[HBASE-7384] Introducing waitForCondition function into test cases

• Type: Test
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 0.95.0
• Component/s: test
• Labels: test
• Hadoop Flags: Reviewed
• Assignee: Jeffrey Zhong
• Reporter: Jeffrey Zhong
• Created: 18/Dec/12 23:44
• Updated: 23/Sep/13 18:30
• Resolved: 12/Jan/13 02:07

Description

Recently I'm working on flaky test cases and found we have many places using while loop and sleep to wait for a condition to be true. There are several issues in existing ways:

1) Many similar code doing the same thing
2) When time out happens, different errors are reported without explicitly indicating a time out situation
3) When we want to increase the max timeout value to verify if a test case fails due to a not-enough time out value, we have to recompile & redeploy code

I propose to create a waitForCondition function as a test utility function like the following:

    public interface WaitCheck {
        public boolean Check() ;
    }

    public boolean waitForCondition(int timeOutInMilliSeconds, int checkIntervalInMilliSeconds, WaitCheck s)
            throws InterruptedException {

        int multiplier = 1;
        String multiplierProp = System.getProperty("extremeWaitMultiplier");
        if(multiplierProp != null) {
            multiplier = Integer.parseInt(multiplierProp);
            if(multiplier < 1) {
                LOG.warn(String.format("Invalid extremeWaitMultiplier property value:%s. is ignored.", multiplierProp));
                multiplier = 1;
            }
        }

        int timeElapsed = 0;
        while(timeElapsed < timeOutInMilliSeconds * multiplier) {
            if(s.Check()) {
                return true;
            }
            Thread.sleep(checkIntervalInMilliSeconds);
            timeElapsed += checkIntervalInMilliSeconds;
        }
        assertTrue("WaitForCondition failed due to time out(" + timeOutInMilliSeconds + " milliseconds expired)",
                false);

        return false;
    }

By doing the above way, there are several advantages:

1) Clearly report time out error when such situation happens
2) Use System property extremeWaitMultiplier to increase max time out dynamically for a quick verification
3) Standardize current wait situations

Pleas let me know what your thoughts on this.

Thanks,
-Jeffrey