Add test suite for Bedrock boto_client_config fix (PR#11)

[jsamuel1]

Overview

This PR adds a comprehensive test suite for the critical Bedrock configuration fix implemented in PR #11. The original issue caused AttributeError: 'dict' object has no attribute 'merge' when launching Strands agents with JSON-parsed Bedrock configurations.

Problem Statement

PR #11 fixed the bug where boto_client_config parameters from JSON configuration files were passed as plain dictionaries instead of BotocoreConfig objects, causing runtime errors. However, this critical fix lacked comprehensive test coverage to:

• Verify the fix works correctly in all scenarios
• Prevent future regressions
• Document the expected behavior
• Validate edge cases and error conditions

Solution

This PR adds 20 comprehensive tests organized in 4 logical test classes:

🧪 Test Coverage

1. TestBedrockInstance (10 tests)

• Core functionality: Dict → BotocoreConfig conversion
• Backward compatibility: Existing BotocoreConfig objects unchanged
• Edge cases: None values, empty dictionaries
• Complex scenarios: Real-world configuration validation
• Immutability: Original config objects remain unmodified

2. TestBedrockConfigConversion (4 tests)

• Type validation: BotocoreConfig creation from various dict structures
• Detection logic: isinstance() verification for both dict and BotocoreConfig
• Parameter validation: Various configuration combinations

3. TestBedrockIntegrationScenarios (3 tests)

• JSON parsing simulation: Exact failing scenario from user reports
• Strands launch configs: Typical agent configuration patterns
• Mixed sources: JSON + code configuration combinations

4. TestRegressionPrevention (3 tests)

• Root cause demonstration: Shows the original AttributeError
• Fix verification: Confirms the fix prevents the error
• Attribute validation: Verifies merge() method availability

Key Test Scenarios

✅ Main Fix Verification

# This would have failed before PR #11
config_dict = {"read_timeout": 900, "retries": {"max_attempts": 3}}
result = bedrock.instance(model_id="test", boto_client_config=config_dict)
# Now passes: dict is automatically converted to BotocoreConfig

✅ JSON Configuration Scenario

# Simulates real-world JSON config parsing that was failing
json_config = '{"model_id": "test", "boto_client_config": {"read_timeout": 900}}'
parsed_config = json.loads(json_config)  # Creates dict, not BotocoreConfig
result = bedrock.instance(**parsed_config)  # Now works with PR #11 fix

✅ Error Demonstration

# Shows what was happening before the fix
config_dict = {"read_timeout": 900}
with pytest.raises(AttributeError, match="'dict' object has no attribute 'merge'"):
    config_dict.merge({})  # This was the root cause

Changes Made

Files Added

• tests/test_models_bedrock.py - Complete test suite (590 lines, 20 tests)

Test Quality Features

• ✅ Comprehensive mocking: All BedrockModel calls properly isolated
• ✅ Realistic scenarios: Tests simulate actual user configurations
• ✅ Error demonstration: Shows exactly what would happen without the fix
• ✅ Type safety: Verifies proper isinstance() detection and conversions
• ✅ Immutability: Ensures original configuration objects aren't modified
• ✅ Documentation: Clear test names and comprehensive docstrings

Test Results

$ python -m pytest tests/test_models_bedrock.py -v
============================== test session starts ==============================
collected 20 items

tests/test_models_bedrock.py::TestBedrockInstance::test_instance_with_dict_boto_client_config PASSED [  5%]
tests/test_models_bedrock.py::TestBedrockInstance::test_instance_with_botocore_config_object PASSED [ 10%]
# ... (all 20 tests)
============================== 20 passed in 0.05s ==============================

Benefits

1. 🛡️ Regression Protection: Future changes cannot break this critical functionality
2. 📚 Documentation: Tests serve as living documentation of expected behavior
3. 🔍 Debugging Aid: Clear test failures will pinpoint issues immediately
4. ✅ Confidence: Comprehensive coverage ensures the fix works in all scenarios
5. 🚀 Maintainability: Well-organized tests make future maintenance easier

Relationship to PR #11

This PR directly supports PR #11 by:

• Validating the fix with comprehensive test coverage
• Preventing regressions through automated testing
• Documenting behavior for future developers
• Ensuring reliability for production deployments

Testing Instructions

# Run all new Bedrock tests
python -m pytest tests/test_models_bedrock.py -v

# Run specific test class
python -m pytest tests/test_models_bedrock.py::TestBedrockInstance -v

# Run individual test
python -m pytest tests/test_models_bedrock.py::TestBedrockInstance::test_instance_with_dict_boto_client_config -v

Backwards Compatibility

✅ No breaking changes - This PR only adds tests
✅ No production impact - Tests run in isolation with mocking
✅ Fast execution - All 20 tests complete in 0.05 seconds

---

Closes: Testing gap for PR #11
References: #11 (Bedrock boto_client_config fix)
Type: Test Enhancement
Risk: Low (test-only changes)