refactor(browser): log state transitions in debug (karma-runner#3202)

Author: johnjbarton

lib/browser.js

@@ -4,11 +4,11 @@ const BrowserResult = require('./browser_result')
 const helper = require('./helper')
 const logger = require('./logger')
 
-const CONNECTED = 1 // The browser is connected but not yet been commanded to execute tests.
-const CONFIGURING = 2 // The browser has been told to execute tests; it is configuring before tests execution.
-const EXECUTING = 3 // The browser is executing the tests.
-const EXECUTING_DISCONNECTED = 4 // The browser is executing the tests, but temporarily disconnect (waiting for reconnecting).
-const DISCONNECTED = 5 // The browser got permanently disconnected (being removed from the collection and destroyed).
+const CONNECTED = 'CONNECTED' // The browser is connected but not yet been commanded to execute tests.
+const CONFIGURING = 'CONFIGURING' // The browser has been told to execute tests; it is configuring before tests execution.
+const EXECUTING = 'EXECUTING' // The browser is executing the tests.
+const EXECUTING_DISCONNECTED = 'EXECUTING_DISCONNECTED' // The browser is executing the tests, but temporarily disconnect (waiting for reconnecting).
+const DISCONNECTED = 'DISCONNECTED' // The browser got permanently disconnected (being removed from the collection and destroyed).
 
 class Browser {
   constructor (id, fullName, collection, emitter, socket, timer, disconnectDelay, noActivityTimeout) {
@@ -40,6 +40,11 @@ class Browser {
     this.emitter.emit('browser_register', this)
   }
 
+  setState (toState) {
+    this.log.debug(`${this.state} -> ${toState}`)
+    this.state = toState
+  }
+
   onKarmaError (error) {
     if (this.isNotConnected()) {
       this.lastResult.error = true
@@ -70,14 +75,14 @@ class Browser {
     }
 
     this.lastResult = new BrowserResult(info.total)
-    this.state = EXECUTING
+    this.setState(EXECUTING)
     this.emitter.emit('browser_start', this, info)
     this.refreshNoActivityTimeout()
   }
 
   onComplete (result) {
     if (this.isNotConnected()) {
-      this.state = CONNECTED
+      this.setState(CONNECTED)
       this.lastResult.totalTimeEnd()
 
       if (!this.lastResult.success) {
@@ -103,7 +108,7 @@ class Browser {
       this.disconnect(`Client disconnected from CONNECTED state (${reason})`)
     } else if ([CONFIGURING, EXECUTING].includes(this.state)) {
       this.log.debug(`Disconnected during run, waiting ${this.disconnectDelay}ms for reconnecting.`)
-      this.state = EXECUTING_DISCONNECTED
+      this.setState(EXECUTING_DISCONNECTED)
 
       this.pendingDisconnect = this.timer.setTimeout(() => {
         this.lastResult.totalTimeEnd()
@@ -119,12 +124,12 @@ class Browser {
   reconnect (newSocket) {
     if (this.state === EXECUTING_DISCONNECTED) {
       this.log.debug(`Reconnected on ${newSocket.id}.`)
-      this.state = EXECUTING
+      this.setState(EXECUTING)
     } else if ([CONNECTED, CONFIGURING, EXECUTING].includes(this.state)) {
       this.log.debug(`New connection ${newSocket.id} (already have ${this.getActiveSocketsIds()})`)
     } else if (this.state === DISCONNECTED) {
       this.log.info(`Connected on socket ${newSocket.id} with id ${this.id}`)
-      this.state = CONNECTED
+      this.setState(CONNECTED)
 
       this.collection.add(this)
       this.emitter.emit('browser_register', this)
@@ -155,7 +160,7 @@ class Browser {
 
   execute (config) {
     this.activeSockets.forEach((socket) => socket.emit('execute', config))
-    this.state = CONFIGURING
+    this.setState(CONFIGURING)
     this.refreshNoActivityTimeout()
   }
 
@@ -165,7 +170,7 @@ class Browser {
 
   disconnect (reason) {
     this.log.warn(`Disconnected (${this.disconnectsCount} times)${reason || ''}`)
-    this.state = DISCONNECTED
+    this.setState(DISCONNECTED)
     this.disconnectsCount++
     this.emitter.emit('browser_error', this, `Disconnected${reason || ''}`)
     this.collection.remove(this)