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Module: RSpec::Mocks::ExampleMethods

Relationships & Source Files
Namespace Children
Modules:
Extension / Inclusion / Inheritance Descendants
Included In:
Super Chains via Extension / Inclusion / Inheritance
Instance Chain:
Defined in: rspec-mocks/lib/rspec/mocks/example_methods.rb

Overview

Contains methods intended to be used from within code examples. Mix this in to your test context (such as a test framework base class) to use rspec-mocks with your test framework. If you’re using rspec-core, it’ll take care of doing this for you.

Class Method Summary

Instance Method Summary

ArgumentMatchers - Included

#a_kind_of
#an_instance_of
#any_args

Acts like an arg splat, matching any number of args at any point in an arg list.

#anything

Matches any argument at all.

#array_excluding

Matches an array that excludes the specified items.

#array_including

Matches an array that includes the specified items at least once.

#boolean

Matches a boolean value.

#duck_type

Matches if the actual argument responds to the specified messages.

#hash_excluding

Matches a hash that doesn’t include the specified key(s) or key/value.

#hash_including

Matches a hash that includes the specified key(s) or key/value pairs.

#hash_not_including
#instance_of

Matches if ‘arg.instance_of?(klass)`.

#kind_of

Matches if ‘arg.kind_of?(klass)`.

#no_args

Matches no arguments.

Class Method Details

.declare_double(type, *args)

This method is for internal use only.
[ GitHub ]

  
# File 'rspec-mocks/lib/rspec/mocks/example_methods.rb', line 423

def self.declare_double(type, *args)
  args << {} unless Hash === args.last
  type.new(*args)
end

.declare_verifying_double(type, ref, *args)

This method is for internal use only.
[ GitHub ]

  
# File 'rspec-mocks/lib/rspec/mocks/example_methods.rb', line 408

def self.declare_verifying_double(type, ref, *args)
  if RSpec::Mocks.configuration.verify_doubled_constant_names? &&
    !ref.defined?

    RSpec::Mocks.error_generator.raise_verifying_double_not_defined_error(ref)
  end

  RSpec::Mocks.configuration.verifying_double_callbacks.each do |block|
    block.call(ref)
  end

  declare_double(type, ref, *args)
end

.extended(object)

This method is for internal use only.
[ GitHub ]

  
# File 'rspec-mocks/lib/rspec/mocks/example_methods.rb', line 401

def self.extended(object)
  # This gets extended in so that if `RSpec::Matchers` is included in
  # `klass` later, its definition of `expect` will take precedence.
  object.extend ExpectHost unless object.respond_to?(:expect)
end

.included(klass)

This method is for internal use only.
[ GitHub ]

  
# File 'rspec-mocks/lib/rspec/mocks/example_methods.rb', line 392

def self.included(klass)
  klass.class_exec do
    # This gets mixed in so that if `RSpec::Matchers` is included in
    # `klass` later, its definition of `expect` will take precedence.
    include ExpectHost unless method_defined?(:expect)
  end
end

Instance Method Details

#allow

Note:

If you disable the ‘:expect` syntax this method will be undefined.

Used to wrap an object in preparation for stubbing a method on it.

Examples:

allow(dbl).to receive(:foo).with(5).and_return(:return_value)
[ GitHub ]

#allow_any_instance_of

Note:

This is only available when you have enabled the ‘expect` syntax.

Used to wrap a class in preparation for stubbing a method on instances of it.

Examples:

allow_any_instance_of(MyClass).to receive(:foo)
[ GitHub ]

#allow_message_expectations_on_nil

Disables warning messages about expectations being set on nil.

By default warning messages are issued when expectations are set on nil. This is to prevent false-positives and to catch potential bugs early on.

[ GitHub ]

  
# File 'rspec-mocks/lib/rspec/mocks/example_methods.rb', line 201

def allow_message_expectations_on_nil
  RSpec::Mocks.space.proxy_for(nil).warn_about_expectations = false
end

#class_double(doubled_class) ⇒ Object #class_double(doubled_class, name) ⇒ Object #class_double(doubled_class, stubs) ⇒ Object #class_double(doubled_class, name, stubs) ⇒ Object

Constructs a test double against a specific class. If the given class name has been loaded, only class methods defined on the class are allowed to be stubbed. In all other ways it behaves like a [double](double).

Overloads:

  • #class_double(doubled_class) ⇒ Object

    Parameters:

    • doubled_class (String, Module)
  • #class_double(doubled_class, name) ⇒ Object

    Parameters:

    • doubled_class (String, Module)
    • name (String/Symbol)

      name or description to be used in failure messages

  • #class_double(doubled_class, stubs) ⇒ Object

    Parameters:

    • doubled_class (String, Module)
    • stubs (Hash)

      hash of message/return-value pairs

  • #class_double(doubled_class, name, stubs) ⇒ Object

    Parameters:

    • doubled_class (String, Module)
    • name (String/Symbol)

      name or description to be used in failure messages

    • stubs (Hash)

      hash of message/return-value pairs

Returns:

[ GitHub ]

  
# File 'rspec-mocks/lib/rspec/mocks/example_methods.rb', line 79

def class_double(doubled_class, *args)
  ref = ObjectReference.for(doubled_class)
  ExampleMethods.declare_verifying_double(ClassVerifyingDouble, ref, *args)
end

#class_spy(doubled_class) ⇒ Object #class_spy(doubled_class, name) ⇒ Object #class_spy(doubled_class, stubs) ⇒ Object #class_spy(doubled_class, name, stubs) ⇒ Object

Constructs a test double that is optimized for use with ‘have_received` against a specific class. If the given class name has been loaded, only class methods defined on the class are allowed to be stubbed. With a normal double one has to stub methods in order to be able to spy them. An class_spy automatically spies on all class methods to which the class responds.

Overloads:

  • #class_spy(doubled_class) ⇒ Object

    Parameters:

    • doubled_class (String, Module)
  • #class_spy(doubled_class, name) ⇒ Object

    Parameters:

    • doubled_class (String, Class)
    • name (String/Symbol)

      name or description to be used in failure messages

  • #class_spy(doubled_class, stubs) ⇒ Object

    Parameters:

    • doubled_class (String, Module)
    • stubs (Hash)

      hash of message/return-value pairs

  • #class_spy(doubled_class, name, stubs) ⇒ Object

    Parameters:

    • doubled_class (String, Class)
    • name (String/Symbol)

      name or description to be used in failure messages

    • stubs (Hash)

      hash of message/return-value pairs

Returns:

[ GitHub ]

  
# File 'rspec-mocks/lib/rspec/mocks/example_methods.rb', line 191

def class_spy(*args)
  class_double(*args).as_null_object
end

#doubleDouble #double(name) ⇒ Double #double(stubs) ⇒ Double #double(name, stubs) ⇒ Double

Constructs an instance of [RSpec::Mocks::Double](RSpec::Mocks::Double) configured with an optional name, used for reporting in failure messages, and an optional hash of message/return-value pairs.

Examples:

book = double("book", :title => "The RSpec Book")
book.title #=> "The RSpec Book"

card = double("card", :suit => "Spades", :rank => "A")
card.suit  #=> "Spades"
card.rank  #=> "A"

Overloads:

  • #double(name) ⇒ Double

    Parameters:

    • name (String/Symbol)

      name or description to be used in failure messages

  • #double(stubs) ⇒ Double

    Parameters:

    • stubs (Hash)

      hash of message/return-value pairs

  • #double(name, stubs) ⇒ Double

    Parameters:

    • name (String/Symbol)

      name or description to be used in failure messages

    • stubs (Hash)

      hash of message/return-value pairs

[ GitHub ]

  
# File 'rspec-mocks/lib/rspec/mocks/example_methods.rb', line 34

def double(*args)
  ExampleMethods.declare_double(Double, *args)
end

#expect

Note:

This method is usually provided by rspec-expectations. However, if you use rspec-mocks without rspec-expectations, there’s a definition of it that is made available here. If you disable the ‘:expect` syntax this method will be undefined.

Used to wrap an object in preparation for setting a mock expectation on it.

Examples:

expect(obj).to receive(:foo).with(5).and_return(:return_value)
[ GitHub ]

#expect_any_instance_of

Note:

If you disable the ‘:expect` syntax this method will be undefined.

Used to wrap a class in preparation for setting a mock expectation on instances of it.

Examples:

expect_any_instance_of(MyClass).to receive(:foo)
[ GitHub ]

#have_received(method_name, &block)

Note:

‘have_received(…).with(…)` is unable to work properly when passed arguments are mutated after the spy records the received message.

Verifies that the given object received the expected message during the course of the test. On a spy objects or as null object doubles this works for any method, on other objects the method must have been stubbed beforehand in order for messages to be verified.

Stubbing and verifying messages received in this way implements the Test Spy pattern.

Examples:

invitation = double('invitation', accept: true)
user.accept_invitation(invitation)
expect(invitation).to have_received(:accept)

# You can also use most message expectations:
expect(invitation).to have_received(:accept).with(mailer).once

Parameters:

  • method_name (Symbol)

    name of the method expected to have been called.

[ GitHub ]

  
# File 'rspec-mocks/lib/rspec/mocks/example_methods.rb', line 281

def have_received(method_name, &block)
  Matchers::HaveReceived.new(method_name, &block)
end

#hide_const(constant_name)

Hides the named constant with the given value. The constant will be undefined for the duration of the test.

Like method stubs, the constant will be restored to its original value when the example completes.

Examples:

hide_const("MyClass") # => MyClass is now an undefined constant

Parameters:

  • constant_name (String)

    The fully qualified name of the constant. The current constant scoping at the point of call is not considered.

[ GitHub ]

  
# File 'rspec-mocks/lib/rspec/mocks/example_methods.rb', line 256

def hide_const(constant_name)
  ConstantMutator.hide(constant_name)
end

#instance_double(doubled_class) ⇒ Object #instance_double(doubled_class, name) ⇒ Object #instance_double(doubled_class, stubs) ⇒ Object #instance_double(doubled_class, name, stubs) ⇒ Object

Constructs a test double against a specific class. If the given class name has been loaded, only instance methods defined on the class are allowed to be stubbed. In all other ways it behaves like a [double](double).

Overloads:

  • #instance_double(doubled_class) ⇒ Object

    Parameters:

    • doubled_class (String, Class)
  • #instance_double(doubled_class, name) ⇒ Object

    Parameters:

    • doubled_class (String, Class)
    • name (String/Symbol)

      name or description to be used in failure messages

  • #instance_double(doubled_class, stubs) ⇒ Object

    Parameters:

    • doubled_class (String, Class)
    • stubs (Hash)

      hash of message/return-value pairs

  • #instance_double(doubled_class, name, stubs) ⇒ Object

    Parameters:

    • doubled_class (String, Class)
    • name (String/Symbol)

      name or description to be used in failure messages

    • stubs (Hash)

      hash of message/return-value pairs

Returns:

[ GitHub ]

  
# File 'rspec-mocks/lib/rspec/mocks/example_methods.rb', line 56

def instance_double(doubled_class, *args)
  ref = ObjectReference.for(doubled_class)
  ExampleMethods.declare_verifying_double(InstanceVerifyingDouble, ref, *args)
end

#instance_spy(doubled_class) ⇒ Object #instance_spy(doubled_class, name) ⇒ Object #instance_spy(doubled_class, stubs) ⇒ Object #instance_spy(doubled_class, name, stubs) ⇒ Object

Constructs a test double that is optimized for use with ‘have_received` against a specific class. If the given class name has been loaded, only instance methods defined on the class are allowed to be stubbed. With a normal double one has to stub methods in order to be able to spy them. An instance_spy automatically spies on all instance methods to which the class responds.

Overloads:

  • #instance_spy(doubled_class) ⇒ Object

    Parameters:

    • doubled_class (String, Class)
  • #instance_spy(doubled_class, name) ⇒ Object

    Parameters:

    • doubled_class (String, Class)
    • name (String/Symbol)

      name or description to be used in failure messages

  • #instance_spy(doubled_class, stubs) ⇒ Object

    Parameters:

    • doubled_class (String, Class)
    • stubs (Hash)

      hash of message/return-value pairs

  • #instance_spy(doubled_class, name, stubs) ⇒ Object

    Parameters:

    • doubled_class (String, Class)
    • name (String/Symbol)

      name or description to be used in failure messages

    • stubs (Hash)

      hash of message/return-value pairs

Returns:

[ GitHub ]

  
# File 'rspec-mocks/lib/rspec/mocks/example_methods.rb', line 144

def instance_spy(*args)
  instance_double(*args).as_null_object
end

#object_double(object_or_name) ⇒ Object #object_double(object_or_name, name) ⇒ Object #object_double(object_or_name, stubs) ⇒ Object #object_double(object_or_name, name, stubs) ⇒ Object

Constructs a test double against a specific object. Only the methods the object responds to are allowed to be stubbed. If a String argument is provided, it is assumed to reference a constant object which is used for verification. In all other ways it behaves like a [double](double).

Overloads:

  • #object_double(object_or_name) ⇒ Object

    Parameters:

    • object_or_name (String, Object)
  • #object_double(object_or_name, name) ⇒ Object

    Parameters:

    • object_or_name (String, Object)
    • name (String/Symbol)

      name or description to be used in failure messages

  • #object_double(object_or_name, stubs) ⇒ Object

    Parameters:

    • object_or_name (String, Object)
    • stubs (Hash)

      hash of message/return-value pairs

  • #object_double(object_or_name, name, stubs) ⇒ Object

    Parameters:

    • object_or_name (String, Object)
    • name (String/Symbol)

      name or description to be used in failure messages

    • stubs (Hash)

      hash of message/return-value pairs

Returns:

[ GitHub ]

  
# File 'rspec-mocks/lib/rspec/mocks/example_methods.rb', line 102

def object_double(object_or_name, *args)
  ref = ObjectReference.for(object_or_name, :allow_direct_object_refs)
  ExampleMethods.declare_verifying_double(ObjectVerifyingDouble, ref, *args)
end

#object_spy(object_or_name) ⇒ Object #object_spy(object_or_name, name) ⇒ Object #object_spy(object_or_name, stubs) ⇒ Object #object_spy(object_or_name, name, stubs) ⇒ Object

Constructs a test double that is optimized for use with ‘have_received` against a specific object. Only instance methods defined on the object are allowed to be stubbed. With a normal double one has to stub methods in order to be able to spy them. An object_spy automatically spies on all methods to which the object responds.

Overloads:

  • #object_spy(object_or_name) ⇒ Object

    Parameters:

    • object_or_name (String, Object)
  • #object_spy(object_or_name, name) ⇒ Object

    Parameters:

    • object_or_name (String, Class)
    • name (String/Symbol)

      name or description to be used in failure messages

  • #object_spy(object_or_name, stubs) ⇒ Object

    Parameters:

    • object_or_name (String, Object)
    • stubs (Hash)

      hash of message/return-value pairs

  • #object_spy(object_or_name, name, stubs) ⇒ Object

    Parameters:

    • object_or_name (String, Class)
    • name (String/Symbol)

      name or description to be used in failure messages

    • stubs (Hash)

      hash of message/return-value pairs

Returns:

[ GitHub ]

  
# File 'rspec-mocks/lib/rspec/mocks/example_methods.rb', line 167

def object_spy(*args)
  object_double(*args).as_null_object
end

#receive

Note:

If you disable the ‘:expect` syntax this method will be undefined.

Used to specify a message that you expect or allow an object to receive. The object returned by ‘receive` supports the same fluent interface that #should_receive and #stub have always supported, allowing you to constrain the arguments or number of times, and configure how the object should respond to the message.

Examples:

expect(obj).to receive(:hello).with("world").exactly(3).times
[ GitHub ]

#receive_message_chain(method1, method2) #receive_message_chain("method1.method2") #receive_message_chain(method1, method_to_value_hash)

Note:

If you disable the ‘:expect` syntax this method will be undefined.

stubs/mocks a chain of messages on an object or test double.

## Warning:

Chains can be arbitrarily long, which makes it quite painless to violate the Law of Demeter in violent ways, so you should consider any use of ‘receive_message_chain` a code smell. Even though not all code smells indicate real problems (think fluent interfaces), receive_message_chain still results in brittle examples. For example, if you write `allow(foo).to receive_message_chain(:bar, :baz => 37)` in a spec and then the implementation calls foo.baz.bar, the stub will not work.

Examples:

allow(double).to receive_message_chain("foo.bar") { :baz }
allow(double).to receive_message_chain(:foo, :bar => :baz)
allow(double).to receive_message_chain(:foo, :bar) { :baz }

# Given any of ^^ these three forms ^^:
double.foo.bar # => :baz

# Common use in Rails/ActiveRecord:
allow(Article).to receive_message_chain("recent.published") { [Article.new] }
[ GitHub ]

#receive_messages

Note:

If you disable the ‘:expect` syntax this method will be undefined.

Shorthand syntax used to setup message(s), and their return value(s), that you expect or allow an object to receive. The method takes a hash of messages and their respective return values. Unlike with ‘receive`, you cannot apply further customizations using a block or the fluent interface.

Examples:

allow(obj).to receive_messages(:speak => "Hello World")
allow(obj).to receive_messages(:speak => "Hello", :meow => "Meow")
[ GitHub ]

#spyDouble #spy(name) ⇒ Double #spy(stubs) ⇒ Double #spy(name, stubs) ⇒ Double

Constructs a test double that is optimized for use with ‘have_received`. With a normal double one has to stub methods in order to be able to spy them. A spy automatically spies on all methods.

Overloads:

  • #spy(name) ⇒ Double

    Parameters:

    • name (String/Symbol)

      name or description to be used in failure messages

  • #spy(stubs) ⇒ Double

    Parameters:

    • stubs (Hash)

      hash of message/return-value pairs

  • #spy(name, stubs) ⇒ Double

    Parameters:

    • name (String/Symbol)

      name or description to be used in failure messages

    • stubs (Hash)

      hash of message/return-value pairs

[ GitHub ]

  
# File 'rspec-mocks/lib/rspec/mocks/example_methods.rb', line 120

def spy(*args)
  double(*args).as_null_object
end

#stub_const(constant_name, value, options = {}) ⇒ Object

Stubs the named constant with the given value. Like method stubs, the constant will be restored to its original value (or lack of one, if it was undefined) when the example completes.

Examples:

stub_const("MyClass", Class.new) # => Replaces (or defines) MyClass with a new class object.
stub_const("SomeModel::PER_PAGE", 5) # => Sets SomeModel::PER_PAGE to 5.

class CardDeck
  SUITS = [:Spades, :Diamonds, :Clubs, :Hearts]
  NUM_CARDS = 52
end

stub_const("CardDeck", Class.new)
CardDeck::SUITS # => uninitialized constant error
CardDeck::NUM_CARDS # => uninitialized constant error

stub_const("CardDeck", Class.new, :transfer_nested_constants => true)
CardDeck::SUITS # => our suits array
CardDeck::NUM_CARDS # => 52

stub_const("CardDeck", Class.new, :transfer_nested_constants => [:SUITS])
CardDeck::SUITS # => our suits array
CardDeck::NUM_CARDS # => uninitialized constant error

Parameters:

  • constant_name (String)

    The fully qualified name of the constant. The current constant scoping at the point of call is not considered.

  • value (Object)

    The value to make the constant refer to. When the example completes, the constant will be restored to its prior state.

  • options (Hash) (defaults to: {})

    Stubbing options.

Options Hash (options):

  • :transfer_nested_constants (Boolean, Array<Symbol>)

    Determines what nested constants, if any, will be transferred from the original value of the constant to the new value of the constant. This only works if both the original and new values are modules (or classes).

Returns:

  • (Object)

    the stubbed value of the constant

[ GitHub ]

  
# File 'rspec-mocks/lib/rspec/mocks/example_methods.rb', line 241

def stub_const(constant_name, value, options={})
  ConstantMutator.stub(constant_name, value, options)
end

#without_partial_double_verification

Turns off the verifying of partial doubles for the duration of the block, this is useful in situations where methods are defined at run time and you wish to define stubs for them but not turn off partial doubles for the entire run suite. (e.g. view specs in rspec-rails).

[ GitHub ]

  
# File 'rspec-mocks/lib/rspec/mocks/example_methods.rb', line 289

def without_partial_double_verification
  original_state = Mocks.configuration.temporarily_suppress_partial_double_verification
  Mocks.configuration.temporarily_suppress_partial_double_verification = true
  yield
ensure
  Mocks.configuration.temporarily_suppress_partial_double_verification = original_state
end