[MAPREDUCE-1128] MRUnit Allows Iteration Twice

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 0.20.1
• Fix Version/s: 0.21.0
• Component/s: contrib/mrunit

Environment

Java 1.6, Hadoop 0.21.1+133 (cloudera distribution for hadoop)

• Hadoop Flags: Reviewed
• Assignee: Aaron Kimball
• Reporter: Ed Kohlwey
• Created: 21/Oct/09 12:54
• Updated: 24/Aug/10 21:18
• Resolved: 05/Nov/09 06:01

Description

MRUnit allows one to iterate over a collection of values twice (ie.

reduce(Key key, Iterable<Value> values, Context context){
for(Value : values ) /* iterate once */;
for(Value : values ) /* iterate again */;
}

Hadoop will allow this as well, however the second iterator will be empty. MRUnit should either match hadoop's behavior or warn the user that their code is likely flawed.