CodeRabbit Generated Unit Tests: Add Jest testing setup with 6 test files and 325 tests

.gitignore

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 .DS_Store
+
+# Testing
+node_modules/
+coverage/
+.jest-cache/

package.json

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+{
+  "name": "battleship-game",
+  "version": "1.0.0",
+  "description": "Battleship game with comprehensive unit tests",
+  "type": "module",
+  "scripts": {
+    "test": "node --experimental-vm-modules node_modules/jest/bin/jest.js",
+    "test:watch": "node --experimental-vm-modules node_modules/jest/bin/jest.js --watch",
+    "test:coverage": "node --experimental-vm-modules node_modules/jest/bin/jest.js --coverage"
+  },
+  "jest": {
+    "testEnvironment": "jsdom",
+    "transform": {},
+    "extensionsToTreatAsEsm": [".js"],
+    "moduleNameMapper": {
+      "^(\\.{1,2}/.*)\\.js$": "$1"
+    },
+    "coveragePathIgnorePatterns": [
+      "/node_modules/",
+      "/__tests__/"
+    ],
+    "testMatch": [
+      "**/__tests__/**/*.test.js"
+    ]
+  },
+  "devDependencies": {
+    "jest": "^29.0.0",
+    "jest-environment-jsdom": "^29.0.0"
+  }
+}

src/__tests__/README.md

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+# Battleship Game Test Suite
+
+This directory contains comprehensive unit tests for all modules in the Battleship game.
+
+## Test Coverage
+
+### Core Modules
+- **constants.test.js** - Tests for game constants, ship definitions, and configuration
+- **ship.test.js** - Tests for Ship class including hit tracking and sinking logic
+- **board.test.js** - Tests for Board class including placement, attacks, and coordinate management
+- **ai-controller.test.js** - Tests for AI targeting logic and hunt/target strategy
+- **ui-controller.test.js** - Tests for UI rendering and DOM manipulation
+- **game.test.js** - Tests for main game controller and game flow
+
+## Running Tests
+
+```bash
+# Install dependencies (Jest)
+npm install
+
+# Run all tests
+npm test
+
+# Run tests in watch mode
+npm run test:watch
+
+# Run tests with coverage report
+npm run test:coverage
+```
+
+## Test Structure
+
+Each test file follows a consistent structure:
+- **Unit tests** for individual methods and functions
+- **Integration tests** for component interactions
+- **Edge case tests** for boundary conditions and error handling
+
+## Test Coverage Goals
+
+The test suite aims for:
+- High code coverage (>90%)
+- Comprehensive edge case testing
+- Clear, descriptive test names
+- Proper mocking of dependencies
+- Fast execution times
+
+## Notes
+
+- Tests use Jest with ES modules support
+- DOM manipulation is tested with jsdom environment
+- Mocks are created for UI controllers to isolate game logic
+- Random behavior is tested probabilistically