The tests were failing with "grpc: Server.RegisterService after
Server.Serve" because setupMockServer() was starting the gRPC server
before tests could register their services. gRPC requires all services
to be registered before Server.Serve() is called.
Changes:
- Remove s.Serve() from setupMockServer() helper function
- Add s.Serve() to each test after service registration
- Apply fix consistently to all 6 affected tests:
* TestZillizClient_Embedding
* TestZillizClient_Embedding_Error
* TestZillizClient_Rerank
* TestZillizClient_Rerank_Error
* TestNewZilliClient_WithMockServer
* TestZillizClient_Embedding_EmptyResponse
This follows the correct gRPC server lifecycle:
1. Create server
2. Register services
3. Start serving
Related to #44620
Case: "internal/util/function/models/zilliz TestZillizClient_Rerank"
Signed-off-by: Congqi Xia <congqi.xia@zilliz.com>