Centralize the CloudSolrClient mock setup used by CrossDC tests

[epugh]

Description

Found that I missed properly mocking everything when I did the Kafka 3 to 4 migration.

Solution

Centralize the CloudSolrClient mock setup used by these tests. SolrMessageProcessor reads live nodes from the client’s ClusterStateProvider; the shared helper configures that dependency consistently.

Tests

Reran the tests.

Checklist

[dsmiley]

ai generated

this module already has integration tests over the same code path — SimpleSolrIntegrationTest, ZkConfigIntegrationTest, SolrAndKafkaReindexTest — running against a real MiniSolrCloudCluster. They passed throughout. The mock-based tests are the ones that wedged CI, and they're the ones that had to be hand-edited to keep compiling.

(end)

Makes me question if this module needs mocks in the first place. I hate mocks. But I didn't look with my own eyes closely.

[epugh]

ai generated

this module already has integration tests over the same code path — SimpleSolrIntegrationTest, ZkConfigIntegrationTest, SolrAndKafkaReindexTest — running against a real MiniSolrCloudCluster. They passed throughout. The mock-based tests are the ones that wedged CI, and they're the ones that had to be hand-edited to keep compiling.

(end)

Makes me question if this module needs mocks in the first place. I hate mocks. But I didn't look with my own eyes closely.

I share your sentiment on the Mocks.

Many of the tests in this module don't use mocks... I specifically asked about eliminating the all together, and the only reaosn I went with mocks was that when I aske claude about "hey, how do I tickle this specific data scenario with real embedded solr etc" it said it would jump up the test time!

I didn't actually try to do that and verify that the test duration would increase.. I'd be open to givign that a stab and just seeing....?

[epugh]

@sigram can you give this a review? I'd like oto merge it in hte next day or so to get it off my WIP queue!

[sigram]

LGTM.