Trying to reproduce https://github.com/rails/rails/issues/9015

gistfile1.rb

require 'bundler'
Bundler.setup(:default)

require 'pg'
require_relative 'lib/active_record'
require 'minitest/autorun'
require 'logger'

require 'byebug'

ActiveRecord::Base.establish_connection(adapter: 'postgresql', database: 'test123')
ActiveRecord::Base.logger = Logger.new(STDOUT)

ActiveRecord::Schema.define do
  create_table :some_table, force: true do |t|
  end
  create_table :my_prefix_some_table, force: true do |t|
  end
end

ActiveRecord::SchemaDumper.ignore_tables = ["some_table"]

class BugTest < Minitest::Test
  def test_schema_dumper
    conn = ActiveRecord::Base.connection

    stream = StringIO.new
    ActiveRecord::SchemaDumper.dump(conn, stream)

    assert_match %r{create_table "my_prefix_some_table"}, stream.string
    refute_match %r{create_table "some_table"}, stream.string
  end
end