在 Rspec 中存根 ActionMailer

Question

问候！
我正在尝试使用如下所示的 Rspec 测试控制器方法：

def email_customer
  @quote = Quote.find(params[:quote_id])
  hash = {
    quote: @quote,
    body: params[:email_body],
    subject: params[:email_subject]
  }
  QuoteMailer.email_customer(hash).deliver
  redirect_to edit_quote_path params[:quote_id]
end

相应的规范如下所示：

describe 'POST email_customer' do
  let!(:quote) { create(:valid_quote) }
  it 'assigns the quote and sends the customer an email' do
    post :email_customer, quote_id: quote.id
    expect(assigns(:quote)).to eq(quote)
    expect(QuoteMailer).to receive(:email_customer).with(an_instance_of(Hash)).and_return( double('QuoteMailer', deliver: true))
  end
end

当测试运行时，我收到以下消息：

Failure/Error: expect(QuoteMailer).to receive(:email_customer).with(an_instance_of(Hash)).and_return( double('QuoteMailer', deliver: true))
       (<QuoteMailer (class)>).email_customer(an instance of Hash)
           expected: 1 time with arguments: (#<RSpec::Matchers::AliasedMatcher:0x0000000c2b1e28 @description_block=#<Proc:0x00000009816268@/home/david/.rvm/gems/ruby-2.1.1/gems/rspec-expectations-3.0.0.beta2/lib/rspec/matchers.rb:231 (lambda)>, @base_matcher=#<RSpec::Matchers::BuiltIn::BeAnInstanceOf:0x0000000c2b1e50 @expected=Hash>>)
           received: 0 times with arguments: (#<RSpec::Matchers::AliasedMatcher:0x0000000c2b1e28 @description_block=#<Proc:0x00000009816268@/home/david/.rvm/gems/ruby-2.1.1/gems/rspec-expectations-3.0.0.beta2/lib/rspec/matchers.rb:231 (lambda)>, @base_matcher=#<RSpec::Matchers::BuiltIn::BeAnInstanceOf:0x0000000c2b1e50 @expected=Hash>>)
     # ./spec/controllers/quotes_controller_spec.rb:28:in `block (3 levels) in <top (required)>'

我在控制器方法和 email_customer 方法中分散了 puts 语句，所以我知道它最终会运行它的过程并使用正确的方法，但我不确定它为什么会失败。我猜这是一个我不确定的愚蠢的语法错误。提前感谢您的帮助！

Answer 1

消息expectations 应该出现在您要测试的方法的调用之前，因为它们实际上是在对象中存根消息：

describe 'POST email_customer' do
  let!(:quote) { create(:valid_quote) }
  it 'assigns the quote and sends the customer an email' do
    expect(QuoteMailer).to receive(:email_customer).with(an_instance_of(Hash)).and_return( double('QuoteMailer', deliver: true))

    post :email_customer, quote_id: quote.id

    expect(assigns(:quote)).to eq(quote)
  end
end