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.



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# File 'lib/rspec/mocks/message_expectation.rb', line 95

def and_call_original
  and_wrap_original 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.



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# File 'lib/rspec/mocks/message_expectation.rb', line 145

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 67

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 161

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 113

def and_wrap_original(&block)
  if RSpec::Mocks::TestDouble === @method_double.object
    @error_generator.raise_only_valid_on_a_partial_double(:and_call_original)
  else
    warn_about_stub_override if implementation.inner_action
    @implementation = AndWrapOriginalImplementation.new(@method_double.original_method, block)
    @yield_receiver_to_implementation_block = false
  end

  nil
end

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

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:

  • (MessageExpecation)

    self, to support further chaining.



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# File 'lib/rspec/mocks/message_expectation.rb', line 173

def and_yield(*args, &block)
  raise_already_invoked_error_if_necessary(__method__)
  yield @eval_context = Object.new if block
  @args_to_yield << args
  self.initial_implementation_action = AndYieldImplementation.new(@args_to_yield, @eval_context, @error_generator)
  self
end

#at_least(n, &block) ⇒ MessageExpecation

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:

  • (MessageExpecation)

    self, to support further chaining.



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# File 'lib/rspec/mocks/message_expectation.rb', line 203

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) ⇒ MessageExpecation

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:

  • (MessageExpecation)

    self, to support further chaining.



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# File 'lib/rspec/mocks/message_expectation.rb', line 222

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) ⇒ MessageExpecation

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

Examples:

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

Returns:

  • (MessageExpecation)

    self, to support further chaining.



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# File 'lib/rspec/mocks/message_expectation.rb', line 190

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

#neverMessageExpecation

Expect a message not to be received at all.

Examples:

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

Returns:

  • (MessageExpecation)

    self, to support further chaining.



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# File 'lib/rspec/mocks/message_expectation.rb', line 246

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

#once(&block) ⇒ MessageExpecation

Expect a message to be received exactly one time.

Examples:

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

Returns:

  • (MessageExpecation)

    self, to support further chaining.



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# File 'lib/rspec/mocks/message_expectation.rb', line 257

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

#ordered(&block) ⇒ MessageExpecation

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:

  • (MessageExpecation)

    self, to support further chaining.



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# File 'lib/rspec/mocks/message_expectation.rb', line 331

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

#thrice(&block) ⇒ MessageExpecation

Expect a message to be received exactly three times.

Examples:

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

Returns:

  • (MessageExpecation)

    self, to support further chaining.



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# File 'lib/rspec/mocks/message_expectation.rb', line 279

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

#times(&block) ⇒ MessageExpecation

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:

  • (MessageExpecation)

    self, to support further chaining.



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# File 'lib/rspec/mocks/message_expectation.rb', line 236

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

#twice(&block) ⇒ MessageExpecation

Expect a message to be received exactly two times.

Examples:

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

Returns:

  • (MessageExpecation)

    self, to support further chaining.



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# File 'lib/rspec/mocks/message_expectation.rb', line 268

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

#with(*args, &block) ⇒ MessageExpecation

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:

  • (MessageExpecation)

    self, to support further chaining.



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# File 'lib/rspec/mocks/message_expectation.rb', line 312

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