fix(test): guard from repeated executions of the karma run

'data' event handler may be called multiple times, which will result in
multiple calls to karma run. To take it even further its execution is
delayed by setTimeout, which means that subsequent executions will run
while next test scenario is in progress and may mess it up. To prevent
this make sure that karma run is executed only once independently of how
many time 'data' event is fired.

test/e2e/step_definitions/core_steps.js

@@ -65,6 +65,7 @@ cucumber.defineSupportCode((a) => {
 
         const runOut = command === 'runOut'
         if (command === 'run' || command === 'runOut') {
+          let isRun = false
           this.child = spawn('' + runtimePath, ['start', '--log-level', 'warn', configFile])
           const done = () => {
             cleansingNeeded = true
@@ -84,20 +85,24 @@ cucumber.defineSupportCode((a) => {
           this.child.stdout.on('data', (chunk) => {
             this.lastRun.stdout += chunk.toString()
             const cmd = runtimePath + ' run ' + configFile + ' ' + additionalArgs
-            setTimeout(() => {
-              exec(cmd, {
-                cwd: baseDir
-              }, (error, stdout, stderr) => {
-                if (error) {
-                  this.lastRun.error = error
-                }
-                if (runOut) {
-                  this.lastRun.stdout = stdout
-                  this.lastRun.stderr = stderr
-                }
-                done()
-              })
-            }, 1000)
+            if (!isRun) {
+              isRun = true
+
+              setTimeout(() => {
+                exec(cmd, {
+                  cwd: baseDir
+                }, (error, stdout, stderr) => {
+                  if (error) {
+                    this.lastRun.error = error
+                  }
+                  if (runOut) {
+                    this.lastRun.stdout = stdout
+                    this.lastRun.stderr = stderr
+                  }
+                  done()
+                })
+              }, 1000)
+            }
           })
         } else {
           executor((error, stdout, stderr) => {
@@ -130,8 +135,8 @@ cucumber.defineSupportCode((a) => {
     setTimeout(function () {
       stopper.stop(_this.configFile, function (exitCode) {
         _this.stopperExitCode = exitCode
+        callback()
       })
-      callback()
     }, 1000)
   })
 

test/e2e/stop.feature

@@ -44,7 +44,7 @@ Feature: Stop karma
     """
 
 
-  Scenario: A server can be stopped programically
+  Scenario: A server can be stopped programmatically
     Given a configuration with:
       """
       files = ['basic/plus.js', 'basic/test.js'];