Flaky Test: WebDriverManager.getWebDriver() fails with Unable to locate element 'WebSocket Connected'

23:34:16,074  INFO org.apache.zeppelin.WebDriverManager:135 - Exception in WebDriverManager while WebDriverWait 
org.openqa.selenium.TimeoutException: Timed out after 5 seconds waiting for org.apache.zeppelin.WebDriverManager$1@4048362f
Build info: version: '2.48.2', revision: '41bccdd10cf2c0560f637404c2d96164b67d9d67', time: '2015-10-09 13:08:06'
System info: host: 'testing-docker-56b95de6-9c2f-47de-9f0b-7841e060e31d', ip: '172.17.0.9', os.name: 'Linux', os.arch: 'amd64', os.version: '4.8.12-040812-generic', java.version: '1.7.0_76'
Session ID: 9692193b-f9fd-41d5-a4ea-fe6d144487e5
Driver info: org.openqa.selenium.firefox.FirefoxDriver
Capabilities [{platform=LINUX, acceptSslCerts=true, javascriptEnabled=true, cssSelectorsEnabled=true, databaseEnabled=true, browserName=firefox, handlesAlerts=true, nativeEvents=false, webStorageEnabled=true, rotatable=false, locationContextEnabled=true, applicationCacheEnabled=true, takesScreenshot=true, version=31.0}]
	at org.openqa.selenium.support.ui.WebDriverWait.timeoutException(WebDriverWait.java:80)
	at org.openqa.selenium.support.ui.FluentWait.until(FluentWait.java:261)
	at org.apache.zeppelin.WebDriverManager.getWebDriver(WebDriverManager.java:125)
	at org.apache.zeppelin.integration.InterpreterIT.startUp(InterpreterIT.java:45)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:606)
	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
	at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:24)
	at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:27)
	at org.junit.rules.Verifier$1.evaluate(Verifier.java:35)
	at org.junit.rules.RunRules.evaluate(RunRules.java:20)
	at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
	at org.apache.maven.surefire.junit4.JUnit4Provider.execute(JUnit4Provider.java:264)
	at org.apache.maven.surefire.junit4.JUnit4Provider.executeTestSet(JUnit4Provider.java:153)
	at org.apache.maven.surefire.junit4.JUnit4Provider.invoke(JUnit4Provider.java:124)
	at org.apache.maven.surefire.booter.ForkedBooter.invokeProviderInSameClassLoader(ForkedBooter.java:200)
	at org.apache.maven.surefire.booter.ForkedBooter.runSuitesInProcess(ForkedBooter.java:153)
	at org.apache.maven.surefire.booter.ForkedBooter.main(ForkedBooter.java:103)
Caused by: org.openqa.selenium.NoSuchElementException: Unable to locate element: {"method":"xpath","selector":"//i[@tooltip='WebSocket Connected']"}
Command duration or timeout: 45.50 seconds
For documentation on this error, please visit: http://seleniumhq.org/exceptions/no_such_element.html
Build info: version: '2.48.2', revision: '41bccdd10cf2c0560f637404c2d96164b67d9d67', time: '2015-10-09 13:08:06'
System info: host: 'testing-docker-56b95de6-9c2f-47de-9f0b-7841e060e31d', ip: '172.17.0.9', os.name: 'Linux', os.arch: 'amd64', os.version: '4.8.12-040812-generic', java.version: '1.7.0_76'
*** Element info: {Using=xpath, value=//i[@tooltip='WebSocket Connected']}
Session ID: 9692193b-f9fd-41d5-a4ea-fe6d144487e5
Driver info: org.openqa.selenium.firefox.FirefoxDriver
Capabilities [{platform=LINUX, acceptSslCerts=true, javascriptEnabled=true, cssSelectorsEnabled=true, databaseEnabled=true, browserName=firefox, handlesAlerts=true, nativeEvents=false, webStorageEnabled=true, rotatable=false, locationContextEnabled=true, applicationCacheEnabled=true, takesScreenshot=true, version=31.0}]
	at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
	at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.lang.reflect.Constructor.newInstance(Constructor.java:526)
	at org.openqa.selenium.remote.ErrorHandler.createThrowable(ErrorHandler.java:206)
	at org.openqa.selenium.remote.ErrorHandler.throwIfResponseFailed(ErrorHandler.java:158)
	at org.openqa.selenium.remote.RemoteWebDriver.execute(RemoteWebDriver.java:647)
	at org.openqa.selenium.remote.RemoteWebDriver.findElement(RemoteWebDriver.java:353)
	at org.openqa.selenium.remote.RemoteWebDriver.findElementByXPath(RemoteWebDriver.java:490)
	at org.openqa.selenium.By$ByXPath.findElement(By.java:361)
	at org.openqa.selenium.remote.RemoteWebDriver.findElement(RemoteWebDriver.java:345)
	at org.apache.zeppelin.WebDriverManager$1.apply(WebDriverManager.java:128)
	at org.apache.zeppelin.WebDriverManager$1.apply(WebDriverManager.java:125)
	at org.openqa.selenium.support.ui.FluentWait.until(FluentWait.java:238)
	... 28 more
Caused by: org.openqa.selenium.NoSuchElementException: Unable to locate element: {"method":"xpath","selector":"//i[@tooltip='WebSocket Connected']"}
For documentation on this error, please visit: http://seleniumhq.org/exceptions/no_such_element.html