",
+    ({ name, data, expectedDemonsNumber, expectedOptimalNumber }) =>
+        test(name, () =>
+            expect(calc.getOptimalNumber(...data, expectedDemonsNumber)).toBe(expectedOptimalNumber)
+        )
+);