[FINE] No subscribers registered for event class com.kms.katalon.core.event.TestingEvent

Please let us know what you are using Katalon Studio for?

  1. I have currently applied Katalon Studio in my project

How would your work be affected if this issue has not been resolved?

  1. It doesn’t affect much, but I believe Katalon team should have this ticket resolved

Operating System

  • macOS 11 Big Sur

Katalon Studio Version


Katalon Studio logs

  • macOS logs folder: file:///Applications/Katalon%20Studio.app/Contents/MacOS/config/.metadata/.plugins/org.eclipse.ui.workbench/log

katalon.log (2.8 KB)

Screenshots / Videos

how to reproduce

I made a simple Test Case:

import com.kms.katalon.core.webui.keyword.WebUiBuiltInKeywords as WebUI


When I ran it, i got the following output in the console

2021-03-04 09:52:31.771 INFO  c.k.katalon.core.main.TestCaseExecutor   - --------------------
2021-03-04 09:52:31.777 INFO  c.k.katalon.core.main.TestCaseExecutor   - START Test Cases/simplest
2021-03-04 09:52:33.273 DEBUG testcase.simplest                        - 1: openBrowser("")
2021-03-04 09:52:33.729 INFO  c.k.k.core.webui.driver.DriverFactory    - Starting 'Chrome' driver
3 04, 2021 9:52:33 午前 org.openqa.selenium.remote.DesiredCapabilities chrome
情報: Using `new ChromeOptions()` is preferred to `DesiredCapabilities.chrome()`
2021-03-04 09:52:33.828 INFO  c.k.k.core.webui.driver.DriverFactory    - Action delay is set to 0 milliseconds
Starting ChromeDriver 88.0.4324.96 (68dba2d8a0b149a1d3afac56fa74648032bcf46b-refs/branch-heads/4324@{#1784}) on port 17271
Only local connections are allowed.
Please see https://chromedriver.chromium.org/security-considerations for suggestions on keeping ChromeDriver safe.
ChromeDriver was started successfully.
3 04, 2021 9:52:36 午前 org.openqa.selenium.remote.ProtocolHandshake createSession
情報: Detected dialect: W3C
2021-03-04 09:52:36.927 INFO  c.k.k.core.webui.driver.DriverFactory    - sessionId = be9d157823a35da4e242594c602daa33
2021-03-04 09:52:36.958 INFO  c.k.k.core.webui.driver.DriverFactory    - browser = Chrome 88.0.4324.192
2021-03-04 09:52:36.959 INFO  c.k.k.core.webui.driver.DriverFactory    - platform = Mac OS X
2021-03-04 09:52:36.959 INFO  c.k.k.core.webui.driver.DriverFactory    - seleniumVersion = 3.141.59
2021-03-04 09:52:36.961 INFO  c.k.k.core.webui.driver.DriverFactory    - proxyInformation = ProxyInformation { proxyOption=NO_PROXY, proxyServerType=HTTP, username=, password=********, proxyServerAddress=, proxyServerPort=0, executionList="", isApplyToDesiredCapabilities=true }
[FINE] No subscribers registered for event class com.kms.katalon.core.event.TestingEvent
[FINE] No subscribers registered for event class org.greenrobot.eventbus.NoSubscriberEvent
2021-03-04 09:52:37.011 DEBUG testcase.simplest                        - 2: navigateToUrl("http://demoaut.katalon.com/")
2021-03-04 09:52:39.808 DEBUG testcase.simplest                        - 3: waitForPageLoad(10)
2021-03-04 09:52:40.070 DEBUG testcase.simplest                        - 4: delay(3)
2021-03-04 09:52:43.109 DEBUG testcase.simplest                        - 5: closeBrowser()
2021-03-04 09:52:43.273 INFO  c.k.katalon.core.main.TestCaseExecutor   - END Test Cases/simplest

Please note the following 2 lines:

[FINE] No subscribers registered for event class com.kms.katalon.core.event.TestingEvent
[FINE] No subscribers registered for event class org.greenrobot.eventbus.NoSubscriberEvent

These 2 lines are annoying.


My study

  1. I found a similar issue in the Stackoverflow: android - GreenRobot EventBus error : No subscribers registered for event - Stack Overflow
  2. I think that these messages are emitted by greenrobot/EventBus
  3. com.kms.katalon.core.event.TestingEvent contains com.kms.katalon.core.event.TestingEventType
  4. TestingEventType has only 1 instance: BROWSER_OPENED
  5. I searched for any class that implement onTestingEvent() menthod. I found only one.com.kms.katalon.core.context.internal.VideoRecorderService
  6. I guess, this incident has something to do with the feature of Katalon Studio to take video of Test Suite. Possibly video is expected to start when a browser is started. Katalon Studio used the pub-sub architecture of greenrobot/EventBus to let the Test Case and VideoRecorderService to communicate, while keeping them loothly-coupled. But unfortunately possibly something is broken.
1 Like

Hi @kazurayam,

Yup, you’re right about how it works and what the incident be.

I’m sorry for my mistake that’s annoying you /=)

I have tried to disable those messages by changing the log level or disable them directly in the EvenBus instance but got no luck.

The only workaround for now that I’ve found is to create a dummy subscriber and subscribe to that event.

Thanks for taking your time to investigate and describe the issue in detail. We’ll plan to fix this soon. And below is the snippet for my workaround. You can add it to the BeforeTestCase listener to affect all runs.

import org.greenrobot.eventbus.EventBus
import org.greenrobot.eventbus.Subscribe

import com.kms.katalon.core.event.EventBusSingleton
import com.kms.katalon.core.event.TestingEvent

class NewTestListener {

	class DummySubscriber {
		public void onTestingEvent(TestingEvent event) { }

	def sampleBeforeTestCase(TestCaseContext testCaseContext) {
		EventBus eventBus = EventBusSingleton.getInstance().getEventBus()
		eventBus.register(new DummySubscriber())

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