Browser disconnected error. This problem may appear when a browser hangs or is closed, or due to network issues

[SynaQE]

Hi Testcafe team,

I run my tests nightly using Bamboo CI server and the daily test runs are failing because of the following issue:

Using locally installed version of TestCafe.
ERROR The Safari 10.1.1 / Mac OS X 10.12.5 browser disconnected. This problem may appear when a browser hangs or is closed, or due to network issues.

I use testcafe 'all' command (e.g testcafe all abc.js) to run scripts on Safari,Firefox & Chrome on Mac machine. Version of each provided below:

TestCafe ver: 0.16.2
Mac OS: 10.12.5
Safari ver: 10.1.1
Chrome ver: 50.0.3071
Firefox ver: 54.0.1

What could be the problem here and why does the browser hang?

[churkin]

Hi,

Unfortunately, I can't find a solution using the information that you provided. The error says that testcafe lost connection with one of the browsers. First, I suggest you try to find the problematic browser - run tests differently in each of them. After this, watch for the behavior of the problematic browser - it should open, should run tests, and should not hang on testing.

Let me know your results.

[SynaQE]

Hi @churkin

I investigated and as far as I can tell, the issue occurs when running along with Firefox browser. Another user has reported the similar issue here

Here are my results:

FAIL - when run with 'safari, chrome,firefox' browsers multiple times (Note: First run from clean state is always fine. Subsequent runs fail because Safari browser froze while running the tests)
PASS - when run with just 'safari' multiple times
PASS - when run with just 'chrome' multiple times
PASS - when run with just 'firefox' multiple times
PASS - when run with 'safari,chrome' multiple times

Could Firefox browser be doing something to cause this issue?

[churkin]

Hi,
Thank you for the additional information about the problem. I will investigate it and let you know as soon as we have any results.

[moffsugita]

ERROR The Firefox 59.0.0 / Mac OS X 10.13.0 browser disconnected. This problem may appear when a browser hangs or is closed, or due to network issues.

memory shortage?
It happened when MacBook Pro is working with noisy fan.

[SynaQE]

Same here. I'm getting the same problem with Safari. Note: I have not had any issues with Chrome.

We are running around 200+ TestCafe test scripts on daily basis (nightly run). On Safari, test runs are failing because of following issue:

ERROR The Safari 11.1.0 / Mac OS X 10.12.6 browser disconnected. This problem may appear when a browser hangs or is closed, or due to network issues.

Here how I run tests. I launch the app using TestCafe to run the tests:
testcafe safari calendar.js compose.js contacts.js mail.js notes.js search.js settings.js tasks.js -e --app 'npm run serve' --app-init-delay 5000 -r html-testrail,xunit:result.xml

We are using Mac Pro server with 32 GB RAM and using latest TestCafe v0.20.0-alpha.1.

@churkin or someone else from TestCafe team investigate?

[MarinaRukavitsyna]

Hello guys,
We could not find the cause of the problem. Would you please provide us with a failed test and a link to the problematic page so that we can see the issue locally? If you do not want to share your web site with other users, you may send a private message to me.

[SynaQE]

@MarinaRukavitsyna - I installed TestCafe Debug build 0.17.3-git201709131433, executed our 200+ testscripts in Safari and ran into the same browser disconnected error. Attached 'testcafe-browser-tools.log' & 'find-window.log'. I see execution error: File permission error. in the logs. Does that give any clue as to why the browser got disconnected?

Is there a way I can make the TestCafe debug build to print out the exact failed test-case name in the log file by enabling a flag? If so, then I can easily provide you the exact failed test and the link to problematic page.

find-window.log (557 Bytes)
testcafe-browser-tools.log (1.6 KB)

P.S - I monitored my test runs and I see that the TestCafe failure is happening at random intervals. Its not consistently failing at 1 particular test. . I think we need this feature in soon - https://github.com/DevExpress/testcafe/issues/1815

[moffsugita]

Chrome and Safari is okey.
it is bug for Edge, Firefox.
do you use Role?

Issue: Script error in Firefox/IE/Edge when using a Role

beforeEach waiting is needed?

    .beforeEach(async t => {
    	await t.expect(Selector('input[type="text"]').exists).ok({ timeout: 10000 });
    });

[moffsugita]

I have 32 testcase files.
test file No7 is starting file always happened.
However, if I run only test file No7 is success.

[moffsugita]

Issue: Browser disconnected. This problem may appear when a browser hangs or is closed, or due to network issues.

perhaps, use 127.0.0.1 is good choice?

however I don't use browserstack...

but, it was not resolve.

I ran testcafe-live, I passed No7 test case,
TestCafe randomly run. I can't understand.

I hope forcely re-connect option

[moffsugita]

Firefox Local Test Execution Fails

same post

[moffsugita]

Testcafe-live does not disconnected error.
Just replace command testcafe to testcafe-live is good practice?

FYI
https://www.npmjs.com/package/testcafe-live

[AndreyBelym]

Hello @moffsugita, @SynaQE!

Unfortunately, it's very hard to diagnose what causes the problem. This error appears when a browser doesn't respond to TestCafe server for 2 minutes. In most cases it means that browser has crashed or hung completely. We can't do much without access to your test page and test code. Maybe video recording of the browser will give some clues.

@moffsugita, what version of standalone TestCafe do you use? If you tried the 0.20.0-alpha1, it might be a regression, because TestCafe Live uses the latest stable version (0.19.2) under the hood.

[SynaQE]

@AndreyBelym / @MarinaRukavitsyna / @churkin - I sent a private message with details on how to access & run our test suite to reproduce this issue.

[moffsugita]

what version of standalone TestCafe do you use?

I use version 0.19.1.

[MarinaRukavitsyna]

Please try to update your version to v19.2.

[moffsugita]

however it happened.
new version 0.20.0

 Getting Started

Stopping TestCafe Live...
events.js:167
      throw er; // Unhandled 'error' event
      ^

Error: read ECONNRESET
    at TCP.onread (net.js:659:25)
Emitted 'error' event at:
    at Socket.onerror (_stream_readable.js:696:12)
    at Socket.emit (events.js:182:13)
    at Socket.EventEmitter.emit (domain.js:442:20)
    at emitErrorNT (internal/streams/destroy.js:92:8)
    at emitErrorAndCloseNT (internal/streams/destroy.js:59:3)
    at process._tickCallback (internal/process/next_tick.js:174:19)

[MarinaRukavitsyna]

@moffsugita
In this case, please provide us with access to your web site so that we can check and debug the issue locally.

[moffsugita]

I can't provide web site
but it is error of browser.

Failed to load resource: net::ERR_CONNECTION_REFUSED
task.js:1 Failed to load resource: net::ERR_CONNECTION_REFUSED
hammerhead.js:3 Uncaught TypeError: Cannot read property 'body' of undefined
    at t.initDocumentBodyListening (hammerhead.js:3)
    at t._onBodyCreated (hammerhead.js:6)
    at admin.html:22
    at admin.html:22
testcafe-ui-styles.css:1 GET http://192.168.1.47:49753/testcafe-ui-styles.css 0 ()