Adding some unit tests

package.json

@@ -11,7 +11,8 @@
     "watch:start": "nodemon --exec npm run start",
     "dev": "concurrently -n build,start \"npm run watch:build\" \"npm run watch:start\"",
     "dev:full": "concurrently -n client,server -c yellow,green \"npm run dev\" \"cd client && npm run dev\"",
-    "test": "jest"
+    "test": "jest",
+    "test:watch": "jest --watch"
   },
   "contributors": [
     "Protectator",

server/display.test.ts

@@ -0,0 +1,17 @@
+import {Display} from "./display";
+import {HtmlColors} from "./htmlColors";
+
+const DISPLAY_SIZE = 100;
+
+function generateTestDisplay() {
+  return new Display(DISPLAY_SIZE, "", 13335, false);
+}
+
+const FULL_BLACK = Array(DISPLAY_SIZE).fill(HtmlColors.black);
+
+describe('Display', () => {
+  test("is fully black at creation", () => {
+    const display = generateTestDisplay();
+    expect(display.screenshot()).toStrictEqual(FULL_BLACK);
+  });
+})

server/display.ts

@@ -104,12 +104,6 @@ export class Display {
   }
 
   private newBlackArray(length: number): Color[] {
-    const arr: Color[] = [];
-
-    for (let i = 0; i < length; i++) {
-      arr[i] = HtmlColors.black;
-    }
-
-    return arr;
+    return Array(length).fill(HtmlColors.black);
   }
 }

server/game.test.ts

@@ -1,6 +1,7 @@
-import { Game } from "./game";
-import { Display } from "./display";
-import { GameOptions } from "./types/GameOptions";
+import {Game} from "./game";
+import {Display} from "./display";
+import {GameOptions} from "./types/GameOptions";
+import {Color} from "./color";
 
 const gameOptions: GameOptions = {
   BattleRoyale: {
@@ -23,8 +24,51 @@ const gameOptions: GameOptions = {
   },
 };
 
-test("Game is created correctly", () => {
-  const display: Display = new Display(100, "", 13335, false);
+const INITIAL_STATE = {
+  characters: [
+    {
+      alive: true,
+      color: new Color(255, 0, 0, 0),
+      facesRight: true,
+      id: 0,
+      shotCooldown: 0,
+      shotRange: 18,
+      x: 0,
+    },
+    {
+      alive: true,
+      color: new Color(0, 255, 255, 0),
+      facesRight: true,
+      id: 1,
+      shotCooldown: 0,
+      shotRange: 18,
+      x: 50,
+    }
+  ],
+  shots: [],
+  turnNb: 0,
+};
+
+function generateTestDisplayAndGame() {
+  const display = new Display(100, "", 13335, false);
   const game = new Game(20, 2, display, gameOptions);
-  expect(game.newInputs.length).toBe(0);
-});
+  return {display, game};
+}
+
+const FAKE_DATE = new Date('2020-01-01');
+
+describe('Game', () => {
+  beforeEach(() => {
+    jest
+      .useFakeTimers()
+      .setSystemTime(FAKE_DATE);
+  });
+
+  test("is created correctly", () => {
+    const {game} = generateTestDisplayAndGame();
+    expect(game.newInputs.length).toBe(0);
+    expect(game.gameState).toStrictEqual({
+      ...INITIAL_STATE, startDate: FAKE_DATE,
+    });
+  });
+})

server/htmlColors.ts

@@ -145,4 +145,4 @@ export const HtmlColors = {
   gainsboro: new Color(220, 220, 220),
   whitesmoke: new Color(245, 245, 245),
   white: new Color(255, 255, 255),
-};
+} as const;