From 2ed1ee3d4781a6665038a1ea08f05538889a7fe6 Mon Sep 17 00:00:00 2001
From: Arvin Liu <arvin7liu@users.noreply.github.com>
Date: Sat, 22 Aug 2026 01:43:49 +0800
Subject: [PATCH] test(node-js): add unit tests for controller command logic;
 fix DriveValue.read rounding

- Add controller/node-js/test/commands.test.js covering CommandHandler drive
  mapping, DriveCommandReducer de-duplication, and DriveValue bounds.
- Fix DriveValue.read(): Math.round(value, 3) ignored the 2nd argument and
  returned an integer; use Math.round(value * 1000) / 1000 for 3-decimal
  precision. Export DriveValue so it is testable.
- Add "test": "node --test" script (zero new dependencies, runs on Node 18+).
---
 controller/node-js/package.json          |  3 +-
 controller/node-js/server/commands.js    |  4 +-
 controller/node-js/test/commands.test.js | 97 ++++++++++++++++++++++++
 3 files changed, 101 insertions(+), 3 deletions(-)
 create mode 100644 controller/node-js/test/commands.test.js

diff --git a/controller/node-js/package.json b/controller/node-js/package.json
index 6911cc383..5857eb9a7 100644
--- a/controller/node-js/package.json
+++ b/controller/node-js/package.json
@@ -10,7 +10,8 @@
     "dev:server": "npm run start --prefix server",
     "dev:start-client": "vite --port 8081 --host",
     "build": "vite build",
-    "lint": "eslint server/*.js --fix && eslint client/*.js --fix"
+    "lint": "eslint server/*.js --fix && eslint client/*.js --fix",
+    "test": "node --test"
   },
   "author": "Ivo Zivkov",
   "devDependencies": {
diff --git a/controller/node-js/server/commands.js b/controller/node-js/server/commands.js
index eb047acc6..737385aa3 100644
--- a/controller/node-js/server/commands.js
+++ b/controller/node-js/server/commands.js
@@ -42,7 +42,7 @@ function DriveValue () {
   }
 
   this.read = () => {
-    return Math.round(value, 3)
+    return Math.round(value * 1000) / 1000
   }
 }
 
@@ -121,4 +121,4 @@ function DriveCommandReducer () {
   }
 }
 
-module.exports = { Commands, CommandHandler }
+module.exports = { Commands, CommandHandler, DriveValue }
diff --git a/controller/node-js/test/commands.test.js b/controller/node-js/test/commands.test.js
new file mode 100644
index 000000000..85d05e501
--- /dev/null
+++ b/controller/node-js/test/commands.test.js
@@ -0,0 +1,97 @@
+/*
+ * Unit tests for the OpenBot node-js controller command logic.
+ *
+ * These exercise the pure server-side command mapping that ultimately drives
+ * the robot's left/right motors, so a regression here could send wrong motor
+ * commands. Run with: `npm test` (uses Node's built-in test runner).
+ */
+
+const test = require('node:test')
+const assert = require('node:assert')
+
+const { Commands, DriveValue } = require('../server/commands.js')
+
+// Creates a CommandHandler and captures every command string it sends.
+function makeHandler () {
+  const sent = []
+  const commands = new Commands(msg => sent.push(msg))
+  return { handler: commands.getCommandHandler(), sent }
+}
+
+test('goForward sends full forward drive command', () => {
+  const { handler, sent } = makeHandler()
+  handler.goForward()
+  assert.deepStrictEqual(JSON.parse(sent[0]), { driveCmd: { l: 1, r: 1 } })
+})
+
+test('goBackward sends full reverse drive command', () => {
+  const { handler, sent } = makeHandler()
+  handler.goBackward()
+  assert.deepStrictEqual(JSON.parse(sent[0]), { driveCmd: { l: -1, r: -1 } })
+})
+
+test('forwardLeft mixes left/right correctly', () => {
+  const { handler, sent } = makeHandler()
+  handler.forwardLeft()
+  assert.deepStrictEqual(JSON.parse(sent[0]), { driveCmd: { l: -0.5, r: 1 } })
+})
+
+test('forwardRight mixes right/left correctly', () => {
+  const { handler, sent } = makeHandler()
+  handler.forwardRight()
+  assert.deepStrictEqual(JSON.parse(sent[0]), { driveCmd: { l: 1, r: -0.5 } })
+})
+
+test('rotateLeft / rotateRight send opposing wheel commands', () => {
+  const { handler, sent } = makeHandler()
+  handler.rotateLeft()
+  assert.deepStrictEqual(JSON.parse(sent[0]), { driveCmd: { l: -1, r: 1 } })
+
+  const { handler: handler2, sent: sent2 } = makeHandler()
+  handler2.rotateRight()
+  assert.deepStrictEqual(JSON.parse(sent2[0]), { driveCmd: { l: 1, r: -1 } })
+})
+
+test('reset sends a zero drive command', () => {
+  const { handler, sent } = makeHandler()
+  handler.reset()
+  assert.deepStrictEqual(JSON.parse(sent[0]), { driveCmd: { l: 0, r: 0 } })
+})
+
+test('consecutive identical drive commands are de-duplicated', () => {
+  const { handler, sent } = makeHandler()
+  handler.goForward()
+  handler.goForward()
+  handler.goForward()
+  assert.strictEqual(sent.length, 1)
+})
+
+test('different drive commands are each sent', () => {
+  const { handler, sent } = makeHandler()
+  handler.goForward()
+  handler.goBackward()
+  assert.strictEqual(sent.length, 2)
+})
+
+test('sendCommand forwards the raw command string', () => {
+  const { handler, sent } = makeHandler()
+  handler.sendCommand('NOISE')
+  assert.strictEqual(sent[0], '{command: NOISE }')
+})
+
+test('DriveValue clamps to [-1, 1] and read() rounds to 3 decimals', () => {
+  const dv = new DriveValue()
+  assert.strictEqual(dv.reset(), 0)
+  assert.strictEqual(dv.min(), -1)
+  assert.strictEqual(dv.max(), 1)
+
+  // Before the fix this returned Math.round(0.12345) === 0 (2nd arg ignored).
+  dv.write(0.12345)
+  assert.strictEqual(dv.read(), 0.123)
+
+  dv.write(0.9999)
+  assert.strictEqual(dv.read(), 1)
+
+  dv.write(-0.4567)
+  assert.strictEqual(dv.read(), -0.457)
+})