Feature: Configuration Core Module Coverage
  As a developer
  I want to test all edge cases and error conditions in the configuration module
  So that we achieve 90%+ code coverage for config.py

  Background:
    Given the configuration system is initialized for core testing

  Scenario: Configuration file loading with None content
    Given I have a configuration file "empty.yaml" with None content
    When I load the configuration files
    Then the None content should be skipped
    And the configuration should remain empty

  Scenario: Configuration file loading with non-dict content
    Given I have a configuration file "non_dict.yaml" with list content
    When I attempt to load the configuration files
    Then a ConfigurationError should be raised with message about YAML dictionary

  Scenario: Configuration file loading with YAML parsing error
    Given I have a configuration file "invalid_yaml.yaml" with malformed YAML
    When I attempt to load the configuration files
    Then a ConfigurationError should be raised with YAML parsing error

  Scenario: Configuration file loading with file access error
    Given I have a configuration file path that doesn't exist
    When I attempt to load the configuration files
    Then a ConfigurationError should be raised with file loading error

  Scenario: Schema validation with general exception
    Given I have a configuration manager with mocked schema validator
    When the schema validator raises a general exception
    Then a ConfigurationError should be raised with validation failed message

  Scenario: Configuration setting with empty path
    Given I have a configuration manager
    When I attempt to set configuration with empty path
    Then a ConfigurationError should be raised with empty path message

  Scenario: Configuration setting with non-dict parent
    Given I have a configuration manager with nested structure
    When I attempt to set configuration where parent is not a dict
    Then a ConfigurationError should be raised with parent not dictionary message

  Scenario: Configuration setting with non-dict intermediate parent
    Given I have a configuration manager with scalar values
    When I attempt to set configuration with non-dict final parent
    Then a ConfigurationError should be raised with final parent not dictionary message

  Scenario: Environment variable interpolation with missing variable
    Given I have configuration with missing environment variable
    When I perform environment variable interpolation
    Then a ConfigurationError should be raised with environment variable not set message

  Scenario: Environment variable interpolation with default value type conversions
    Given I have configuration with environment variables and default values
    When I perform environment variable interpolation
    Then boolean defaults should be converted to strings
    And integer defaults should remain as strings
    And float defaults should remain as strings
    And string defaults should remain unchanged

  Scenario: String to type conversion with boolean values
    Given I have configuration with string boolean values
    When I perform environment variable interpolation
    Then true strings should be converted to boolean True
    And false strings should be converted to boolean False

  Scenario: String to type conversion with numeric values
    Given I have configuration with string numeric values
    When I perform environment variable interpolation
    Then integer strings should be converted to integers
    And float strings should be converted to floats

  Scenario: Schema validation with agent config not dict
    Given I have configuration with agent config not as dict
    When I validate the configuration for core testing
    Then a ConfigurationError should be raised with agent config must be dictionary message

  Scenario: Schema validation with non-dict agent configuration
    Given I have configuration with non-dict agent entry
    When I validate the configuration for core testing
    Then a ConfigurationError should be raised with agent configuration must be dictionary message

  Scenario: Deep merge with nested dictionaries
    Given I have two configurations with nested dictionary structures
    When I perform deep merge
    Then nested dictionaries should be properly merged
    And values from second config should override first config
    And new keys should be added

  Scenario: Configuration get with various path scenarios
    Given I have a configuration manager with test data
    When I test get method with various paths
    Then empty path should return entire config
    And non-existent paths should return None or default
    And nested paths should return correct values
    And paths with non-dict intermediates should return default

  Scenario: Configuration interpolation with complex nested structures
    Given I have configuration with nested lists and dictionaries
    And environment variables are set for interpolation
    When I perform environment variable interpolation
    Then variables in lists should be interpolated
    And variables in nested dictionaries should be interpolated
    And non-string values should remain unchanged