Feature: Google Sheets Tracker Authentication
  As a data engineer
  I want to authenticate with Google Sheets API
  So that I can track dataset processing status

  Background:
    Given a temporary credentials directory

  Scenario: Successful authentication with valid credentials
    Given valid service account credentials
    And a valid spreadsheet ID
    When I create a sheets tracker
    Then the tracker should authenticate successfully

  Scenario: Authentication fails with missing credentials file
    Given no credentials file
    And a valid spreadsheet ID
    When I create a sheets tracker
    Then the tracker should fail to authenticate

  Scenario: Authentication fails with invalid credentials
    Given invalid service account credentials
    And a valid spreadsheet ID
    When I create a sheets tracker
    Then the tracker should fail to authenticate

  Scenario: Authentication fails without spreadsheet ID
    Given valid service account credentials
    And no spreadsheet ID
    When I create a sheets tracker
    Then the tracker should be None

  Scenario: Create tracker using environment variables
    Given environment variables are set for sheets
    When I create a sheets tracker using environment variables
    Then the tracker should authenticate successfully

  Scenario: Tracker loads column headers correctly
    Given valid service account credentials
    And a spreadsheet with headers "Dataset Name, Status, Error"
    When I create a sheets tracker
    Then the tracker should identify column "Dataset Name" at index 0
    And the tracker should identify column "Status" at index 1
    And the tracker should identify column "Error" at index 2