Generate consumer group in KafkaSourceUpdate test (#1158)
Generate consumer group in KafkaSourceUpdate test (#1158)

Using the same consumer group for the different sources might produce
unreliable results because Kafka group ids are shared.

This is particularly evident in eventing-kafka-broker where the same
tests (`KafkaSourceUpdate`) is executed 5 times [1] in parallel [2]
(to catch flakes early), which means that there might be different
sources with the same consumer group pointing to 2 different sinks.

[1] https://github.com/knative-sandbox/eventing-kafka-broker/blob/e169e2cb923890a23e8d65651876292283b63908/test/e2e/kafka_source_test.go#L31
[2] https://github.com/knative-sandbox/eventing-kafka-broker/blob/e169e2cb923890a23e8d65651876292283b63908/test/pkg/testing/run.go#L52-L67

Signed-off-by: Pierangelo Di Pilato <f5f1d2015efd0bb51da99f56609dc938930158a7@redhat.com>
knative-sandbox/eventing-kafka,knative-sandbox/eventing-kafka