Adding ProducerRecord to ConsumerRecord mapper to MockKafka builder

[sivanmz]

The current implementation discards the record headers. The constructors for ConsumerRecord have some arguments that don't make sense for mocking, but I do need the headers.

I thought it would be good to parameterize the mapping from ProducerRecord to ConsumerRecord, with the default being the current implementation.

(I'm not that experienced with Git and pull requests and had to clean up some accidental reformatting)

Example usage:

    _kafkaFactory = new MockKafka<String, byte[]>()
            .withRecordMapper((inProducerRecord, inRecordMetadata) -> {
                int partition = inProducerRecord.partition() != null ? inProducerRecord.partition() : inRecordMetadata.partition();
                return new ConsumerRecord<String, byte[]>(inProducerRecord.topic(), partition, inRecordMetadata.offset(),
                        inRecordMetadata.timestamp(),
                        TimestampType.NO_TIMESTAMP_TYPE, -1L, -1, -1, inProducerRecord.key(),
                        inProducerRecord.value(), inProducerRecord.headers());
            });

[codecov-io]

Codecov Report

Merging #2 into master will not change coverage.
The diff coverage is 100%.

@@           Coverage Diff           @@
##             master     #2   +/-   ##
=======================================
  Coverage       100%   100%           
- Complexity      256    259    +3     
=======================================
  Files            42     42           
  Lines           724    730    +6     
  Branches         47     47           
=======================================
+ Hits            724    730    +6

Impacted Files	Coverage Δ	Complexity Δ
...n/java/com/obsidiandynamics/jackdaw/MockKafka.java	100% <100%> (ø)	32 <8> (+3)	⬆️

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[ekoutanov]

Would you mind fixing the coverage issue? I would like to run it at 100% branch coverage please.

Also, I'd happily have us change the default mapper implementation to push the headers through. Makes sense to do it.

[sivanmz]

Added test. Something is reformatting my commits, I can try to fix if you prefer. Sorry.

[ekoutanov]

Nah that's ok. What do you think of making header passing as part of the default mapper?

[sivanmz]

Agree that headers should be passed by default.

[ekoutanov]

If you'd like to make that change, I'll pull it all in one go.

[sivanmz]

Done