assert csv file

assert_csv.rb

module AssertCSV
  def assert_csv(expected_csv_path, options={}, &block)
    ignore = options[:ignore] || []
    actual_csv_string = CSV.generate { |actual_csv| yield actual_csv }
    actual_rows = CSV.parse(actual_csv_string)
    expected_rows = CSV.read(expected_csv_path)
    if ENV['STORE_ACTUAL_CSV'] && actual_rows != expected_rows
      CSV.open("#{expected_csv_path}.actual", "wb") {|csv| actual_rows.each {|row| csv << row}}
    end
    assert_equal expected_rows.size, actual_rows.size
    actual_header = actual_rows.first
    expected_header = expected_rows.first
    errors = []
    if actual_header != expected_header
      missing = expected_header - actual_header
      errors << "Missing columns: #{missing.inspect}" unless missing.empty?
      unexpected = actual_header - expected_header
      errors << "Unexpected columns: #{unexpected.inspect}" unless unexpected.empty?
    end
    common_header = actual_header & expected_header
    (1...actual_rows.size).each do |i|
      if actual_rows[i] != expected_rows[i]
        row_errors = []
        actual_header.each_with_index do |column, actual_i|
          next if ignore.include?(column)
          if expected_i = expected_header.index(column)
            if actual_rows[i][actual_i] != expected_rows[i][expected_i]
              row_errors << "  #{column} actual=#{actual_rows[i][actual_i]} expected=#{expected_rows[i][expected_i]}"
            end
          end
        end
        unless row_errors.empty?
          errors << "The following mismatches were found in line #{i+1}:"
          errors += row_errors
        end
      end
    end
    assert errors.empty?, errors.join("\n")
  end
end