Class: RSpec::Mocks::MessageExpectation

Inherits:
Object
  • Object
show all
Defined in:
lib/rspec/mocks/message_expectation.rb

Overview

Represents an individual method stub or message expectation. The methods defined here can be used to configure how it behaves. The methods return self so that they can be chained together to form a fluent interface.

Direct Known Subclasses

VerifyingMessageExpectation

Configuring Responses collapse

Constraining Receive Counts collapse

Other Constraints collapse

Instance Method Details

#and_call_originalnil

Note:

This is only available on partial doubles.

Tells the object to delegate to the original unmodified method when it receives the message.

Examples:

expect(counter).to receive(:increment).and_call_original
original_count = counter.count
counter.increment
expect(counter.count).to eq(original_count + 1)

Returns:

  • (nil)

    No further chaining is supported after this.


99
100
101
102
103
# File 'lib/rspec/mocks/message_expectation.rb', line 99

def and_call_original
  wrap_original(__method__) do |original, *args, &block|
    original.call(*args, &block)
  end
end

#and_raisenil #and_raise(ExceptionClass) ⇒ nil #and_raise(ExceptionClass, message) ⇒ nil #and_raise(exception_instance) ⇒ nil

Note:

When you pass an exception class, the MessageExpectation will raise an instance of it, creating it with exception and passing message if specified. If the exception class initializer requires more than one parameters, you must pass in an instance and not the class, otherwise this method will raise an ArgumentError exception.

Tells the object to raise an exception when the message is received.

Examples:

allow(car).to receive(:go).and_raise
allow(car).to receive(:go).and_raise(OutOfGas)
allow(car).to receive(:go).and_raise(OutOfGas, "At least 2 oz of gas needed to drive")
allow(car).to receive(:go).and_raise(OutOfGas.new(2, :oz))

Returns:

  • (nil)

    No further chaining is supported after this.


141
142
143
144
145
# File 'lib/rspec/mocks/message_expectation.rb', line 141

def and_raise(*args)
  raise_already_invoked_error_if_necessary(__method__)
  self.terminal_implementation_action = Proc.new { raise(*args) }
  nil
end

#and_return(value) ⇒ nil #and_return(first_value, second_value) ⇒ nil

Tells the object to return a value when it receives the message. Given more than one value, the first value is returned the first time the message is received, the second value is returned the next time, etc, etc.

If the message is received more times than there are values, the last value is received for every subsequent call.

Examples:

allow(counter).to receive(:count).and_return(1)
counter.count # => 1
counter.count # => 1

allow(counter).to receive(:count).and_return(1,2,3)
counter.count # => 1
counter.count # => 2
counter.count # => 3
counter.count # => 3
counter.count # => 3
# etc

Returns:

  • (nil)

    No further chaining is supported after this.


71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
# File 'lib/rspec/mocks/message_expectation.rb', line 71

def and_return(first_value, *values)
  raise_already_invoked_error_if_necessary(__method__)
  if negative?
    raise "`and_return` is not supported with negative message expectations"
  end

  if block_given?
    raise ArgumentError, "Implementation blocks aren't supported with `and_return`"
  end

  values.unshift(first_value)
  @expected_received_count = [@expected_received_count, values.size].max unless ignoring_args? || (@expected_received_count == 0 && @at_least)
  self.terminal_implementation_action = AndReturnImplementation.new(values)

  nil
end

#and_throw(symbol) ⇒ nil #and_throw(symbol, object) ⇒ nil

Tells the object to throw a symbol (with the object if that form is used) when the message is received.

Examples:

allow(car).to receive(:go).and_throw(:out_of_gas)
allow(car).to receive(:go).and_throw(:out_of_gas, :level => 0.1)

Returns:

  • (nil)

    No further chaining is supported after this.


157
158
159
160
161
# File 'lib/rspec/mocks/message_expectation.rb', line 157

def and_throw(*args)
  raise_already_invoked_error_if_necessary(__method__)
  self.terminal_implementation_action = Proc.new { throw(*args) }
  nil
end

#and_wrap_original(&block) ⇒ nil

Note:

This is only available on partial doubles.

Decorates the stubbed method with the supplied block. The original unmodified method is passed to the block along with any method call arguments so you can delegate to it, whilst still being able to change what args are passed to it and/or change the return value.

Examples:

expect(api).to receive(:large_list).and_wrap_original do |original_method, *args, &block|
  original_method.call(*args, &block).first(10)
end

Returns:

  • (nil)

    No further chaining is supported after this.


117
118
119
# File 'lib/rspec/mocks/message_expectation.rb', line 117

def and_wrap_original(&block)
  wrap_original(__method__, &block)
end

#and_yield(*args) {|@eval_context = Object.new| ... } ⇒ MessageExpectation

Tells the object to yield one or more args to a block when the message is received.

Examples:

stream.stub(:open).and_yield(StringIO.new)

Yields:

  • (@eval_context = Object.new)

Returns:


169
170
171
172
173
174
175
176
177
178
179
180
# File 'lib/rspec/mocks/message_expectation.rb', line 169

def and_yield(*args, &block)
  raise_already_invoked_error_if_necessary(__method__)
  yield @eval_context = Object.new if block

  # Initialize args to yield now that it's being used, see also: comment
  # in constructor.
  @args_to_yield ||= []

  @args_to_yield << args
  self.initial_implementation_action = AndYieldImplementation.new(@args_to_yield, @eval_context, @error_generator)
  self
end

#at_least(n, &block) ⇒ MessageExpectation

Constrain a message expectation to be received at least a specific number of times.

Examples:

expect(dealer).to receive(:deal_card).at_least(9).times

Returns:


204
205
206
207
208
209
210
211
212
213
214
215
# File 'lib/rspec/mocks/message_expectation.rb', line 204

def at_least(n, &block)
  raise_already_invoked_error_if_necessary(__method__)
  set_expected_received_count :at_least, n

  if n == 0
    raise "at_least(0) has been removed, use allow(...).to receive(:message) instead"
  end

  self.inner_implementation_action = block

  self
end

#at_most(n, &block) ⇒ MessageExpectation

Constrain a message expectation to be received at most a specific number of times.

Examples:

expect(dealer).to receive(:deal_card).at_most(10).times

Returns:


223
224
225
226
227
228
# File 'lib/rspec/mocks/message_expectation.rb', line 223

def at_most(n, &block)
  raise_already_invoked_error_if_necessary(__method__)
  self.inner_implementation_action = block
  set_expected_received_count :at_most, n
  self
end

#exactly(n, &block) ⇒ MessageExpectation

Constrain a message expectation to be received a specific number of times.

Examples:

expect(dealer).to receive(:deal_card).exactly(10).times

Returns:


191
192
193
194
195
196
# File 'lib/rspec/mocks/message_expectation.rb', line 191

def exactly(n, &block)
  raise_already_invoked_error_if_necessary(__method__)
  self.inner_implementation_action = block
  set_expected_received_count :exactly, n
  self
end

#neverMessageExpectation

Expect a message not to be received at all.

Examples:

expect(car).to receive(:stop).never

Returns:


248
249
250
251
252
# File 'lib/rspec/mocks/message_expectation.rb', line 248

def never
  error_generator.raise_double_negation_error("expect(obj)") if negative?
  @expected_received_count = 0
  self
end

#once(&block) ⇒ MessageExpectation

Expect a message to be received exactly one time.

Examples:

expect(car).to receive(:go).once

Returns:


259
260
261
262
263
# File 'lib/rspec/mocks/message_expectation.rb', line 259

def once(&block)
  self.inner_implementation_action = block
  set_expected_received_count :exactly, 1
  self
end

#ordered(&block) ⇒ MessageExpectation

Expect messages to be received in a specific order.

Examples:

expect(api).to receive(:prepare).ordered
expect(api).to receive(:run).ordered
expect(api).to receive(:finish).ordered

Returns:


333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
# File 'lib/rspec/mocks/message_expectation.rb', line 333

def ordered(&block)
  if type == :stub
    RSpec.warning(
      "`allow(...).to receive(..).ordered` is not supported and will " \
      "have no effect, use `and_return(*ordered_values)` instead."
    )
  end

  self.inner_implementation_action = block
  additional_expected_calls.times do
    @order_group.register(self)
  end
  @ordered = true
  self
end

#thrice(&block) ⇒ MessageExpectation

Expect a message to be received exactly three times.

Examples:

expect(car).to receive(:go).thrice

Returns:


281
282
283
284
285
# File 'lib/rspec/mocks/message_expectation.rb', line 281

def thrice(&block)
  self.inner_implementation_action = block
  set_expected_received_count :exactly, 3
  self
end

#times(&block) ⇒ MessageExpectation Also known as: time

Syntactic sugar for exactly, at_least and at_most

Examples:

expect(dealer).to receive(:deal_card).exactly(10).times
expect(dealer).to receive(:deal_card).at_least(10).times
expect(dealer).to receive(:deal_card).at_most(10).times

Returns:


237
238
239
240
# File 'lib/rspec/mocks/message_expectation.rb', line 237

def times(&block)
  self.inner_implementation_action = block
  self
end

#to_sString Also known as: inspect

Returns a nice representation of the message expectation

Returns:

  • (String)

    a nice representation of the message expectation


350
351
352
353
354
# File 'lib/rspec/mocks/message_expectation.rb', line 350

def to_s
  args_description = error_generator.method_call_args_description(@argument_list_matcher.expected_args, "", "") { true }
  args_description = "(#{args_description})" unless args_description.start_with?("(")
  "#<#{self.class} #{error_generator.intro}.#{message}#{args_description}>"
end

#twice(&block) ⇒ MessageExpectation

Expect a message to be received exactly two times.

Examples:

expect(car).to receive(:go).twice

Returns:


270
271
272
273
274
# File 'lib/rspec/mocks/message_expectation.rb', line 270

def twice(&block)
  self.inner_implementation_action = block
  set_expected_received_count :exactly, 2
  self
end

#with(*args, &block) ⇒ MessageExpectation

Constrains a stub or message expectation to invocations with specific arguments.

With a stub, if the message might be received with other args as well, you should stub a default value first, and then stub or mock the same message using with to constrain to specific arguments.

A message expectation will fail if the message is received with different arguments.

Examples:

allow(cart).to receive(:add) { :failure }
allow(cart).to receive(:add).with(Book.new(:isbn => 1934356379)) { :success }
cart.add(Book.new(:isbn => 1234567890))
# => :failure
cart.add(Book.new(:isbn => 1934356379))
# => :success

expect(cart).to receive(:add).with(Book.new(:isbn => 1934356379)) { :success }
cart.add(Book.new(:isbn => 1234567890))
# => failed expectation
cart.add(Book.new(:isbn => 1934356379))
# => passes

Returns:


314
315
316
317
318
319
320
321
322
323
324
# File 'lib/rspec/mocks/message_expectation.rb', line 314

def with(*args, &block)
  raise_already_invoked_error_if_necessary(__method__)
  if args.empty?
    raise ArgumentError,
          "`with` must have at least one argument. Use `no_args` matcher to set the expectation of receiving no arguments."
  end

  self.inner_implementation_action = block
  @argument_list_matcher = ArgumentListMatcher.new(*args)
  self
end