fix: Return correct exit code when server fails to start

src/child-process.coffee

@@ -118,6 +118,7 @@ terminate = (childProcess, options = {}, callback) ->
 spawn = (args...) ->
   childProcess = crossSpawn.spawn.apply(null, args)
 
+  childProcess.spawned = true
   childProcess.terminated = false
   killedIntentionally = false
   terminatedIntentionally = false
@@ -140,6 +141,12 @@ spawn = (args...) ->
       childProcess.emit('error', err) if err
     )
 
+  childProcess.on('error', (err) ->
+    if err.syscall.indexOf('spawn') >= 0
+      childProcess.spawned = false
+      childProcess.emit('spawnerror', err)
+  )
+
   childProcess.on('exit', (exitStatus, signal) ->
     childProcess.terminated = true
     childProcess.killedIntentionally = killedIntentionally

src/dredd-command.coffee

@@ -53,7 +53,7 @@ class DreddCommand
 
   # Gracefully terminate server
   stopServer: (callback) ->
-    unless @serverProcess?
+    if not @serverProcess or not @serverProcess.spawned
       logger.verbose('No backend server process to terminate.')
       return callback()
     if @serverProcess.terminated
@@ -219,9 +219,9 @@ class DreddCommand
       @serverProcess.on 'exit', =>
         logger.info('Backend server process exited')
 
-      @serverProcess.on 'error', (error) =>
-        logger.error('Command to start backend server process failed, exiting Dredd', error)
-        @_processExit(2)
+      @serverProcess.on 'spawnerror', (err) =>
+        logger.error('Command to start backend server process failed, exiting Dredd', err)
+        @_processExit(1)
 
       # Ensure server is not running when dredd exits prematurely somewhere
       process.on 'beforeExit', =>
@@ -332,11 +332,9 @@ class DreddCommand
   exitWithStatus: (error, stats) ->
     if error
       logger.error(error.message) if error.message
-      process.exitCode = 1
       return @_processExit(1)
 
     if (stats.failures + stats.errors) > 0
-      process.exitCode = 1
       @_processExit(1)
     else
       @_processExit(0)