feat: add comprehensive unit tests for bittensor.core.settings module

[codomposer]

Add Comprehensive Unit Tests for Core Settings Module

Description of the Change

This PR adds comprehensive unit test coverage for the bittensor/core/settings.py module, which is a critical infrastructure component used throughout the entire Bittensor codebase.

The test suite includes 30 tests organized into logical test classes covering:

• Network Configuration: Validates NETWORKS list, NETWORK_MAP, REVERSE_NETWORK_MAP, and bidirectional mapping consistency
• Environment Variables: Tests READ_ONLY mode, LOCAL_ENTRYPOINT overrides, and environment variable handling
• Directory Configuration: Verifies WALLETS_DIR and MINERS_DIR path construction and creation logic
• Version Handling: Tests version parsing (X.Y.Z format) and version_as_int conversion
• Constants: Validates SS58_FORMAT, BLOCKTIME, currency symbols (TAO/RAO), SS58_ADDRESS_LENGTH, DEFAULT_PERIOD, and ROOT_TAO_STAKE_WEIGHT
• Type Registry: Verifies Balance type override (u64 not u128)
• DEFAULTS Configuration: Comprehensive testing of all default configurations for axon, logging, priority threadpool, subtensor, and wallet
• Endpoint Constants: Tests all network endpoint URLs (FINNEY, FINNEY_TEST, ARCHIVE, LATENT_LITE)
• Miscellaneous: Validates PIPADDRESS and TAO_APP_BLOCK_EXPLORER constants

Test Coverage: Achieves 100% code coverage of the settings module.

Alternate Designs

Alternative approaches considered:

• Single monolithic test file: Rejected in favor of organized test classes for better maintainability
• Integration tests only: Rejected because settings are foundational and require unit-level validation
• Partial coverage: Rejected because settings errors would be catastrophic throughout the codebase

The chosen design uses pytest best practices with:

• Clear class-based organization by functionality
• Descriptive test names following test_<what_is_tested>() convention
• Proper mocking for environment variable tests to avoid side effects
• Comprehensive assertions validating both values and types

Possible Drawbacks

• Minimal drawbacks: This is purely additive test coverage with no changes to production code
• Test maintenance: Tests will need updates if settings constants change, but this is expected and beneficial
• Test execution time: Adds ~0.2 seconds to test suite runtime (negligible)

Verification Process

Test Execution

python -m pytest tests/unit_tests/test_settings.py -v

Result: All 30 tests passed ✅

Coverage Verification

python -m pytest tests/unit_tests/test_settings.py -v --cov=bittensor.core.settings --cov-report=term-missing

Result: 100% code coverage achieved ✅

Tests Validated

• ✅ Network constants and mappings are correct
• ✅ Environment variable overrides work properly
• ✅ Directory paths are constructed correctly
• ✅ Version parsing and conversion logic is accurate
• ✅ All constants have expected values
• ✅ Type registry overrides are correct
• ✅ DEFAULTS configuration structure is complete
• ✅ All endpoint URLs are valid

Contribution by Gittensor, learn more at https://gittensor.io/

[codomposer]

@basfroman Could you please take a look this PR?

[thewhaleking]

I'm at a loss here.

[codomposer]

I'm at a loss here.

I am sorry, let me remove unnecessary test use cases