为factory_girl（数据映射器）中的has_many关联声明：child_key

Question

我在 ror 应用程序中使用 datamapper 和 postgres，在我的模型中我有这样的关联：

#/models/account.rb
 has n, :transfers_out, "Transfer", :child_key => [ :account_from_id ]  
 has n, :transfers_in, "Transfer", :child_key => [ :account_to_id ]  

#/models/transfer.rb
 belongs_to :account_from, "Account", :child_key => [:account_from_id], :required => true
 belongs_to :account_to, "Account",   :child_key => [:account_to_id], :required => false

现在我需要使用 Factory Girl 在 rspec 中进行测试。所以，我写了这个：

#/factories/account.rb
Factory.define :account do |f|
  f.transfers_out {|transfer| [transfer.association(:transfer)]}
  f.transfers_in  {|transfer| [transfer.association(:transfer)]}
  f.amount "0"
end

  Factory.define :account_big, :class => :account do |f|
    f.name "MyMillionDollarPresent"
    f.amount "10000"
  end

Factory.define :account_small, :class => :account do |f|
  f.name "PoorHomo"
  f.amount "100"
end 

和小转账工厂

Factory.define :transfer do |f|
f.id "1"
f.comment  "payment"
f.status  "proposed"
f.amount "0"
end

所以，我尝试测试从帐户创建转账：

    describe Transfer do

  before(:each) do
    @account_big = Factory(:account_big)
    @account_small = Factory(:account_small)
    @transfer = Factory(:transfer)
  end

  it "should debit buyer" do
    @buyer = @account_big
    @buyer.transfers_out = @transfer
    @transfer.amount = 3000
    @buyer.amount -= @transfer.amount
    @buyer.amount.should == 7000
  end

但这导致我测试失败：

 1) Transfer should debit buyer
     Failure/Error: @buyer.transfers_out = @transfer
     TypeError:
       can't convert Transfer into Array
     # ./spec/models/transfer_spec.rb:15:in `block (2 levels) in <top (required)>'

Soo，我应该做什么以及我应该如何声明与孩子的关联在这种情况下关键？将不胜感激任何帮助。

Answer 1

@buyer.transfers_out 是一个数组，@transfer 是单个对象。如果您想创建一个只有一个元素的数组，您应该使用 @buyer.transfers_out = [ @transfer ] 或类似 @buyer.transfers_out << @转移。