接收次数

当预期消息时，你可以指定预期消息接收的次数

* `expect(...).to receive(...).once`
* `expect(...).to receive(...).twice`
* `expect(...).to receive(...).exactly(n).time`
* `expect(...).to receive(...).exactly(n).times`
* `expect(...).to receive(...).at_least(:once)`
* `expect(...).to receive(...).at_least(:twice)`
* `expect(...).to receive(...).at_least(n).time`
* `expect(...).to receive(...).at_least(n).times`
* `expect(...).to receive(...).at_most(:once)`
* `expect(...).to receive(...).at_most(:twice)`
* `expect(...).to receive(...).at_most(n).time`
* `expect(...).to receive(...).at_most(n).times`

如果你没有指定预期的接收次数，则默认为 `once`。

背景

给定一个名为 “lib/account.rb” 的文件，内容为

class Account
  def initialize(logger)
    @logger = logger
  end

  def open
    @logger.account_opened
  end
end

通过示例

给定一个名为 “spec/account_spec.rb” 的文件，内容为

require 'account'

RSpec.describe Account do
  let(:logger)  { double("Logger") }
  let(:account) { Account.new(logger) }

  example "once" do
    expect(logger).to receive(:account_opened).once
    account.open
  end

  example "twice" do
    expect(logger).to receive(:account_opened).twice
    account.open
    account.open
  end

  example "exactly(n).time" do
    expect(logger).to receive(:account_opened).exactly(1).time
    account.open
  end

  example "exactly(n).times" do
    expect(logger).to receive(:account_opened).exactly(3).times
    account.open
    account.open
    account.open
  end

  example "at_least(:once)" do
    expect(logger).to receive(:account_opened).at_least(:once)
    account.open
    account.open
  end

  example "at_least(:twice)" do
    expect(logger).to receive(:account_opened).at_least(:twice)
    account.open
    account.open
    account.open
  end

  example "at_least(n).time" do
    expect(logger).to receive(:account_opened).at_least(1).time
    account.open
  end

  example "at_least(n).times" do
    expect(logger).to receive(:account_opened).at_least(3).times
    account.open
    account.open
    account.open
    account.open
  end

  example "at_most(:once)" do
    expect(logger).to receive(:account_opened).at_most(:once)
  end

  example "at_most(:twice)" do
    expect(logger).to receive(:account_opened).at_most(:twice)
    account.open
  end

  example "at_most(n).time" do
    expect(logger).to receive(:account_opened).at_most(1).time
    account.open
  end

  example "at_most(n).times" do
    expect(logger).to receive(:account_opened).at_most(3).times
    account.open
    account.open
  end
end

当我运行 rspec spec/account_spec.rb

那么这些示例应该全部通过。

失败示例

给定一个名为 “spec/account_spec.rb” 的文件，内容为

require 'account'

RSpec.describe Account do
  let(:logger)  { double("Logger") }
  let(:account) { Account.new(logger) }

  example "once" do
    expect(logger).to receive(:account_opened).once
    account.open
    account.open
  end

  example "twice" do
    expect(logger).to receive(:account_opened).twice
    account.open
  end

  example "exactly(n).times" do
    expect(logger).to receive(:account_opened).exactly(3).times
    account.open
    account.open
  end

  example "at_least(:once)" do
    expect(logger).to receive(:account_opened).at_least(:once)
  end

  example "at_least(:twice)" do
    expect(logger).to receive(:account_opened).at_least(:twice)
    account.open
  end

  example "at_least(n).times" do
    expect(logger).to receive(:account_opened).at_least(3).times
    account.open
    account.open
  end

  example "at_most(:once)" do
    expect(logger).to receive(:account_opened).at_most(:once)
    account.open
    account.open
  end

  example "at_most(:twice)" do
    expect(logger).to receive(:account_opened).at_most(:twice)
    account.open
    account.open
    account.open
  end

  example "at_most(n).times" do
    expect(logger).to receive(:account_opened).at_most(3).times
    account.open
    account.open
    account.open
    account.open
  end
end

当我运行 rspec spec/account_spec.rb --order defined

那么这些示例应该全部失败，并输出以下内容


预期：1 次，使用任何参数
接收：2 次

预期：2 次，使用任何参数
接收：1 次，使用任何参数

预期：3 次，使用任何参数
接收：2 次，使用任何参数

预期：至少 1 次，使用任何参数
接收：0 次，使用任何参数

预期：至少 2 次，使用任何参数
接收：1 次，使用任何参数

预期：至少 3 次，使用任何参数
接收：2 次，使用任何参数

预期：最多 1 次，使用任何参数
接收：2 次

预期：最多 2 次，使用任何参数
接收：3 次

预期：最多 3 次，使用任何参数
接收：4 次