ruby-on-rails - Rspec:隐式定义的主题

Question

Rspec implicitly defined subject documentation说:

While the examples below demonstrate how subject can be used as a user-facing concept, we recommend that you reserve it for support of custom matchers and/or extension libraries that hide its use from examples.

这是否意味着，我应该尽量不称呼“主题”。直接在我的规范？如果是，我应该使用什么作为主题对象？

Answer 1

比较这两个例子:

describe "User" do
  subject { User.new(age: 42) }
  specify { subject.age.should == 42 }
  its(:age) { should == 42 }
end

describe "User" do
  let(:user) { User.new(age: 42) }
  specify { user.age.should == 42 }
end

更新

Rspec 中有一个很酷的特性——命名主题:

这是一个 example来自 David Chelimsky:

describe CheckingAccount, "with a non-zero starting balance" do
  subject(:account) { CheckingAccount.new(Money.new(50, :USD)) }
  it { should_not be_overdrawn }
  it "has a balance equal to the starting balance" do
    account.balance.should eq(Money.new(50, :USD))
  end
end

当您使用 user 而不是 subject 时，它更具可读性(恕我直言)。但是 subject 让你可以使用很好的扩展 its(:age)。