I've created a custom test file only with the two problematic test cases. Without column reset it fails with the error below. As far as I can tell the first test case doesn't do anything destructive. Any idea?

gistfile1.rb

require "cases/helper"
require 'models/default'
require 'models/entrant'

class CustomTest < ActiveRecord::TestCase

  # FROM defaults_test.rb
  def test_default_integers
    default = Default.new
    assert_instance_of Fixnum, default.positive_integer
    assert_equal 1, default.positive_integer
    assert_instance_of Fixnum, default.negative_integer
    assert_equal(-1, default.negative_integer)
    assert_instance_of BigDecimal, default.decimal_number
    assert_equal BigDecimal.new("2.78"), default.decimal_number

    # Fix?
    # Default.reset_column_information
  end

  # FROM cases/base_test.rb test_default method
  def test_xdefault                                                                                      
    with_timezone_config default: :local do                                                             
      default = Default.new                                                                             

      # fixed dates / times                                                                             
      assert_equal Date.new(2004, 1, 1), default.fixed_date                                             
      assert_equal Time.local(2004, 1,1,0,0,0,0), default.fixed_time                                    

      # char types                                                                                      
      assert_equal 'Y', default.char1                                                                   
      assert_equal 'a varchar field', default.char2                                                     
      assert_equal 'a text field', default.char3                                                        
    end
  end
end

gistfile2.txt

CustomTest#test_xdefault [test/cases/custom.rb:28]:
Expected: 2004-01-01 00:00:00 +0100
  Actual: 2004-01-01 00:00:00 UTC