[COLLECTIONS-775] CollectionUtilsTest.getFromMap() is flaky

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 4.4
• Fix Version/s: 4.5.0-M1
• Component/s: Collection
• Labels: pull-request-available test
• External issue URL: https://github.com/apache/commons-collections/pull/200
• Assignee: Unassigned
• Reporter: XinT
• Created: 30/Nov/20 17:11
• Updated: 05/Dec/20 15:30
• Resolved: 05/Dec/20 15:30

Description

CollectionUtilsTest.getFromMap() is flaky on line 996: assertEquals(expected, found). We can get the following failure:

[ERROR] CollectionUtilsTest.getFromMap:996 expected:<{oneKey=one, zeroKey=zero}> but was:<{oneKey=one}>

 

The flakiness is introduced by calls to CollectionUtils.get(expected, 0) and CollectionUtils.get(expected, 1). Because CollectionUtils.get() uses a new Java Iterator each time it is called, it's possible that get(0) != get(0) and get(0) = get(1) in two subsequent calls to the "expected" HashMap. The end result is we may have only added {oneKey=one} or {zeroKey=zero}, but not both, to the "found" HashMap.