Class Mocha::Expectation
In: lib/mocha/expectation.rb
Parent: Object

Methods on expectations returned from {Mock#expects}, {Mock#stubs}, {ObjectMethods#expects} and {ObjectMethods#stubs}.

Methods

Attributes

backtrace  [R]  @private

Public Class methods

Public Instance methods

Modifies expectation so that the expected method must be called at least a minimum_number_of_times.

@param [Integer] minimum_number_of_times minimum number of expected invocations. @return [Expectation] the same expectation, thereby allowing invocations of other {Expectation} methods to be chained.

@example Expected method must be called at least twice.

  object = mock()
  object.expects(:expected_method).at_least(2)
  3.times { object.expected_method }
  # => verify succeeds

  object = mock()
  object.expects(:expected_method).at_least(2)
  object.expected_method
  # => verify fails

Modifies expectation so that the expected method must be called at least once.

@return [Expectation] the same expectation, thereby allowing invocations of other {Expectation} methods to be chained.

@example Expected method must be called at least once.

  object = mock()
  object.expects(:expected_method).at_least_once
  object.expected_method
  # => verify succeeds

  object = mock()
  object.expects(:expected_method).at_least_once
  # => verify fails

Modifies expectation so that the expected method must be called at most a maximum_number_of_times.

@param [Integer] maximum_number_of_times maximum number of expected invocations. @return [Expectation] the same expectation, thereby allowing invocations of other {Expectation} methods to be chained.

@example Expected method must be called at most twice.

  object = mock()
  object.expects(:expected_method).at_most(2)
  2.times { object.expected_method }
  # => verify succeeds

  object = mock()
  object.expects(:expected_method).at_most(2)
  3.times { object.expected_method } # => unexpected invocation

Modifies expectation so that the expected method must be called at most once.

@return [Expectation] the same expectation, thereby allowing invocations of other {Expectation} methods to be chained.

@example Expected method must be called at most once.

  object = mock()
  object.expects(:expected_method).at_most_once
  object.expected_method
  # => verify succeeds

  object = mock()
  object.expects(:expected_method).at_most_once
  2.times { object.expected_method } # => unexpected invocation

Constrains the expectation so that it must be invoked at the current point in the sequence.

To expect a sequence of invocations, write the expectations in order and add the +in_sequence(sequence)+ clause to each one.

Expectations in a sequence can have any invocation count.

If an expectation in a sequence is stubbed, rather than expected, it can be skipped in the sequence.

An expected method can appear in multiple sequences.

@param [*Array<Sequence>] sequences sequences in which expected method should appear. @return [Expectation] the same expectation, thereby allowing invocations of other {Expectation} methods to be chained.

@see API#sequence

@example Ensure methods are invoked in a specified order.

  breakfast = sequence('breakfast')

  egg = mock('egg')
  egg.expects(:crack).in_sequence(breakfast)
  egg.expects(:fry).in_sequence(breakfast)
  egg.expects(:eat).in_sequence(breakfast)

@private

Modifies expectation so that when the expected method is called, it yields multiple times per invocation with the specified parameter_groups.

@param [*Array<Array>] parameter_groups each element of parameter_groups should iself be an Array representing the parameters to be passed to the block for a single yield. @return [Expectation] the same expectation, thereby allowing invocations of other {Expectation} methods to be chained. @see then

@example When the expected_method is called, the stub will invoke the block twice, the first time it passes +’result_1’+, +’result_2’+ as the parameters, and the second time it passes ‘result_3’ as the parameters.

  object = mock()
  object.expects(:expected_method).multiple_yields(['result_1', 'result_2'], ['result_3'])
  yielded_values = []
  object.expected_method { |*values| yielded_values << values }
  yielded_values # => [['result_1', 'result_2'], ['result_3]]

@example Yield different groups of parameters on different invocations of the expected method.

  object = mock()
  object.stubs(:expected_method).multiple_yields([1, 2], [3]).then.multiple_yields([4], [5, 6])
  yielded_values_from_first_invocation = []
  yielded_values_from_second_invocation = []
  object.expected_method { |*values| yielded_values_from_first_invocation << values } # first invocation
  object.expected_method { |*values| yielded_values_from_second_invocation << values } # second invocation
  yielded_values_from_first_invocation # => [[1, 2], [3]]
  yielded_values_from_second_invocation # => [[4], [5, 6]]

Modifies expectation so that the expected method must never be called.

@return [Expectation] the same expectation, thereby allowing invocations of other {Expectation} methods to be chained.

@example Expected method must never be called.

  object = mock()
  object.expects(:expected_method).never
  object.expected_method # => unexpected invocation

  object = mock()
  object.expects(:expected_method).never
  # => verify succeeds

Modifies expectation so that the expected method must be called exactly once.

Note that this is the default behaviour for an expectation, but you may wish to use it for clarity/emphasis.

@return [Expectation] the same expectation, thereby allowing invocations of other {Expectation} methods to be chained.

@example Expected method must be invoked exactly once.

  object = mock()
  object.expects(:expected_method).once
  object.expected_method
  # => verify succeeds

  object = mock()
  object.expects(:expected_method).once
  object.expected_method
  object.expected_method # => unexpected invocation

  object = mock()
  object.expects(:expected_method).once
  # => verify fails

Modifies expectation so that when the expected method is called, it raises the specified exception with the specified message i.e. calls +Kernel#raise(exception, message)+.

@param [Class,Exception,String,exception] exception exception to be raised or message to be passed to RuntimeError. @param [String] message exception message. @return [Expectation] the same expectation, thereby allowing invocations of other {Expectation} methods to be chained.

@see Kernel#raise @see then

@overload def raises @overload def raises(exception) @overload def raises(exception, message)

@example Raise specified exception if expected method is invoked.

  object = stub()
  object.stubs(:expected_method).raises(Exception, 'message')
  object.expected_method # => raises exception of class Exception and with message 'message'

@example Raise custom exception with extra constructor parameters by passing in an instance of the exception.

  object = stub()
  object.stubs(:expected_method).raises(MyException.new('message', 1, 2, 3))
  object.expected_method # => raises the specified instance of MyException

@example Raise different exceptions on consecutive invocations of the expected method.

  object = stub()
  object.stubs(:expected_method).raises(Exception1).then.raises(Exception2)
  object.expected_method # => raises exception of class Exception1
  object.expected_method # => raises exception of class Exception2

@example Raise an exception on first invocation of expected method and then return values on subsequent invocations.

  object = stub()
  object.stubs(:expected_method).raises(Exception).then.returns(2, 3)
  object.expected_method # => raises exception of class Exception1
  object.expected_method # => 2
  object.expected_method # => 3

Modifies expectation so that when the expected method is called, it returns the specified value.

@return [Expectation] the same expectation, thereby allowing invocations of other {Expectation} methods to be chained. @see then

@overload def returns(value)

  @param [Object] value value to return on invocation of expected method.

@overload def returns(*values)

  @param [*Array] values values to return on consecutive invocations of expected method.

@example Return the same value on every invocation.

  object = mock()
  object.stubs(:stubbed_method).returns('result')
  object.stubbed_method # => 'result'
  object.stubbed_method # => 'result'

@example Return a different value on consecutive invocations.

  object = mock()
  object.stubs(:stubbed_method).returns(1, 2)
  object.stubbed_method # => 1
  object.stubbed_method # => 2

@example Alternative way to return a different value on consecutive invocations.

  object = mock()
  object.stubs(:expected_method).returns(1, 2).then.returns(3)
  object.expected_method # => 1
  object.expected_method # => 2
  object.expected_method # => 3

@example May be called in conjunction with {raises} on the same expectation.

  object = mock()
  object.stubs(:expected_method).returns(1, 2).then.raises(Exception)
  object.expected_method # => 1
  object.expected_method # => 2
  object.expected_method # => raises exception of class Exception1

@example Note that in Ruby a method returning multiple values is exactly equivalent to a method returning an Array of those values.

  object = mock()
  object.stubs(:expected_method).returns([1, 2])
  x, y = object.expected_method
  x # => 1
  y # => 2

@overload def then

  Used as syntactic sugar to improve readability. It has no effect on state of the expectation.

@overload def then(state_machine.is(state_name))

  Used to change the +state_machine+ to the state specified by +state_name+ when the expected invocation occurs.
  @param [StateMachine::State] state_machine.is(state_name) provides a mechanism to change the +state_machine+ into the state specified by +state_name+ when the expected method is invoked.

  @see API#states
  @see StateMachine
  @see #when

@return [Expectation] the same expectation, thereby allowing invocations of other {Expectation} methods to be chained.

@example Using {then} as syntactic sugar when specifying values to be returned and exceptions to be raised on consecutive invocations of the expected method.

  object = mock()
  object.stubs(:expected_method).returns(1, 2).then.raises(Exception).then.returns(4)
  object.expected_method # => 1
  object.expected_method # => 2
  object.expected_method # => raises exception of class Exception
  object.expected_method # => 4

@example Using {then} to change the state of a state_machine on the invocation of an expected method.

  power = states('power').starts_as('off')

  radio = mock('radio')
  radio.expects(:switch_on).then(power.is('on'))
  radio.expects(:select_channel).with('BBC Radio 4').when(power.is('on'))
  radio.expects(:adjust_volume).with(+5).when(power.is('on'))
  radio.expects(:select_channel).with('BBC World Service').when(power.is('on'))
  radio.expects(:adjust_volume).with(-5).when(power.is('on'))
  radio.expects(:switch_off).then(power.is('off'))

Modifies expectation so that when the expected method is called, it throws the specified tag with the specific return value object i.e. calls +Kernel#throw(tag, object)+.

@param [Symbol,String] tag tag to throw to transfer control to the active catch block. @param [Object] object return value for the catch block. @return [Expectation] the same expectation, thereby allowing invocations of other {Expectation} methods to be chained.

@see Kernel#throw @see then

@overload def throw(tag) @overload def throw(tag, object)

@example Throw tag when expected method is invoked.

  object = stub()
  object.stubs(:expected_method).throws(:done)
  object.expected_method # => throws tag :done

@example Throw tag with return value object c.f. +Kernel#throw+.

  object = stub()
  object.stubs(:expected_method).throws(:done, 'result')
  object.expected_method # => throws tag :done and causes catch block to return 'result'

@example Throw different tags on consecutive invocations of the expected method.

  object = stub()
  object.stubs(:expected_method).throws(:done).then.throws(:continue)
  object.expected_method # => throws :done
  object.expected_method # => throws :continue

@example Throw tag on first invocation of expected method and then return values for subsequent invocations.

  object = stub()
  object.stubs(:expected_method).throws(:done).then.returns(2, 3)
  object.expected_method # => throws :done
  object.expected_method # => 2
  object.expected_method # => 3

Modifies expectation so that the number of calls to the expected method must be within a specific range.

@param [Range,Integer] range specifies the allowable range in the number of expected invocations. @return [Expectation] the same expectation, thereby allowing invocations of other {Expectation} methods to be chained.

@example Specifying a specific number of expected invocations.

  object = mock()
  object.expects(:expected_method).times(3)
  3.times { object.expected_method }
  # => verify succeeds

  object = mock()
  object.expects(:expected_method).times(3)
  2.times { object.expected_method }
  # => verify fails

@example Specifying a range in the number of expected invocations.

  object = mock()
  object.expects(:expected_method).times(2..4)
  3.times { object.expected_method }
  # => verify succeeds

  object = mock()
  object.expects(:expected_method).times(2..4)
  object.expected_method
  # => verify fails

Modifies expectation so that the expected method must be called exactly twice.

@return [Expectation] the same expectation, thereby allowing invocations of other {Expectation} methods to be chained.

@example Expected method must be invoked exactly twice.

  object = mock()
  object.expects(:expected_method).twice
  object.expected_method
  object.expected_method
  # => verify succeeds

  object = mock()
  object.expects(:expected_method).twice
  object.expected_method
  object.expected_method
  object.expected_method # => unexpected invocation

  object = mock()
  object.expects(:expected_method).twice
  object.expected_method
  # => verify fails

@private

Constrains the expectation to occur only when the state_machine is in the state specified by state_name.

@param [StateMachine::StatePredicate] state_machine.is(state_name) provides a mechanism to determine whether the state_machine is in the state specified by state_name when the expected method is invoked. @return [Expectation] the same expectation, thereby allowing invocations of other {Expectation} methods to be chained.

@see API#states @see StateMachine @see then

@example Using {when} to only allow invocation of methods when "power" state machine is in the "on" state.

  power = states('power').starts_as('off')

  radio = mock('radio')
  radio.expects(:switch_on).then(power.is('on'))
  radio.expects(:select_channel).with('BBC Radio 4').when(power.is('on'))
  radio.expects(:adjust_volume).with(+5).when(power.is('on'))
  radio.expects(:select_channel).with('BBC World Service').when(power.is('on'))
  radio.expects(:adjust_volume).with(-5).when(power.is('on'))
  radio.expects(:switch_off).then(power.is('off'))

Modifies expectation so that the expected method must be called with expected_parameters.

May be used with parameter matchers in {ParameterMatchers}.

@param [*Array] expected_parameters parameters expected. @yield optional block specifying custom matching. @yieldparam [*Array] actual_parameters parameters with which expected method was invoked. @yieldreturn [Boolean] true if actual_parameters are acceptable. @return [Expectation] the same expectation, thereby allowing invocations of other {Expectation} methods to be chained.

@example Expected method must be called with expected parameters.

  object = mock()
  object.expects(:expected_method).with(:param1, :param2)
  object.expected_method(:param1, :param2)
  # => verify succeeds

  object = mock()
  object.expects(:expected_method).with(:param1, :param2)
  object.expected_method(:param3)
  # => verify fails

@example Expected method must be called with a value divisible by 4.

  object = mock()
  object.expects(:expected_method).with() { |value| value % 4 == 0 }
  object.expected_method(16)
  # => verify succeeds

  object = mock()
  object.expects(:expected_method).with() { |value| value % 4 == 0 }
  object.expected_method(17)
  # => verify fails

Modifies expectation so that when the expected method is called, it yields with the specified parameters.

May be called multiple times on the same expectation for consecutive invocations.

@param [*Array] parameters parameters to be yielded. @return [Expectation] the same expectation, thereby allowing invocations of other {Expectation} methods to be chained. @see then

@example Yield parameters when expected method is invoked.

  object = mock()
  object.expects(:expected_method).yields('result')
  yielded_value = nil
  object.expected_method { |value| yielded_value = value }
  yielded_value # => 'result'

@example Yield different parameters on different invocations of the expected method.

  object = mock()
  object.stubs(:expected_method).yields(1).then.yields(2)
  yielded_values_from_first_invocation = []
  yielded_values_from_second_invocation = []
  object.expected_method { |value| yielded_values_from_first_invocation << value } # first invocation
  object.expected_method { |value| yielded_values_from_second_invocation << value } # second invocation
  yielded_values_from_first_invocation # => [1]
  yielded_values_from_second_invocation # => [2]

[Validate]