Receive Counts

When expecting a message, you can specify how many times you expect the message to be received:

* `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`

If you don’t specify an expected receive count, it defaults to once.

Background

Given a file named “lib/account.rb” with:

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

  def open
    @logger.account_opened
  end
end

Passing examples

Given a file named “spec/account_spec.rb” with:

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

When I run rspec spec/account_spec.rb

Then the examples should all pass.

Failing examples

Given a file named “spec/account_spec.rb” with:

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

When I run rspec spec/account_spec.rb --order defined

Then the examples should all fail, producing the following output:


expected: 1 time with any arguments
received: 2 times

expected: 2 times with any arguments
received: 1 time with any arguments

expected: 3 times with any arguments
received: 2 times with any arguments

expected: at least 1 time with any arguments
received: 0 times with any arguments

expected: at least 2 times with any arguments
received: 1 time with any arguments

expected: at least 3 times with any arguments
received: 2 times with any arguments

expected: at most 1 time with any arguments
received: 2 times

expected: at most 2 times with any arguments
received: 3 times

expected: at most 3 times with any arguments
received: 4 times