Feature: /switch command — activate a different session

  Background:
    Given user "user_abc123" is sending commands

  Scenario: No sessions returns error
    When user sends "/switch 1"
    Then reply contains "No sessions available"

  Scenario: Valid switch updates active session
    Given user has session "sess01" in "/tmp/proj1"
    And user has session "sess02" in "/tmp/proj2"
    When user sends "/switch 2"
    Then reply contains "Switched to session"
    And active session for user "user_abc123" is "sess02"

  Scenario: Out of range number returns error
    Given user has session "sess01" in "/tmp/proj1"
    When user sends "/switch 5"
    Then reply contains "Invalid session number"

  Scenario: Non-numeric argument returns error
    Given user has session "sess01" in "/tmp/proj1"
    When user sends "/switch notanumber"
    Then reply contains "Invalid number"

  Scenario: Missing argument shows usage
    Given user has session "sess01" in "/tmp/proj1"
    When user sends "/switch"
    Then reply contains "Usage: /switch"