minitest - 无法在 miniTest 中使用 before_suite 方法创建实例变量

Question

我想在所有测试用例之前创建一个@conn并且可以用于所有测试用例，所以我做了类似的事情：

class SQLTest < Test::Unit::TestCase
    def self.before_suite                                                       
        @conn = PG.connect(dbname:'MapSwitcher',host:'localhost', user:'Lin')
    end
    def  test_employee_table_have_5_entries
        result = @conn.exec("SELECT COUNT(*) FROM employees")
        assert_equal(result.getvalue(0,0).to_i, 5)
     end

end

我得到一个错误：

noMethodError: private method `exec' called for nil:NilClass

似乎@conn在测试用例中无法访问，

Answer 1

class SQLTest < MiniTest::Unit::TestCase
  def setup
    @conn = PG.connect(dbname:'MapSwitcher',host:'localhost', user:'Lin')
  end

  def test_employee_table_have_5_entries
    result = @conn.exec("SELECT COUNT(*) FROM employees")
    assert_equal(result.getvalue(0,0).to_i, 5)
  end
end