BIND 10 #2973: write tests for ZoneWriter::install

[BIND 10 Development]

#2973: write tests for ZoneWriter::install
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            Reporter:  jinmei        |                        Owner:
                Type:  defect        |  jinmei
            Priority:  medium        |                       Status:
           Component:  data source   |  reviewing
            Keywords:                |                    Milestone:
           Sensitive:  0             |  Sprint-20130625
         Sub-Project:  DNS           |                   Resolution:
Estimated Difficulty:  4             |                 CVSS Scoring:
         Total Hours:  0             |              Defect Severity:  N/A
                                     |  Feature Depending on Ticket:
                                     |          Add Hours to Ticket:  0
                                     |                    Internal?:  0
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Comment (by jinmei):

 Thanks for the review.

 Replying to [comment:8 vorner]:

 > The code looks good. However, the semantics of the `addZone` method
 chandeg (the caller is now responsible to free it). But I don't see any
 other place updated in such manner. Is it that it was already freed
 (twice) before?

 zone_table_unittest in a169232953e34690749708a29b9f6c22e94b2dbf was
 updated according to the semantics change, although it may not look so
 straightforward.

 The main `ZoneWriter` class has already freed it on exception other
 than `MemorySegmentGrown` thanks to the holder object.  But it's quite
 difficult to trigger an exception (other than `MemorySegmentGrown`)
 from `ZoneWriter`, so it's not been tested.

-- 
Ticket URL: <http://bind10.isc.org/ticket/2973#comment:9>
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