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Module: RSpec::Matchers

Relationships & Source Files
Namespace Children
Modules:
BuiltIn, Composable, DSL, EnglishPhrasing, FailMatchers
Classes:
AliasedMatcher, AliasedMatcherWithOperatorSupport, AliasedNegatedMatcher, BaseDelegator, MatcherDelegator, MatcherProtocol, MultiMatcherDiff
Extension / Inclusion / Inheritance Descendants
Included In:
Matchers::DSL::Matcher
Super Chains via Extension / Inclusion / Inheritance
Class Chain:
self, DSL
Defined in: rspec-expectations/lib/rspec/matchers.rb,
rspec-expectations/lib/rspec/matchers/aliased_matcher.rb,
rspec-expectations/lib/rspec/matchers/built_in.rb,
rspec-expectations/lib/rspec/matchers/composable.rb,
rspec-expectations/lib/rspec/matchers/dsl.rb,
rspec-expectations/lib/rspec/matchers/english_phrasing.rb,
rspec-expectations/lib/rspec/matchers/fail_matchers.rb,
rspec-expectations/lib/rspec/matchers/generated_descriptions.rb,
rspec-expectations/lib/rspec/matchers/matcher_delegator.rb,
rspec-expectations/lib/rspec/matchers/matcher_protocol.rb,
rspec-expectations/lib/rspec/matchers/multi_matcher_diff.rb,
rspec-expectations/lib/rspec/matchers/built_in/all.rb,
rspec-expectations/lib/rspec/matchers/built_in/base_matcher.rb,
rspec-expectations/lib/rspec/matchers/built_in/be.rb,
rspec-expectations/lib/rspec/matchers/built_in/be_between.rb,
rspec-expectations/lib/rspec/matchers/built_in/be_instance_of.rb,
rspec-expectations/lib/rspec/matchers/built_in/be_kind_of.rb,
rspec-expectations/lib/rspec/matchers/built_in/be_within.rb,
rspec-expectations/lib/rspec/matchers/built_in/change.rb,
rspec-expectations/lib/rspec/matchers/built_in/compound.rb,
rspec-expectations/lib/rspec/matchers/built_in/contain_exactly.rb,
rspec-expectations/lib/rspec/matchers/built_in/count_expectation.rb,
rspec-expectations/lib/rspec/matchers/built_in/cover.rb,
rspec-expectations/lib/rspec/matchers/built_in/eq.rb,
rspec-expectations/lib/rspec/matchers/built_in/eql.rb,
rspec-expectations/lib/rspec/matchers/built_in/equal.rb,
rspec-expectations/lib/rspec/matchers/built_in/exist.rb,
rspec-expectations/lib/rspec/matchers/built_in/has.rb,
rspec-expectations/lib/rspec/matchers/built_in/have_attributes.rb,
rspec-expectations/lib/rspec/matchers/built_in/include.rb,
rspec-expectations/lib/rspec/matchers/built_in/match.rb,
rspec-expectations/lib/rspec/matchers/built_in/operators.rb,
rspec-expectations/lib/rspec/matchers/built_in/output.rb,
rspec-expectations/lib/rspec/matchers/built_in/raise_error.rb,
rspec-expectations/lib/rspec/matchers/built_in/respond_to.rb,
rspec-expectations/lib/rspec/matchers/built_in/satisfy.rb,
rspec-expectations/lib/rspec/matchers/built_in/start_or_end_with.rb,
rspec-expectations/lib/rspec/matchers/built_in/throw_symbol.rb,
rspec-expectations/lib/rspec/matchers/built_in/yield.rb

Overview

Matchers provides a number of useful matchers we use to define expectations. Any object that implements the [matcher protocol](Matchers/MatcherProtocol) can be used as a matcher.

Predicates

In addition to matchers that are defined explicitly, ::RSpec will create custom matchers on the fly for any arbitrary predicate, giving your specs a much more natural language feel.

A Ruby predicate is a method that ends with a “?” and returns true or false. Common examples are ‘empty?`, nil?, and instance_of?.

All you need to do is write ‘expect(..).to be_` followed by the predicate without the question mark, and ::RSpec will figure it out from there. For example:

expect([]).to be_empty     # => [].empty?() | passes
expect([]).not_to be_empty # => [].empty?() | fails

In addition to prefixing the predicate matchers with “be_”, you can also use “be_a_” and “be_an_”, making your specs read much more naturally:

expect("a string").to be_an_instance_of(String) # =>"a string".instance_of?(String) # passes

expect(3).to be_a_kind_of(Integer)          # => 3.kind_of?(Numeric)     | passes
expect(3).to be_a_kind_of(Numeric)          # => 3.kind_of?(Numeric)     | passes
expect(3).to be_an_instance_of(Integer)     # => 3.instance_of?(Integer) | passes
expect(3).not_to be_an_instance_of(Numeric) # => 3.instance_of?(Numeric) | fails

::RSpec will also create custom matchers for predicates like ‘has_key?`. To use this feature, just state that the object should have_key(:key) and ::RSpec will call has_key?(:key) on the target. For example:

expect(:a => "A").to have_key(:a)
expect(:a => "A").to have_key(:b) # fails

You can use this feature to invoke any predicate that begins with “has_”, whether it is part of the Ruby libraries (like ‘Hash#has_key?`) or a method you wrote on your own class.

Note that ::RSpec does not provide composable aliases for these dynamic predicate matchers. You can easily define your own aliases, though:

RSpec::Matchers.alias_matcher :a_user_who_is_an_admin, :be_an_admin
expect(user_list).to include(a_user_who_is_an_admin)

Alias Matchers

With .alias_matcher, you can easily create an alternate name for a given matcher.

The description will also change according to the new name:

RSpec::Matchers.alias_matcher :a_list_that_sums_to, :sum_to
sum_to(3).description # => "sum to 3"
a_list_that_sums_to(3).description # => "a list that sums to 3"

or you can specify a custom description like this:

RSpec::Matchers.alias_matcher :a_list_sorted_by, :be_sorted_by do |description|
  description.sub("be sorted by", "a list sorted by")
end

be_sorted_by(:age).description # => "be sorted by age"
a_list_sorted_by(:age).description # => "a list sorted by age"

Custom Matchers

When you find that none of the stock matchers provide a natural feeling expectation, you can very easily write your own using RSpec’s matcher DSL or writing one from scratch.

Matcher DSL

Imagine that you are writing a game in which players can be in various zones on a virtual board. To specify that bob should be in zone 4, you could say:

expect(bob.current_zone).to eql(Zone.new("4"))

But you might find it more expressive to say:

expect(bob).to be_in_zone("4")

and/or

expect(bob).not_to be_in_zone("3")

You can create such a matcher like so:

RSpec::Matchers.define :be_in_zone do |zone|
  match do |player|
    player.in_zone?(zone)
  end
end

This will generate a be_in_zone method that returns a matcher with logical default messages for failures. You can override the failure messages and the generated description as follows:

RSpec::Matchers.define :be_in_zone do |zone|
  match do |player|
    player.in_zone?(zone)
  end

  failure_message do |player|
    # generate and return the appropriate string.
  end

  failure_message_when_negated do |player|
    # generate and return the appropriate string.
  end

  description do
    # generate and return the appropriate string.
  end
end

Each of the message-generation methods has access to the block arguments passed to the create method (in this case, zone). The failure message methods (failure_message and failure_message_when_negated) are passed the actual value (the receiver of expect(..) or expect(..).not_to).

Custom Matcher from scratch

You could also write a custom matcher from scratch, as follows:

class BeInZone
  def initialize(expected)
    @expected = expected
  end

  def matches?(target)
    @target = target
    @target.current_zone.eql?(Zone.new(@expected))
  end

  def failure_message
    "expected #{@target.inspect} to be in Zone #{@expected}"
  end

  def failure_message_when_negated
    "expected #{@target.inspect} not to be in Zone #{@expected}"
  end
end

… and a method like this:

def be_in_zone(expected)
  BeInZone.new(expected)
end

And then expose the method to your specs. This is normally done by including the method and the class in a module, which is then included in your spec:

module CustomGameMatchers
  class BeInZone
    # ...
  end

  def be_in_zone(expected)
    # ...
  end
end

describe "Player behaviour" do
  include CustomGameMatchers
  # ...
end

or you can include in globally in a spec_helper.rb file required from your spec file(s):

RSpec::configure do |config|
  config.include(CustomGameMatchers)
end

Making custom matchers composable

RSpec’s built-in matchers are designed to be composed, in expressions like:

expect(["barn", 2.45]).to contain_exactly(
  a_value_within(0.1).of(2.5),
  a_string_starting_with("bar")
)

Custom matchers can easily participate in composed matcher expressions like these. Include Composable in your custom matcher to make it support being composed (matchers defined using the DSL have this included automatically). Within your matcher’s ‘matches?` method (or the #match block, if using the DSL), use `values_match?(expected, actual)` rather than `expected == actual`. Under the covers, values_match? is able to match arbitrary nested data structures containing a mix of both matchers and non-matcher objects. It uses === and == to perform the matching, considering the values to match if either returns true. The Composable mixin also provides some helper methods for surfacing the matcher descriptions within your matcher’s description or failure messages.

RSpec’s built-in matchers each have a number of aliases that rephrase the matcher from a verb phrase (such as ‘be_within`) to a noun phrase (such as #a_value_within), which reads better when the matcher is passed as an argument in a composed matcher expressions, and also uses the noun-phrase wording in the matcher’s ‘description`, for readable failure messages. You can alias your custom matchers in similar fashion using .alias_matcher.

Negated Matchers

Sometimes if you want to test for the opposite using a more descriptive name instead of using ‘not_to`, you can use .define_negated_matcher:

RSpec::Matchers.define_negated_matcher :exclude, :include
include(1, 2).description # => "include 1 and 2"
exclude(1, 2).description # => "exclude 1 and 2"

While the most obvious negated form may be to add a ‘not_` prefix, the failure messages you get with that form can be confusing (e.g. “expected [actual] to not [verb], but did not”). We’ve found it works best to find a more positive name for the negated form, such as ‘avoid_changing` rather than not_change.

Constant Summary

Class Attribute Summary

Class Method Summary

DSL - Extended

alias_matcher

Defines a matcher alias.
define

Defines a custom matcher.
define_negated_matcher

Defines a negated matcher.
matcher

Alias for DSL#define.
warn_about_block_args

:nocov:

Instance Method Summary

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(method, *args, &block) (private)

[ GitHub ] 

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 961



def method_missing(method, *args, &block)
  case method.to_s
  when BE_PREDICATE_REGEX
    BuiltIn::BePredicate.new(method, *args, &block)
  when HAS_REGEX
    BuiltIn::Has.new(method, *args, &block)
  else
    super
  end
end


  







Class Attribute Details



  

    .last_expectation_handler   (rw)
  

  

    This method is for internal use only.
  

  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers/generated_descriptions.rb', line 5



attr_accessor :last_matcher, :last_expectation_handler


  








  

    .last_matcher   (rw)
  

  

    This method is for internal use only.
  

  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers/generated_descriptions.rb', line 5



attr_accessor :last_matcher, :last_expectation_handler


  







Class Method Details



  

    .alias_matcher(new_name, old_name, options = {}, &description_override)  
  



  

    

Extended from DSL#alias_matcher.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 250



def self.alias_matcher(*args, &block)
  super(*args, &block)
end


  








  

    .append_features(mod)   (private)
  

  

    This method is for internal use only.
  



  

    

Note that ‘included` doesn’t work for this because it is triggered after ‘RSpec::Matchers` is an ancestor of the inclusion host, rather than before, like append_features. It’s important we check this before in order to find the cases where it was already previously included.


  





  


  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1021



def append_features(mod)
  return super if mod < self # `mod < self` indicates a re-inclusion.

  subclasses = ObjectSpace.each_object(Class).select { |c| c < mod && c < self }
  return super unless subclasses.any?

  subclasses.reject! { |s| subclasses.any? { |s2| s < s2 } } # Filter to the root ancestor.
  subclasses = subclasses.map { |s| "`#{s}`" }.join(", ")

  RSpec.warning "`#{self}` has been included in a superclass (`#{mod}`) " \
                "after previously being included in subclasses (#{subclasses}), " \
                "which can trigger infinite recursion from `super` due to an MRI 1.9 bug " \
                "(https://redmine.ruby-lang.org/issues/3351). To work around this, " \
                "either upgrade to MRI 2.0+, include a dup of the module (e.g. " \
                "`include #{self}.dup`), or find a way to include `#{self}` in `#{mod}` " \
                "before it is included in subclasses (#{subclasses}). See " \
                "https://github.com/rspec/rspec-expectations/issues/814 for more info"

  super
end


  








  

    .clear_generated_description  
  

  

    This method is for internal use only.
  



  

    

Used by rspec-core to clear the state used to generate descriptions after an example.


  





  


  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers/generated_descriptions.rb', line 11



def self.clear_generated_description
  self.last_matcher = nil
  self.last_expectation_handler = nil
end


  








  

    .configuration  ⇒ RSpec::Expectations::Configuration 
  



  

    

Delegates to Expectations.configuration. This is here because rspec-core’s ‘expect_with` option looks for a configuration method on the mixin (`RSpec::Matchers`) to yield to a block.


  





  
Returns:





  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 951



def self.configuration
  Expectations.configuration
end


  








  

    .define(name, &declarations)  
  



  

    

Extended from DSL#define.


  



  [ GitHub ]






  

    .define_negated_matcher(negated_name, base_name, &description_override)  
  



  

    

Extended from DSL#define_negated_matcher.


  



  [ GitHub ]






  

    .generated_description  
  

  

    This method is for internal use only.
  



  

    

Generates an an example description based on the last expectation. Used by rspec-core’s one-liner syntax.


  





  


  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers/generated_descriptions.rb', line 19



def self.generated_description
  return nil if last_expectation_handler.nil?
  "#{last_expectation_handler.verb} #{last_description}"
end


  








  

    .is_a_describable_matcher?(obj)  ⇒ Boolean  (private)
  

  

    This method is for internal use only.
  



  

    
  





  


  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1008



def self.is_a_describable_matcher?(obj)
  is_a_matcher?(obj) && obj.respond_to?(:description)
end


  








  

    .is_a_matcher?(obj)  ⇒ Boolean  (private)
  

  

    This method is for internal use only.
  



  

    
  





  


  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 988



def self.is_a_matcher?(obj)
  return true  if ::RSpec::Matchers::BuiltIn::BaseMatcher === obj
  begin
    return false if obj.respond_to?(:i_respond_to_everything_so_im_not_really_a_matcher)
  rescue NoMethodError
    # Some objects, like BasicObject, don't implemented standard
    # reflection methods.
    return false
  end
  return false unless obj.respond_to?(:matches?)

  obj.respond_to?(:failure_message) ||
  obj.respond_to?(:failure_message_for_should) # support legacy matchers
end


  








  

    .last_description  
  

  

    This method is for internal use only.
  

  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers/generated_descriptions.rb', line 25



def self.last_description
  last_matcher.respond_to?(:description) ? last_matcher.description : <<-MESSAGE
When you call a matcher in an example without a String, like this:

specify { expect(object).to matcher }

or this:

it { is_expected.to matcher }

RSpec expects the matcher to have a #description method. You should either
add a String to the example this matcher is being used in, or give it a
description method. Then you won't have to suffer this lengthy warning again.
MESSAGE
end


  







Instance Method Details



  

    #a_block_changing(receiver = nil, message = nil, &block)  
  



  

    

Alias for #change.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1



alias a_block_changing change


  








  

    #a_block_outputting(expected = nil)  
  



  

    

Alias for #output.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1



alias a_block_outputting output


  








  

    #a_block_raising(error = BuiltIn::RaiseError::UndefinedValue, message = nil, &block)  
  



  

    

Alias for #raise_error.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1



alias a_block_raising raise_error


  








  

    #a_block_throwing(expected_symbol = nil, expected_arg = nil)  
  



  

    

Alias for #throw_symbol.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1



alias a_block_throwing throw_symbol


  








  

    #a_block_yielding_control  
  



  

    

Alias for #yield_control.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1



alias a_block_yielding_control yield_control


  








  

    #a_block_yielding_successive_args(*args)  
  



  

    

Alias for #yield_successive_args.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1



alias a_block_yielding_successive_args yield_successive_args


  








  

    #a_block_yielding_with_args(*args)  
  



  

    

Alias for #yield_with_args.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1



alias a_block_yielding_with_args yield_with_args


  








  

    #a_block_yielding_with_no_args  
  



  

    

Alias for #yield_with_no_args.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1



alias a_block_yielding_with_no_args yield_with_no_args


  








  

    #a_collection_containing_exactly(*items)  
  



  

    

Alias for #contain_exactly.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1



alias a_collection_containing_exactly contain_exactly


  








  

    #a_collection_ending_with(*expected)  
  



  

    

Alias for #end_with.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1



alias a_collection_ending_with end_with


  








  

    #a_collection_including(*expected)  
  



  

    

Alias for #include.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1



alias a_collection_including include


  








  

    #a_collection_starting_with(*expected)  
  



  

    

Alias for #start_with.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1



alias a_collection_starting_with start_with


  








  

    #a_falsey_value  
  



  

    

Alias for #be_falsey.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1



alias a_falsey_value be_falsey


  








  

    #a_falsy_value  
  



  

    

Alias for #be_falsey.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1



alias a_falsy_value be_falsey


  








  

    #a_hash_including(*expected)  
  



  

    

Alias for #include.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1



alias a_hash_including include


  








  

    #a_kind_of(expected)  
  



  

    

Alias for #be_a_kind_of.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1



alias a_kind_of be_a_kind_of


  








  

    #a_nil_value  
  



  

    

Alias for #be_nil.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1



alias a_nil_value be_nil


  








  

    #a_range_covering(*values)  
  



  

    

Alias for #cover.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1



alias a_range_covering cover


  








  

    #a_string_ending_with(*expected)  
  



  

    

Alias for #end_with.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1



alias a_string_ending_with end_with


  








  

    #a_string_including(*expected)  
  



  

    

Alias for #include.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1



alias a_string_including include


  








  

    #a_string_matching(expected)  
  



  

    

Alias for #match.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1



alias a_string_matching match


  








  

    #a_string_starting_with(*expected)  
  



  

    

Alias for #start_with.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1



alias a_string_starting_with start_with


  








  

    #a_truthy_value  
  



  

    

Alias for #be_truthy.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1



alias a_truthy_value be_truthy


  








  

    #a_value(*args)  
  



  

    

Alias for #be.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1



alias a_value be


  








  

    #a_value_between(min, max)  
  



  

    

Alias for #be_between.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1



alias a_value_between be_between


  








  

    #a_value_within(delta)  
  



  

    

Alias for #be_within.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1



alias a_value_within be_within


  








  

    #aggregate_failures(label = nil, metadata = {}) { ... } 
  



  

    
  

    Note:
    


The implementation of this feature uses a thread-local variable, which means that if you have an expectation failure in another thread, it’ll abort like normal.



  




Allows multiple expectations in the provided block to fail, and then aggregates them into a single exception, rather than aborting on the first expectation failure like normal. This allows you to see all failures from an entire set of expectations without splitting each off into its own example (which may slow things down if the example setup is expensive).


  





    

    
Examples:

      
aggregate_failures("verifying response") do
  expect(response.status).to eq(200)
  expect(response.headers).to include("Content-Type" => "text/plain")
  expect(response.body).to include("Success")
end

  


Parameters:


    
  
  • 
    label
    (String)
    (defaults to: nil)
—    
    

    label for this aggregation block, which will be included in the aggregated exception message.
    

    
  
    • 
  
  • 
    metadata
    (Hash)
    (defaults to: {})
—    
    

    additional metadata about this failure aggregation block. If multiple expectations fail, it will be exposed from the Expectations::MultipleExpectationsNotMetError exception. Mostly intended for internal ::RSpec use but you can use it as well.
    

    
  
    • 



Yields:


    
  
  • 
    
    
    

    Block containing as many expectation as you want. The block is simply yielded to, so you can trust that anything that works outside the block should work within it.
    

    
  
    • 



Raises:





  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 305



def aggregate_failures(label=nil, metadata={}, &block)
  Expectations::FailureAggregator.new(label, metadata).aggregate(&block)
end


  








  

    #all(expected)  
  



  

    
  

    Note:
    


The negative form ‘not_to all` is not supported. Instead use `not_to include` or pass a negative form of a matcher as the argument (e.g. `all exclude(:foo)`).



  


  

    Note:
    


You can also use this with compound matchers as well.



  




Passes if the provided matcher passes when checked against all elements of the collection.


  





    

    
Examples:

      
expect([1, 3, 5]).to all be_odd
expect([1, 3, 6]).to all be_odd # fails

      
expect([1, 3, 5]).to all( be_odd.and be_an(Integer) )

  




  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 662



def all(expected)
  BuiltIn::All.new(expected)
end


  








  

    #an_array_matching(items)  
  



  

    

Alias for #match_array.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1



alias an_array_matching match_array


  








  

    #an_instance_of(expected)  
  



  

    

Alias for #be_an_instance_of.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1



alias an_instance_of be_an_instance_of


  








  

    #an_object_eq_to(expected)  
  



  

    

Alias for #eq.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1



alias an_object_eq_to eq


  








  

    #an_object_eql_to(expected)  
  



  

    

Alias for #eql.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1



alias an_object_eql_to eql


  








  

    #an_object_equal_to(expected)  
  



  

    

Alias for #equal.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1



alias an_object_equal_to equal


  








  

    #an_object_existing(*args)  
  



  

    

Alias for #exist.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1



alias an_object_existing exist


  








  

    #an_object_having_attributes(expected)  
  



  

    

Alias for #have_attributes.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1



alias an_object_having_attributes have_attributes


  








  

    #an_object_matching(expected)  
  



  

    

Alias for #match.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1



alias an_object_matching match


  








  

    #an_object_responding_to(*names)  
  



  

    

Alias for #respond_to.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1



alias an_object_responding_to respond_to


  








  

    #an_object_satisfying(description = nil, &block)  
  



  

    

Alias for #satisfy.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1



alias an_object_satisfying satisfy


  








  

    #be(*args)  
    Also known as: #a_value
  



  

    

Given true, false, or nil, will pass if actual value is true, false or nil (respectively). Given no args means the caller should satisfy an if condition (to be or not to be).



Predicates are any Ruby method that ends in a “?” and returns true or false.  Given be_ followed by arbitrary_predicate (without the “?”), ::RSpec will match convert that into a query against the target object.



The arbitrary_predicate feature will handle any predicate prefixed with “be_an_” (e.g. be_an_instance_of), “be_a_” (e.g. be_a_kind_of) or “be_” (e.g. be_empty), letting you choose the prefix that best suits the predicate.


  





    

    
Examples:

      
expect(actual).to     be_truthy
expect(actual).to     be_falsey
expect(actual).to     be_nil
expect(actual).to     be_[arbitrary_predicate](*args)
expect(actual).not_to be_nil
expect(actual).not_to be_[arbitrary_predicate](*args)

  




  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 349



def be(*args)
  args.empty? ? Matchers::BuiltIn::Be.new : equal(*args)
end


  








  

    #be_a(klass)  
    Also known as: #be_an
  



  

    

passes if target.kind_of?(klass)


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 355



def be_a(klass)
  be_a_kind_of(klass)
end


  








  

    #be_a_kind_of(expected)  
    Also known as: #be_kind_of, #a_kind_of
  



  

    

Passes if actual.kind_of?(expected)


  





    

    
Examples:

      
expect(5).to     be_a_kind_of(Integer)
expect(5).to     be_a_kind_of(Numeric)
expect(5).not_to be_a_kind_of(Float)

  




  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 378



def be_a_kind_of(expected)
  BuiltIn::BeAKindOf.new(expected)
end


  








  

    #be_an(klass)  
  



  

    

Alias for #be_a.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 358



alias_method :be_an, :be_a


  








  

    #be_an_instance_of(expected)  
    Also known as: #be_instance_of, #an_instance_of
  



  

    

Passes if actual.instance_of?(expected)


  





    

    
Examples:

      
expect(5).to     be_an_instance_of(Integer)
expect(5).not_to be_an_instance_of(Numeric)
expect(5).not_to be_an_instance_of(Float)

  




  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 366



def be_an_instance_of(expected)
  BuiltIn::BeAnInstanceOf.new(expected)
end


  








  

    #be_between(min, max)  
    Also known as: #a_value_between
  



  

    

Passes if actual.between?(min, max). Works with any Comparable object, including String, Symbol, Time, or Numeric (Fixnum, Bignum, Integer, Float, Complex, and Rational).



By default, ‘be_between` is inclusive (i.e. passes when given either the max or min value), but you can make it exclusive by chaining that off the matcher.


  





    

    
Examples:

      
expect(5).to      be_between(1, 10)
expect(11).not_to be_between(1, 10)
expect(10).not_to be_between(1, 10).exclusive

  




  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 395



def be_between(min, max)
  BuiltIn::BeBetween.new(min, max)
end


  








  

    #be_falsey  
    Also known as: #be_falsy, #a_falsey_value, #a_falsy_value
  



  

    

Passes if actual is falsey (false or nil)


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 316



def be_falsey
  BuiltIn::BeFalsey.new
end


  








  

    #be_falsy  
  



  

    

Alias for #be_falsey.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1



alias be_falsy be_falsey


  








  

    #be_instance_of(expected)  
  



  

    

Alias for #be_an_instance_of.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 369



alias_method :be_instance_of, :be_an_instance_of


  








  

    #be_kind_of(expected)  
  



  

    

Alias for #be_a_kind_of.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 381



alias_method :be_kind_of, :be_a_kind_of


  








  

    #be_nil  
    Also known as: #a_nil_value
  



  

    

Passes if actual is nil


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 324



def be_nil
  BuiltIn::BeNil.new
end


  








  

    #be_truthy  
    Also known as: #a_truthy_value
  



  

    

Passes if actual is truthy (anything but false or nil)


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 310



def be_truthy
  BuiltIn::BeTruthy.new
end


  








  

    #be_within(delta)  
    Also known as: #a_value_within, #within
  



  

    

Passes if actual == expected +/- delta


  





    

    
Examples:

      
expect(result).to     be_within(0.5).of(3.0)
expect(result).not_to be_within(0.5).of(3.0)

  




  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 405



def be_within(delta)
  BuiltIn::BeWithin.new(delta)
end


  








  

    #change(receiver = nil, message = nil, &block)  
    Also known as: #a_block_changing, #changing
  



  

    

Applied to a proc, specifies that its execution will cause some value to change.



You can either pass receiver and message, or a block, but not both.



When passing a block, it must use the ‘{ … }` format, not do/end, as `{ … }` binds to the change method, whereas do/end would errantly bind to the expect(..).to or expect(…).not_to method.



You can chain any of the following off of the end to specify details about the change:


  • 

    ‘from`
    

  • 

    ‘to`
    




or any one of:


  • 

    ‘by`
    

  • 

    ‘by_at_least`
    

  • 

    ‘by_at_most`
    




Notes



Evaluates ‘receiver.message` or block before and after it evaluates the block passed to #expect. If the value is the same object, its before/after hash value is used to see if it has changed. Therefore, your object needs to properly implement hash to work correctly with this matcher.



‘expect( … ).not_to change` supports the form that specifies from (which specifies what you expect the starting, unchanged value to be) but does not support forms with subsequent calls to by, by_at_least, by_at_most or to.


  





    

    
Examples:

      
expect {
  team.add_player(player)
}.to change(roster, :count)

expect {
  team.add_player(player)
}.to change(roster, :count).by(1)

expect {
  team.add_player(player)
}.to change(roster, :count).by_at_least(1)

expect {
  team.add_player(player)
}.to change(roster, :count).by_at_most(1)

string = "string"
expect {
  string.reverse!
}.to change { string }.from("string").to("gnirts")

string = "string"
expect {
  string
}.not_to change { string }.from("string")

expect {
  person.happy_birthday
}.to change(person, :birthday).from(32).to(33)

expect {
  employee.develop_great_new_social_networking_app
}.to change(employee, :title).from("Mail Clerk").to("CEO")

expect {
  doctor.leave_office
}.to change(doctor, :sign).from(/is in/).to(/is out/)

user = User.new(:type => "admin")
expect {
  user.symbolize_type
}.to change(user, :type).from(String).to(Symbol)

  


Parameters:


    
  
  • 
    receiver
    (Object)
    (defaults to: nil)
  
    • 
  
  • 
    message
    (Symbol)
    (defaults to: nil)
—    
    

    the message to send the receiver
    

    
  
    • 





  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 492



def change(receiver=nil, message=nil, &block)
  BuiltIn::Change.new(receiver, message, &block)
end


  








  

    #changing(receiver = nil, message = nil, &block)  
  



  

    

Alias for #change.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1



alias changing change


  








  

    #contain_exactly(*items)  
    Also known as: #a_collection_containing_exactly, #containing_exactly
  



  

    
  

    Note:
    


This is also available using the ‘=~` operator with should, but =~ is not supported with #expect.



  




Passes if actual contains all of the expected regardless of order. This works for collections. Pass in multiple args and it will only pass if all args are found in collection.


  





    

    
Examples:

      
expect([1, 2, 3]).to contain_exactly(1, 2, 3)
expect([1, 2, 3]).to contain_exactly(1, 3, 2)

  

  
See Also:

  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 510



def contain_exactly(*items)
  BuiltIn::ContainExactly.new(items)
end


  








  

    #containing_exactly(*items)  
  



  

    

Alias for #contain_exactly.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1



alias containing_exactly contain_exactly


  








  

    #cover(*values)  
    Also known as: #a_range_covering, #covering
  



  

    

Passes if actual covers expected. This works for Ranges. You can also pass in multiple args and it will only pass if all args are found in Range.



Warning:: Ruby >= 1.9 only


  





    

    
Examples:

      
expect(1..10).to     cover(5)
expect(1..10).to     cover(4, 6)
expect(1..10).to     cover(4, 6, 11) # fails
expect(1..10).not_to cover(11)
expect(1..10).not_to cover(5)        # fails

  




  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 528



def cover(*values)
  BuiltIn::Cover.new(*values)
end


  








  

    #covering(*values)  
  



  

    

Alias for #cover.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1



alias covering cover


  








  

    #end_with(*expected)  
    Also known as: #a_collection_ending_with, #a_string_ending_with, #ending_with
  



  

    

Matches if the actual value ends with the expected value(s). In the case of a string, matches against the last ‘expected.length` characters of the actual string. In the case of an array, matches against the last expected.length elements of the actual array.


  





    

    
Examples:

      
expect("this string").to   end_with "string"
expect([0, 1, 2, 3, 4]).to end_with 4
expect([0, 2, 3, 4, 4]).to end_with 3, 4

  




  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 543



def end_with(*expected)
  BuiltIn::EndWith.new(*expected)
end


  








  

    #ending_with(*expected)  
  



  

    

Alias for #end_with.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1



alias ending_with end_with


  








  

    #eq(expected)  
    Also known as: #an_object_eq_to, #eq_to
  



  

    

Passes if actual == expected.



See www.ruby-doc.org/core/classes/Object.html#M001057 for more information about equality in Ruby.


  





    

    
Examples:

      
expect(5).to     eq(5)
expect(5).not_to eq(3)

  




  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 558



def eq(expected)
  BuiltIn::Eq.new(expected)
end


  








  

    #eq_to(expected)  
  



  

    

Alias for #eq.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1



alias eq_to eq


  








  

    #eql(expected)  
    Also known as: #an_object_eql_to, #eql_to
  



  

    

Passes if ‘actual.eql?(expected)`



See www.ruby-doc.org/core/classes/Object.html#M001057 for more information about equality in Ruby.


  





    

    
Examples:

      
expect(5).to     eql(5)
expect(5).not_to eql(3)

  




  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 572



def eql(expected)
  BuiltIn::Eql.new(expected)
end


  








  

    #eql_to(expected)  
  



  

    

Alias for #eql.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1



alias eql_to eql


  








  

    #equal(expected)  
    Also known as: #an_object_equal_to, #equal_to
  



  

    

Passes if actual.equal?(expected) (object identity).



See www.ruby-doc.org/core/classes/Object.html#M001057 for more information about equality in Ruby.


  





    

    
Examples:

      
expect(5).to       equal(5)   # Integers are equal
expect("5").not_to equal("5") # Strings that look the same are not the same object

  




  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 586



def equal(expected)
  BuiltIn::Equal.new(expected)
end


  








  

    #equal_to(expected)  
  



  

    

Alias for #equal.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1



alias equal_to equal


  








  

    #exist(*args)  
    Also known as: #an_object_existing, #existing
  



  

    

Passes if ‘actual.exist?` or actual.exists?


  





    

    
Examples:

      
expect(File).to exist("path/to/file")

  




  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 596



def exist(*args)
  BuiltIn::Exist.new(*args)
end


  








  

    #existing(*args)  
  



  

    

Alias for #exist.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1



alias existing exist


  








  

    #expect  ⇒ Expectations::ExpectationTarget 
  



  

    

Supports ‘expect(actual).to matcher` syntax by wrapping actual in an ExpectationTarget.


  





    

    
Examples:

      
expect(actual).to eq(expected)
expect(actual).not_to eq(expected)

  

  
See Also:

  
    
      
  • Expectations::ExpectationTarget#to
    • 
          
  • Expectations::ExpectationTarget#not_to
    • 
      




  [ GitHub ]






  

    #have_attributes(expected)  
    Also known as: #an_object_having_attributes, #having_attributes
  



  

    
  

    Note:
    


It will fail if actual doesn’t respond to any of the expected attributes.



  




Passes if actual’s attribute values match the expected attributes hash. This works no matter how you define your attribute readers.


  





    

    
Examples:

      
Person = Struct.new(:name, :age)
person = Person.new("Bob", 32)

expect(person).to have_attributes(:name => "Bob", :age => 32)
expect(person).to have_attributes(:name => a_string_starting_with("B"), :age => (a_value > 30) )

      
expect(person).to have_attributes(:color => "red")

  




  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 616



def have_attributes(expected)
  BuiltIn::HaveAttributes.new(expected)
end


  








  

    #having_attributes(expected)  
  



  

    

Alias for #have_attributes.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1



alias having_attributes have_attributes


  








  

    #include(*expected)  
    Also known as: #a_collection_including, #a_string_including, #a_hash_including, #including
  



  

    

Passes if actual includes expected. This works for collections and Strings. You can also pass in multiple args and it will only pass if all args are found in collection.


  





    

    
Examples:

      
expect([1,2,3]).to      include(3)
expect([1,2,3]).to      include(2,3)
expect([1,2,3]).to      include(2,3,4) # fails
expect([1,2,3]).not_to  include(4)
expect("spread").to     include("read")
expect("spread").not_to include("red")
expect(:a => 1, :b => 2).to include(:a)
expect(:a => 1, :b => 2).to include(:a, :b)
expect(:a => 1, :b => 2).to include(:a => 1)
expect(:a => 1, :b => 2).to include(:b => 2, :a => 1)
expect(:a => 1, :b => 2).to include(:c) # fails
expect(:a => 1, :b => 2).not_to include(:a => 2)

  




  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 639



def include(*expected)
  BuiltIn::Include.new(*expected)
end


  








  

    #including(*expected)  
  



  

    

Alias for #include.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1



alias including include


  








  

    #match(expected)  
    Also known as: #match_regex, #an_object_matching, #a_string_matching, #matching
  



  

    
  

    Note:
    


The ‘match_regex` alias is deprecated and is not recommended for use. It was added in 2.12.1 to facilitate its use from within custom matchers (due to how the custom matcher Matchers::DSL was evaluated in 2.x, match could not be used there), but is no longer needed in 3.x.



  




Given a ‘Regexp` or String, passes if actual.match(pattern) Given an arbitrary nested data structure (e.g. arrays and hashes), matches if `expected === actual` || `actual == expected` for each pair of elements.


  





    

    
Examples:

      
expect(email).to match(/^([^\s]+)((?:[-a-z0-9]+\.)+[a-z]{2,})$/i)
expect(email).to match("@example.com")

      
hash = {
  :a => {
    :b => ["foo", 5],
    :c => { :d => 2.05 }
  }
}

expect(hash).to match(
  :a => {
    :b => a_collection_containing_exactly(
      a_string_starting_with("f"),
      an_instance_of(Integer)
    ),
    :c => { :d => (a_value < 3) }
  }
)

  




  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 697



def match(expected)
  BuiltIn::Match.new(expected)
end


  








  

    #match_array(items)  
    Also known as: #an_array_matching
  



  

    

An alternate form of ‘contain_exactly` that accepts the expected contents as a single array arg rather than splatted out as individual items.


  





    

    
Examples:

      
expect(results).to contain_exactly(1, 2)
# is identical to:
expect(results).to match_array([1, 2])

  

  
See Also:

  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 715



def match_array(items)
  contain_exactly(*items)
end


  








  

    #match_regex(expected)  
  



  

    

Alias for #match.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1



alias match_regex match


  








  

    #matching(expected)  
  



  

    

Alias for #match.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1



alias matching match


  








  

    #output(expected = nil)  
    Also known as: #a_block_outputting
  



  

    
  

    Note:
    


‘to_stdout` and to_stderr work by temporarily replacing $stdout or $stderr, so they’re not able to intercept stream output that explicitly uses ‘STDOUT`/`STDERR` or that uses a reference to `$stdout`/`$stderr` that was stored before the matcher was used.



  


  

    Note:
    


‘to_stdout_from_any_process` and to_stderr_from_any_process use Tempfiles, and are thus significantly (~30x) slower than to_stdout and to_stderr.



  




With no arg, passes if the block outputs ‘to_stdout` or to_stderr. With a string, passes if the block outputs that specific string to_stdout or to_stderr. With a regexp or matcher, passes if the block outputs a string to_stdout or to_stderr that matches.



To capture output from any spawned subprocess as well, use ‘to_stdout_from_any_process` or to_stderr_from_any_process. Output from any process that inherits the main process’s corresponding standard stream will be captured.


  





    

    
Examples:

      
expect { print 'foo' }.to output.to_stdout
expect { print 'foo' }.to output('foo').to_stdout
expect { print 'foo' }.to output(/foo/).to_stdout

expect { do_something }.to_not output.to_stdout

expect { warn('foo') }.to output.to_stderr
expect { warn('foo') }.to output('foo').to_stderr
expect { warn('foo') }.to output(/foo/).to_stderr

expect { do_something }.to_not output.to_stderr

expect { system('echo foo') }.to output("foo\n").to_stdout_from_any_process
expect { system('echo foo', out: :err) }.to output("foo\n").to_stderr_from_any_process

  




  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 752



def output(expected=nil)
  BuiltIn::Output.new(expected)
end


  








  

    #raise_error(error = BuiltIn::RaiseError::UndefinedValue, message = nil, &block)  
    Also known as: #raise_exception, #a_block_raising, #raising
  



  

    

With no args, matches if any error is raised. With a named error, matches only if that specific error is raised. With a named error and message specified as a String, matches only if both match. With a named error and message specified as a Regexp, matches only if both match. Pass an optional block to perform extra verifications on the exception matched


  





    

    
Examples:

      
expect { do_something_risky }.to raise_error
expect { do_something_risky }.to raise_error(PoorRiskDecisionError)
expect { do_something_risky }.to raise_error(PoorRiskDecisionError) { |error| expect(error.data).to eq 42 }
expect { do_something_risky }.to raise_error { |error| expect(error.data).to eq 42 }
expect { do_something_risky }.to raise_error(PoorRiskDecisionError, "that was too risky")
expect { do_something_risky }.to raise_error(PoorRiskDecisionError, /oo ri/)
expect { do_something_risky }.to raise_error("that was too risky")

expect { do_something_risky }.not_to raise_error

  




  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 773



def raise_error(error=BuiltIn::RaiseError::UndefinedValue, message=nil, &block)
  BuiltIn::RaiseError.new(error, message, &block)
end


  








  

    #raise_exception(error = BuiltIn::RaiseError::UndefinedValue, message = nil, &block)  
  



  

    

Alias for #raise_error.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 776



alias_method :raise_exception, :raise_error


  








  

    #raising(error = BuiltIn::RaiseError::UndefinedValue, message = nil, &block)  
  



  

    

Alias for #raise_error.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1



alias raising raise_error


  








  

    #respond_to(*names)  
    Also known as: #an_object_responding_to, #responding_to
  



  

    

Matches if the target object responds to all of the names provided. Names can be Strings or Symbols.


  





    

    
Examples:

      
expect("string").to respond_to(:length)

  




  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 792



def respond_to(*names)
  BuiltIn::RespondTo.new(*names)
end


  








  

    #respond_to?(method)  ⇒ Boolean 
  



  

    

:nocov:


  





  


  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 979



def respond_to?(method, *)
  method = method.to_s
  method =~ DYNAMIC_MATCHER_REGEX || super
end


  








  

    #respond_to_missing?(method)  ⇒ Boolean  (private)
  



  

    
  





  


  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 974



def respond_to_missing?(method, *)
  method =~ DYNAMIC_MATCHER_REGEX || super
end


  








  

    #responding_to(*names)  
  



  

    

Alias for #respond_to.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1



alias responding_to respond_to


  








  

    #satisfy(description = nil, &block)  
    Also known as: #an_object_satisfying, #satisfying
  



  

    

Passes if the submitted block returns true. Yields target to the block.



Generally speaking, this should be thought of as a last resort when you can’t find any other way to specify the behaviour you wish to specify.



If you do find yourself in such a situation, you could always write a custom matcher, which would likely make your specs more expressive.


  





    

    
Examples:

      
expect(5).to satisfy { |n| n > 3 }
expect(5).to satisfy("be greater than 3") { |n| n > 3 }

  


Parameters:


    
  
  • 
    description
    (String)
    (defaults to: nil)
—    
    

    optional description to be used for this matcher.
    

    
  
    • 





  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 813



def satisfy(description=nil, &block)
  BuiltIn::Satisfy.new(description, &block)
end


  








  

    #satisfying(description = nil, &block)  
  



  

    

Alias for #satisfy.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1



alias satisfying satisfy


  








  

    #start_with(*expected)  
    Also known as: #a_collection_starting_with, #a_string_starting_with, #starting_with
  



  

    

Matches if the actual value starts with the expected value(s). In the case of a string, matches against the first ‘expected.length` characters of the actual string. In the case of an array, matches against the first expected.length elements of the actual array.


  





    

    
Examples:

      
expect("this string").to   start_with "this s"
expect([0, 1, 2, 3, 4]).to start_with 0
expect([0, 2, 3, 4, 4]).to start_with 0, 1

  




  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 828



def start_with(*expected)
  BuiltIn::StartWith.new(*expected)
end


  








  

    #starting_with(*expected)  
  



  

    

Alias for #start_with.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1



alias starting_with start_with


  








  

    #throw_symbol(expected_symbol = nil, expected_arg = nil)  
    Also known as: #a_block_throwing, #throwing
  



  

    

Given no argument, matches if a proc throws any Symbol.



Given a Symbol, matches if the given proc throws the specified Symbol.



Given a Symbol and an arg, matches if the given proc throws the specified Symbol with the specified arg.


  





    

    
Examples:

      
expect { do_something_risky }.to throw_symbol
expect { do_something_risky }.to throw_symbol(:that_was_risky)
expect { do_something_risky }.to throw_symbol(:that_was_risky, 'culprit')

expect { do_something_risky }.not_to throw_symbol
expect { do_something_risky }.not_to throw_symbol(:that_was_risky)
expect { do_something_risky }.not_to throw_symbol(:that_was_risky, 'culprit')

  




  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 850



def throw_symbol(expected_symbol=nil, expected_arg=nil)
  BuiltIn::ThrowSymbol.new(expected_symbol, expected_arg)
end


  








  

    #throwing(expected_symbol = nil, expected_arg = nil)  
  



  

    

Alias for #throw_symbol.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1



alias throwing throw_symbol


  








  

    #within(delta)  
  



  

    

Alias for #be_within.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1



alias within be_within


  








  

    #yield_control  
    Also known as: #a_block_yielding_control, #yielding_control
  



  

    
  

    Note:
    


Your expect block must accept a parameter and pass it on to the method-under-test as a block.



  




Passes if the method called in the expect block yields, regardless of whether or not arguments are yielded.


  





    

    
Examples:

      
expect { |b| 5.tap(&b) }.to yield_control
expect { |b| "a".to_sym(&b) }.not_to yield_control

  




  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 871



def yield_control
  BuiltIn::YieldControl.new
end


  








  

    #yield_successive_args(*args)  
    Also known as: #a_block_yielding_successive_args, #yielding_successive_args
  



  

    
  

    Note:
    


Your expect block must accept a parameter and pass it on to the method-under-test as a block.



  




Designed for use with methods that repeatedly yield (such as iterators). Passes if the method called in the expect block yields multiple times with arguments matching those given.



Argument matching is done using ‘===` (the case match operator) and ==. If the expected and actual arguments match with either operator, the matcher will pass.


  





    

    
Examples:

      
expect { |b| [1, 2, 3].each(&b) }.to yield_successive_args(1, 2, 3)
expect { |b| { :a => 1, :b => 2 }.each(&b) }.to yield_successive_args([:a, 1], [:b, 2])
expect { |b| [1, 2, 3].each(&b) }.not_to yield_successive_args(1, 2)

  




  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 940



def yield_successive_args(*args)
  BuiltIn::YieldSuccessiveArgs.new(*args)
end


  








  

    #yield_with_args(*args)  
    Also known as: #a_block_yielding_with_args, #yielding_with_args
  



  

    
  

    Note:
    


Your expect block must accept a parameter and pass it on to the method-under-test as a block.



  


  

    Note:
    


This matcher is not designed for use with methods that yield multiple times.



  




Given no arguments, matches if the method called in the expect block yields with arguments (regardless of what they are or how many there are).



Given arguments, matches if the method called in the expect block yields with arguments that match the given arguments.



Argument matching is done using ‘===` (the case match operator) and ==. If the expected and actual arguments match with either operator, the matcher will pass.


  





    

    
Examples:

      
expect { |b| 5.tap(&b) }.to yield_with_args # because #tap yields an arg
expect { |b| 5.tap(&b) }.to yield_with_args(5) # because 5 == 5
expect { |b| 5.tap(&b) }.to yield_with_args(Integer) # because Integer === 5
expect { |b| File.open("f.txt", &b) }.to yield_with_args(/txt/) # because /txt/ === "f.txt"

expect { |b| User.transaction(&b) }.not_to yield_with_args # because it yields no args
expect { |b| 5.tap(&b) }.not_to yield_with_args(1, 2, 3)

  




  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 919



def yield_with_args(*args)
  BuiltIn::YieldWithArgs.new(*args)
end


  








  

    #yield_with_no_args  
    Also known as: #a_block_yielding_with_no_args, #yielding_with_no_args
  



  

    
  

    Note:
    


Your expect block must accept a parameter and pass it on to the method-under-test as a block.



  


  

    Note:
    


This matcher is not designed for use with methods that yield multiple times.



  




Passes if the method called in the expect block yields with no arguments. Fails if it does not yield, or yields with arguments.


  





    

    
Examples:

      
expect { |b| User.transaction(&b) }.to yield_with_no_args
expect { |b| 5.tap(&b) }.not_to yield_with_no_args # because it yields with `5`
expect { |b| "a".to_sym(&b) }.not_to yield_with_no_args # because it does not yield

  




  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 889



def yield_with_no_args
  BuiltIn::YieldWithNoArgs.new
end


  








  

    #yielding_control  
  



  

    

Alias for #yield_control.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1



alias yielding_control yield_control


  








  

    #yielding_successive_args(*args)  
  



  

    

Alias for #yield_successive_args.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1



alias yielding_successive_args yield_successive_args


  








  

    #yielding_with_args(*args)  
  



  

    

Alias for #yield_with_args.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1



alias yielding_with_args yield_with_args


  








  

    #yielding_with_no_args  
  



  

    

Alias for #yield_with_no_args.


  



  [ GitHub ]


  

  


# File 'rspec-expectations/lib/rspec/matchers.rb', line 1



alias yielding_with_no_args yield_with_no_args