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_original ⇒ nil

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.

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# File 'lib/rspec/mocks/message_expectation.rb', line 97
def and_call_original
  wrap_original(__method__) do |original, *args, &block|
    original.call(*args, &block)
  end
end

#and_raise ⇒ nil #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.

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# File 'lib/rspec/mocks/message_expectation.rb', line 139
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.

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# File 'lib/rspec/mocks/message_expectation.rb', line 69
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.

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# File 'lib/rspec/mocks/message_expectation.rb', line 155
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.

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# File 'lib/rspec/mocks/message_expectation.rb', line 115
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:

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# File 'lib/rspec/mocks/message_expectation.rb', line 167
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:

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# File 'lib/rspec/mocks/message_expectation.rb', line 202
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:

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# File 'lib/rspec/mocks/message_expectation.rb', line 221
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:

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# File 'lib/rspec/mocks/message_expectation.rb', line 189
def exactly(n, &block)
  raise_already_invoked_error_if_necessary(__method__)
  self.inner_implementation_action = block
  set_expected_received_count :exactly, n
  self
end

#never ⇒ MessageExpectation

Expect a message not to be received at all.

Examples:

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

Returns:

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# File 'lib/rspec/mocks/message_expectation.rb', line 245
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:

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# File 'lib/rspec/mocks/message_expectation.rb', line 256
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:

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# File 'lib/rspec/mocks/message_expectation.rb', line 330
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:

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# File 'lib/rspec/mocks/message_expectation.rb', line 278
def thrice(&block)
  self.inner_implementation_action = block
  set_expected_received_count :exactly, 3
  self
end

#times(&block) ⇒ MessageExpectation

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:

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# File 'lib/rspec/mocks/message_expectation.rb', line 235
def times(&block)
  self.inner_implementation_action = block
  self
end

#to_s ⇒ String Also known as: inspect

Returns a nice representation of the message expectation.

Returns:

  • (String) —

    a nice representation of the message expectation

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# File 'lib/rspec/mocks/message_expectation.rb', line 347
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:

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# File 'lib/rspec/mocks/message_expectation.rb', line 267
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:

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# File 'lib/rspec/mocks/message_expectation.rb', line 311
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