MLE-26966 Added mock of NuaClient for testing

[rjrudin]

Not testing any connection to Nuclia, but able to test that the model-name and chunk-metadata are handled correctly.

NuaClient is now an interface, DefaultNuaClient is the impl, and MockNuaClient is for testing.

[github-actions]

Copyright Validation Results
Total: 8 | Passed: 8 | Failed: 0 | Skipped: 0 | at: 2026-02-05 19:29:06 UTC | commit: fc54dfc

✅ Valid Files

• marklogic-spark-connector/src/main/java/com/marklogic/spark/core/DocumentPipeline.java
• marklogic-spark-connector/src/main/java/com/marklogic/spark/core/DocumentPipelineFactory.java
• marklogic-spark-connector/src/main/java/com/marklogic/spark/core/nuclia/DefaultNuaClient.java
• marklogic-spark-connector/src/main/java/com/marklogic/spark/core/nuclia/MockNuaClient.java
• marklogic-spark-connector/src/main/java/com/marklogic/spark/core/nuclia/NuaClient.java
• marklogic-spark-connector/src/main/java/com/marklogic/spark/core/nuclia/NucliaDocumentProcessor.java
• marklogic-spark-connector/src/test/java/com/marklogic/spark/core/DocumentPipelineFactoryTest.java
• marklogic-spark-connector/src/test/java/com/marklogic/spark/writer/nuclia/ProcessWithNucliaTest.java

✅ All files have valid copyright headers!

[Copilot]

Pull request overview

This PR introduces a mock implementation of the Nuclia Understanding API (NUA) client to enable testing without making actual API calls. The changes refactor NucliaClient into an interface-based design with DefaultNuaClient as the implementation and MockNuaClient for testing purposes.

Changes:

• Extracted NuaClient interface from the original NucliaClient class
• Renamed NucliaClient to DefaultNuaClient and made it implement NuaClient
• Added MockNuaClient for testing with canned responses
• Updated all references throughout the codebase from NucliaClient to NuaClient/DefaultNuaClient

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
ProcessWithNucliaTest.java	New integration test using MockNuaClient to verify chunk processing and metadata handling
DocumentPipelineFactoryTest.java	Updated test assertions to use renamed getNuaClient() method
NucliaDocumentProcessor.java	Updated to use NuaClient interface instead of concrete class
NuaClient.java	New interface defining the contract for Nuclia API interactions
MockNuaClient.java	New mock implementation returning canned responses for testing
DefaultNuaClient.java	Renamed from NucliaClient, now implements NuaClient interface
DocumentPipelineFactory.java	Updated to instantiate MockNuaClient or DefaultNuaClient based on configuration
DocumentPipeline.java	Updated to use NuaClient interface and simplified resource cleanup

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[Copilot]

Debug print statement should be removed before merging to production code. Use a logger instead if this output is needed for debugging purposes.

Suggested change

System.out.println(doc.getPrettyXml());