Summary

This PR adds extensive test coverage for OllamaChatModel and OllamaEmbeddingModel to improve robustness and catch edge cases.

Changes Made

OllamaChatModel Tests

• Builder validation: Tests for null API validation and complete builder options
• Metadata handling: Edge cases with zero, large, and null values
• Aggregation scenarios: Complex metadata aggregation and overflow handling
• Model configuration: Parameterized tests for different OllamaModel types
• Data preservation: Model name and timestamp handling in metadata
• Immutability: Verification that builder creates distinct instances

OllamaEmbedding Tests

• Input handling: Empty inputs, multiple inputs, and input order preservation
• Options override: Runtime options properly overriding defaults
• Keep-alive formats: Different duration formats (seconds, hours, etc.)
• Minimal configuration: Tests with bare minimum settings
• Whitespace handling: Preservation of whitespace-only and empty inputs

Test Coverage Improvements

• Edge case handling for boundary values and null inputs
• Robust validation of configuration options and their precedence
• Data integrity verification for metadata aggregation
• Comprehensive input format testing

Quality Assurance

• All tests follow existing patterns using AssertJ assertions
• Maintains consistency with current test structure
• Uses appropriate mocking with Mockito where needed
• Includes parameterized tests for efficiency

These tests help ensure the Ollama integration handles various real-world scenarios correctly and maintains backward compatibility.