Feature: cannot make the main branch a contribution branch

  Background:
    Given an uncommitted file
    When I run "git-town contribute"

  Scenario: result
    Then it runs no commands
    And it prints the error:
      """
      cannot make the main branch a contribution branch
      """
    And the current branch is still "main"
    And the main branch is still "main"
    And the uncommitted file still exists
    And there are still no contribution branches

  Scenario: undo
    When I run "git-town undo"
    Then it runs no commands
    And the current branch is still "main"
    And the main branch is still "main"
    And there are still no contribution branches
