FIX - stabilize phone game engines

frontend/src/features/games/neon-drop/engine.test.ts

@@ -20,6 +20,10 @@ describe('neon drop engine', () => {
   it('starts with a valid piece and a complete seven-piece bag', () => {
     const game = createNeonDropGame(() => 0.5)
     expect(game.status).toBe('playing')
+    expect(game.board).toHaveLength(17)
+    expect(game.board.every((row) => row.length === NEON_DROP_COLUMNS)).toBe(
+      true,
+    )
     expect(new Set([game.active.kind, ...game.queue]).size).toBe(7)
     expect(canPlaceNeonDropPiece(game.board, game.active)).toBe(true)
   })

frontend/src/features/games/neon-drop/engine.ts

@@ -8,7 +8,7 @@ import type {
 } from './types'
 
 export const NEON_DROP_COLUMNS = 10
-export const NEON_DROP_ROWS = 18
+export const NEON_DROP_ROWS = 17
 export const NEON_DROP_LINES_PER_LEVEL = 8
 
 const PIECE_KINDS: NeonDropPieceKind[] = ['I', 'J', 'L', 'O', 'S', 'T', 'Z']

frontend/src/features/games/snake/engine.test.ts

@@ -2,6 +2,7 @@ import { describe, expect, it } from 'vitest'
 
 import {
   createSnakeGame,
+  SNAKE_BOARD_HEIGHT,
   SNAKE_BOARD_WIDTH,
   stepSnake,
   turnSnake,
@@ -27,6 +28,17 @@ describe('Snake engine', () => {
     expect(next.body).not.toContainEqual(next.fruit)
   })
 
+  it('places fruit inside the visible play area', () => {
+    for (const random of [() => 0, () => 1]) {
+      const { fruit } = createSnakeGame(random)
+
+      expect(fruit.x).toBeGreaterThanOrEqual(0)
+      expect(fruit.x).toBeLessThan(SNAKE_BOARD_WIDTH)
+      expect(fruit.y).toBeGreaterThanOrEqual(0)
+      expect(fruit.y).toBeLessThan(SNAKE_BOARD_HEIGHT)
+    }
+  })
+
   it('ignores an immediate reverse direction', () => {
     const game = createSnakeGame(() => 0)
 
@@ -46,6 +58,20 @@ describe('Snake engine', () => {
     expect(stepSnake(game).status).toBe('game-over')
   })
 
+  it('ends the game at the lower edge of the visible play area', () => {
+    const game: SnakeGameState = {
+      ...createSnakeGame(() => 0),
+      body: [
+        { x: 4, y: SNAKE_BOARD_HEIGHT - 1 },
+        { x: 4, y: SNAKE_BOARD_HEIGHT - 2 },
+      ],
+      direction: 'down',
+      pendingDirection: 'down',
+    }
+
+    expect(stepSnake(game).status).toBe('game-over')
+  })
+
   it('ends the game on body collision', () => {
     const game: SnakeGameState = {
       body: [

frontend/src/features/games/snake/engine.ts

@@ -5,7 +5,7 @@ import type {
 } from './types'
 
 export const SNAKE_BOARD_WIDTH = 16
-export const SNAKE_BOARD_HEIGHT = 18
+export const SNAKE_BOARD_HEIGHT = 30
 
 const DIRECTION_VECTORS: Record<SnakeDirection, SnakePoint> = {
   up: { x: 0, y: -1 },