Feature: State Management Missing Coverage
  As a developer
  I want to test specific uncovered code paths in state.py
  So that we achieve complete coverage

  Background:
    Given the state management system is available

  Scenario: GraphState REPLACE mode with non-existent attribute
    Given I have a GraphState instance
    And I have updates with non-existent attributes only
    When I update the state with REPLACE mode for nonexistent attributes
    Then non-existent attributes should be ignored
    And hasattr check should be performed for each attribute

  Scenario: GraphState MERGE mode with non-dict non-list value
    Given I have a GraphState with string metadata
    And I have string updates for merge mode
    When I update the state with MERGE mode for string values
    Then the simple value should replace the existing value
    And line 76 should be executed

  Scenario: GraphState APPEND mode with single item to list
    Given I have a GraphState with list messages
    And I have single item to append to list field
    When I update the state with APPEND mode for string field
    Then the single item should be set as new value
    And line 85 should be executed for non-list field

  Scenario: Direct GraphState from_dict method call
    Given I have a complete state dictionary
    When I call GraphState.from_dict class method directly
    Then a new GraphState instance should be created
    And line 100 should be executed
    And all attributes should be properly set

  Scenario: StateManager history trimming with exact max size
    Given I have a StateManager with time travel enabled
    And I set max history to exactly 2
    When I make exactly 3 state updates
    Then history should be trimmed to 2 entries
    And line 159 should be executed for trimming

  Scenario: StateManager automatic checkpoint saving
    Given I have a StateManager with checkpointing and small interval
    And I set checkpoint interval to 2
    When I make exactly 2 state updates
    Then checkpoint should be saved automatically
    And line 171 should be executed for checkpoint trigger

  Scenario: StateManager with no checkpoint directory
    Given I have a StateManager without checkpoint directory
    When I trigger checkpoint saving
    Then _save_checkpoint should return early
    And lines 177-178 should be executed

  Scenario: StateManager checkpoint loading from file
    Given I have a StateManager with checkpoint directory
    And I have a valid checkpoint file
    When I load checkpoint from the file
    Then state should be restored from checkpoint data
    And lines 195-204 should be executed
    And GraphState.from_dict should be called

  Scenario: StateManager get latest checkpoint from directory
    Given I have a StateManager with checkpoint directory
    And I have checkpoint files in the directory
    When I get the latest checkpoint from directory
    Then the most recent file should be returned
    And lines 208-215 should be executed

  Scenario: StateManager get latest checkpoint with no directory
    Given I have a StateManager without checkpoint directory for latest check
    When I get the latest checkpoint with no directory
    Then None should be returned immediately
    And line 209 should be executed

  Scenario: StateManager time travel with history
    Given I have a StateManager with time travel and history
    And I have made multiple state updates with history
    When I perform time travel operation
    Then state should revert to historical snapshot
    And lines 219-231 should be executed
    And GraphState.from_dict should be called for restoration

  Scenario: StateManager time travel with steps beyond history
    Given I have a StateManager with limited time travel history
    When I try to time travel beyond available history
    Then it should travel to earliest available state
    And steps should be clamped to history length

  Scenario: StateManager get state observable method
    Given I have a StateManager
    When I call get_state_observable method
    Then the behavior subject should be returned
    And line 235 should be executed

  Scenario: StateManager clear history method
    Given I have a StateManager with existing history
    When I call clear_history method
    Then history list should be emptied
    And line 239 should be executed

  Scenario: StateManager reset with no initial state
    Given I have a StateManager with modified state
    When I call reset with no parameters
    Then state should reset to default GraphState
    And lines 243-248 should be executed
    And state stream should emit reset state

  Scenario: StateManager reset with custom initial state
    Given I have a StateManager
    And I have a custom GraphState instance
    When I call reset with the custom initial state
    Then state should be set to the custom instance
    And reset operations should be performed