Module: RSpec::Matchers

### Home Classes Methods

### In Files

- lib/rspec/matchers.rb
- lib/rspec/matchers/aliased_matcher.rb
- lib/rspec/matchers/built_in.rb
- lib/rspec/matchers/built_in/all.rb
- lib/rspec/matchers/built_in/base_matcher.rb
- lib/rspec/matchers/built_in/be.rb
- lib/rspec/matchers/built_in/be_between.rb
- lib/rspec/matchers/built_in/be_instance_of.rb
- lib/rspec/matchers/built_in/be_kind_of.rb
- lib/rspec/matchers/built_in/be_within.rb
- lib/rspec/matchers/built_in/change.rb
- lib/rspec/matchers/built_in/compound.rb
- lib/rspec/matchers/built_in/contain_exactly.rb
- lib/rspec/matchers/built_in/cover.rb
- lib/rspec/matchers/built_in/eq.rb
- lib/rspec/matchers/built_in/eql.rb
- lib/rspec/matchers/built_in/equal.rb
- lib/rspec/matchers/built_in/exist.rb
- lib/rspec/matchers/built_in/has.rb
- lib/rspec/matchers/built_in/have_attributes.rb
- lib/rspec/matchers/built_in/include.rb
- lib/rspec/matchers/built_in/match.rb
- lib/rspec/matchers/built_in/operators.rb
- lib/rspec/matchers/built_in/output.rb
- lib/rspec/matchers/built_in/raise_error.rb
- lib/rspec/matchers/built_in/satisfy.rb
- lib/rspec/matchers/built_in/respond_to.rb
- lib/rspec/matchers/built_in/start_or_end_with.rb
- lib/rspec/matchers/built_in/throw_symbol.rb
- lib/rspec/matchers/built_in/yield.rb
- lib/rspec/matchers/composable.rb
- lib/rspec/matchers/dsl.rb
- lib/rspec/matchers/expecteds_for_multiple_diffs.rb
- lib/rspec/matchers/generated_descriptions.rb
- lib/rspec/matchers/matcher_delegator.rb
- lib/rspec/matchers/matcher_protocol.rb
- lib/rspec/matchers/pretty.rb

### Namespace

- MODULE RSpec::Matchers::BuiltIn
- MODULE RSpec::Matchers::Composable
- MODULE RSpec::Matchers::DSL
- MODULE RSpec::Matchers::Pretty
- CLASS RSpec::Matchers::AliasedMatcher
- CLASS RSpec::Matchers::AliasedMatcherWithOperatorSupport
- CLASS RSpec::Matchers::AliasedNegatedMatcher
- CLASS RSpec::Matchers::ExpectedsForMultipleDiffs
- CLASS RSpec::Matchers::MatcherDelegator
- CLASS RSpec::Matchers::MatcherProtocol

### Methods

- ::alias_matcher
- ::clear_generated_description
- ::configuration
- ::define_negated_matcher
- ::generated_description
- #all
- #be
- #be_a
- #be_a_kind_of
- #be_an
- #be_an_instance_of
- #be_between
- #be_falsey
- #be_instance_of
- #be_kind_of
- #be_nil
- #be_truthy
- #be_within
- #change
- #contain_exactly
- #cover
- #end_with
- #eq
- #eql
- #equal
- #exist
- #have_attributes
- #include
- #match
- #match_array
- #output
- #raise_error
- #raise_exception
- #respond_to
- #satisfy
- #start_with
- #throw_symbol
- #yield_control
- #yield_successive_args
- #yield_with_args
- #yield_with_no_args

### Class/Module Index

Quicksearch

- RSpec
- RSpec::Expectations
- RSpec::Expectations::BlockExpectationTarget
- RSpec::Expectations::Configuration
- RSpec::Expectations::ExpectationHelper
- RSpec::Expectations::ExpectationNotMetError
- RSpec::Expectations::ExpectationTarget
- RSpec::Expectations::LegacyMacherAdapter
- RSpec::Expectations::LegacyMatcherAdapter
- RSpec::Expectations::LegacyMatcherAdapter::RSpec1
- RSpec::Expectations::LegacyMatcherAdapter::RSpec2
- RSpec::Expectations::NegativeExpectationHandler
- RSpec::Expectations::PositiveExpectationHandler
- RSpec::Expectations::Syntax
- RSpec::Expectations::Version
- RSpec::Matchers
- RSpec::Matchers::AliasedMatcher
- RSpec::Matchers::AliasedMatcherWithOperatorSupport
- RSpec::Matchers::AliasedNegatedMatcher
- RSpec::Matchers::BuiltIn
- RSpec::Matchers::BuiltIn::All
- RSpec::Matchers::BuiltIn::BaseMatcher
- RSpec::Matchers::BuiltIn::BaseMatcher::DefaultFailureMessages
- RSpec::Matchers::BuiltIn::Be
- RSpec::Matchers::BuiltIn::BeAKindOf
- RSpec::Matchers::BuiltIn::BeAnInstanceOf
- RSpec::Matchers::BuiltIn::BeBetween
- RSpec::Matchers::BuiltIn::BeComparedTo
- RSpec::Matchers::BuiltIn::BeFalsey
- RSpec::Matchers::BuiltIn::BeHelpers
- RSpec::Matchers::BuiltIn::BeNil
- RSpec::Matchers::BuiltIn::BePredicate
- RSpec::Matchers::BuiltIn::BeTruthy
- RSpec::Matchers::BuiltIn::BeWithin
- RSpec::Matchers::BuiltIn::CaptureStderr
- RSpec::Matchers::BuiltIn::CaptureStdout
- RSpec::Matchers::BuiltIn::CaptureStreamToTempfile
- RSpec::Matchers::BuiltIn::Change
- RSpec::Matchers::BuiltIn::ChangeDetails
- RSpec::Matchers::BuiltIn::ChangeFromValue
- RSpec::Matchers::BuiltIn::ChangeRelatively
- RSpec::Matchers::BuiltIn::ChangeToValue
- RSpec::Matchers::BuiltIn::Compound
- RSpec::Matchers::BuiltIn::Compound::And
- RSpec::Matchers::BuiltIn::Compound::NestedEvaluator
- RSpec::Matchers::BuiltIn::Compound::Or
- RSpec::Matchers::BuiltIn::Compound::SequentialEvaluator
- RSpec::Matchers::BuiltIn::ContainExactly
- RSpec::Matchers::BuiltIn::ContainExactly::PairingsMaximizer
- RSpec::Matchers::BuiltIn::Cover
- RSpec::Matchers::BuiltIn::EndWith
- RSpec::Matchers::BuiltIn::Eq
- RSpec::Matchers::BuiltIn::Eql
- RSpec::Matchers::BuiltIn::Equal
- RSpec::Matchers::BuiltIn::Exist
- RSpec::Matchers::BuiltIn::Exist::ExistenceTest
- RSpec::Matchers::BuiltIn::Has
- RSpec::Matchers::BuiltIn::HaveAttributes
- RSpec::Matchers::BuiltIn::Include
- RSpec::Matchers::BuiltIn::Match
- RSpec::Matchers::BuiltIn::NegativeOperatorMatcher
- RSpec::Matchers::BuiltIn::NullCapture
- RSpec::Matchers::BuiltIn::OperatorMatcher
- RSpec::Matchers::BuiltIn::Output
- RSpec::Matchers::BuiltIn::PositiveOperatorMatcher
- RSpec::Matchers::BuiltIn::RaiseError
- RSpec::Matchers::BuiltIn::RespondTo
- RSpec::Matchers::BuiltIn::Satisfy
- RSpec::Matchers::BuiltIn::SpecificValuesChange
- RSpec::Matchers::BuiltIn::StartAndEndWith
- RSpec::Matchers::BuiltIn::StartOrEndWith
- RSpec::Matchers::BuiltIn::StartWith
- RSpec::Matchers::BuiltIn::ThrowSymbol
- RSpec::Matchers::BuiltIn::YieldControl
- RSpec::Matchers::BuiltIn::YieldProbe
- RSpec::Matchers::BuiltIn::YieldSuccessiveArgs
- RSpec::Matchers::BuiltIn::YieldWithArgs
- RSpec::Matchers::BuiltIn::YieldWithNoArgs
- RSpec::Matchers::Composable
- RSpec::Matchers::DSL
- RSpec::Matchers::DSL::DefaultImplementations
- RSpec::Matchers::DSL::Macros
- RSpec::Matchers::DSL::Macros::Deprecated
- RSpec::Matchers::DSL::Matcher
- RSpec::Matchers::ExpectedsForMultipleDiffs
- RSpec::Matchers::MatcherDelegator
- RSpec::Matchers::MatcherProtocol
- RSpec::Matchers::Pretty
- BasicObject
- Object

No matching classes.

# RSpec::Matchers

RSpec::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 addtion 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(Fixnum)        # => 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(Fixnum)   # => 3.instance_of?(Fixnum)  | 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)

## 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 `require`d 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 {RSpec::Matchers::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 {RSpec::Matchers.alias_matcher}.

### Constants

BE_PREDICATE_REGEX
HAS_REGEX

### Attributes

last_expectation_handler[RW]

@private

last_matcher[RW]

@private

### Public Class Methods

alias_matcher(new_name, old_name, options={}, &description_override) click to toggle source

Defines a matcher alias. The returned matcher's `description` will be overriden to reflect the phrasing of the new name, which will be used in failure messages when passed as an argument to another matcher in a composed matcher expression.

@param new_name [Symbol] the new name for the matcher @param old_name [Symbol] the original name for the matcher @param options [Hash] options for the aliased matcher @option options [Class] :klass the ruby class to use as the decorator. (Not normally used). @yield [String] optional block that, when given, is used to define the overriden

    logic. The yielded arg is the original description or failure message. If no
    block is provided, a default override is used based on the old and new names.

@example

    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"

@example

    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"

@!macro [attach] alias_matcher

    @!parse
      alias $1 $2

    # File lib/rspec/matchers.rb, line 244
    def self.alias_matcher(new_name, old_name, options={}, &description_override)
      description_override ||= lambda do |old_desc|
        old_desc.gsub(Pretty.split_words(old_name), Pretty.split_words(new_name))
      end
      klass = options.fetch(:klass) { AliasedMatcher }

      define_method(new_name) do |*args, &block|
        matcher = __send__(old_name, *args, &block)
        klass.new(matcher, description_override)
      end
    end

clear_generated_description() click to toggle source

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

    # File lib/rspec/matchers/generated_descriptions.rb, line 11
    def self.clear_generated_description
      self.last_matcher = nil
      self.last_expectation_handler = nil
    end

configuration() click to toggle source

Delegates to {RSpec::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. @return [RSpec::Expectations::Configuration] the configuration object

    # File lib/rspec/matchers.rb, line 910
    def self.configuration
      Expectations.configuration
    end

define_negated_matcher(negated_name, base_name, &description_override) click to toggle source

Defines a negated matcher. The returned matcher's `description` and `failure_message` will be overriden to reflect the phrasing of the new name, and the match logic will be based on the original matcher but negated.

@param negated_name [Symbol] the name for the negated matcher @param base_name [Symbol] the name of the original matcher that will be negated @yield [String] optional block that, when given, is used to define the overriden

    logic. The yielded arg is the original description or failure message. If no
    block is provided, a default override is used based on the old and new names.

@example

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

@note 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`.

    # File lib/rspec/matchers.rb, line 276
    def self.define_negated_matcher(negated_name, base_name, &description_override)
      alias_matcher(negated_name, base_name, :klass => AliasedNegatedMatcher, &description_override)
    end

generated_description() click to toggle source

@api private Generates an an example description based on the last expectation. Used by rspec-core's one-liner syntax.

    # File 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

### Public Instance Methods

all(expected) click to toggle source

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

@example

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

@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.

@example

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

    # File lib/rspec/matchers.rb, line 629
    def all(expected)
      BuiltIn::All.new(expected)
    end

be(*args) click to toggle source

@example

    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)

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.

    # File lib/rspec/matchers.rb, line 320
    def be(*args)
      args.empty? ? Matchers::BuiltIn::Be.new : equal(*args)
    end

be_a(klass) click to toggle source

passes if target.kind_of?(klass)

    # File lib/rspec/matchers.rb, line 326
    def be_a(klass)
      be_a_kind_of(klass)
    end

Also aliased as: be_an
be_a_kind_of(expected) click to toggle source

Passes if actual.kind_of?(expected)

@example

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

    # File lib/rspec/matchers.rb, line 349
    def be_a_kind_of(expected)
      BuiltIn::BeAKindOf.new(expected)
    end

Also aliased as: be_kind_of
be_an(klass) click to toggle source
Alias for: be_a
be_an_instance_of(expected) click to toggle source

Passes if actual.instance_of?(expected)

@example

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

    # File lib/rspec/matchers.rb, line 337
    def be_an_instance_of(expected)
      BuiltIn::BeAnInstanceOf.new(expected)
    end

Also aliased as: be_instance_of
be_between(min, max) click to toggle source

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.

@example

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

    # File lib/rspec/matchers.rb, line 366
    def be_between(min, max)
      BuiltIn::BeBetween.new(min, max)
    end

be_falsey() click to toggle source

Passes if actual is falsey (false or nil)

    # File lib/rspec/matchers.rb, line 287
    def be_falsey
      BuiltIn::BeFalsey.new
    end

be_instance_of(expected) click to toggle source
Alias for: be_an_instance_of
be_kind_of(expected) click to toggle source
Alias for: be_a_kind_of
be_nil() click to toggle source

Passes if actual is nil

    # File lib/rspec/matchers.rb, line 295
    def be_nil
      BuiltIn::BeNil.new
    end

be_truthy() click to toggle source

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

    # File lib/rspec/matchers.rb, line 281
    def be_truthy
      BuiltIn::BeTruthy.new
    end

be_within(delta) click to toggle source

Passes if actual == expected +/- delta

@example

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

    # File lib/rspec/matchers.rb, line 376
    def be_within(delta)
      BuiltIn::BeWithin.new(delta)
    end

change(receiver=nil, message=nil, &block) click to toggle source

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

@param [Object] receiver @param [Symbol] message the message to send the receiver

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`

@example

    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)

## Notes

Evaluates `receiver.message` or `block` before and after it evaluates the block passed to `expect`.

`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`.

    # File lib/rspec/matchers.rb, line 460
    def change(receiver=nil, message=nil, &block)
      BuiltIn::Change.new(receiver, message, &block)
    end

contain_exactly(*items) click to toggle source

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.

@note This is also available using the `=~` operator with `should`,

    but `=~` is not supported with `expect`.

@example

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

@see match_array

    # File lib/rspec/matchers.rb, line 478
    def contain_exactly(*items)
      BuiltIn::ContainExactly.new(items)
    end

cover(*values) click to toggle source

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.

@example

    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

### Warning | Ruby >= 1.9 only

    # File lib/rspec/matchers.rb, line 496
    def cover(*values)
      BuiltIn::Cover.new(*values)
    end

end_with(*expected) click to toggle source

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.

@example

    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

    # File lib/rspec/matchers.rb, line 511
    def end_with(*expected)
      BuiltIn::EndWith.new(*expected)
    end

eq(expected) click to toggle source

Passes if `actual == expected`.

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

@example

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

    # File lib/rspec/matchers.rb, line 526
    def eq(expected)
      BuiltIn::Eq.new(expected)
    end

eql(expected) click to toggle source

Passes if `actual.eql?(expected)`

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

@example

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

    # File lib/rspec/matchers.rb, line 540
    def eql(expected)
      BuiltIn::Eql.new(expected)
    end

equal(expected) click to toggle source

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

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

@example

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

    # File lib/rspec/matchers.rb, line 554
    def equal(expected)
      BuiltIn::Equal.new(expected)
    end

exist(*args) click to toggle source

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

@example

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

    # File lib/rspec/matchers.rb, line 564
    def exist(*args)
      BuiltIn::Exist.new(*args)
    end

have_attributes(expected) click to toggle source

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

@example

    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) )

@note It will fail if actual doesn't respond to any of the expected attributes.

@example

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

    # File lib/rspec/matchers.rb, line 584
    def have_attributes(expected)
      BuiltIn::HaveAttributes.new(expected)
    end

include(*expected) click to toggle source

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.

@example

    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)

    # File lib/rspec/matchers.rb, line 606
    def include(*expected)
      BuiltIn::Include.new(*expected)
    end

match(expected) click to toggle source

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.

@example

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

@example

    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(Fixnum)
        ),
        :c => { :d => (a_value < 3) }
      }
    )

@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 DSL was evaluated in 2.x,
    `match` could not be used there), but is no longer needed in 3.x.

    # File lib/rspec/matchers.rb, line 664
    def match(expected)
      BuiltIn::Match.new(expected)
    end

match_array(items) click to toggle source

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

@example

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

@see contain_exactly

    # File lib/rspec/matchers.rb, line 682
    def match_array(items)
      contain_exactly(*items)
    end

output(expected=nil) click to toggle source

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.

@example

    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

@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`.

    # File lib/rspec/matchers.rb, line 716
    def output(expected=nil)
      BuiltIn::Output.new(expected)
    end

raise_error(error=Exception, message=nil, &block) click to toggle source

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 messsage specified as a String, matches only if both match. With a named error and messsage specified as a Regexp, matches only if both match. Pass an optional block to perform extra verifications on the exception matched

@example

    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(PoorRiskDecisionError, "that was too risky")
    expect { do_something_risky }.to raise_error(PoorRiskDecisionError, /oo ri/)

    expect { do_something_risky }.not_to raise_error

    # File lib/rspec/matchers.rb, line 735
    def raise_error(error=Exception, message=nil, &block)
      BuiltIn::RaiseError.new(error, message, &block)
    end

Also aliased as: raise_exception
raise_exception(error=Exception, message=nil, &block) click to toggle source
Alias for: raise_error
respond_to(*names) click to toggle source

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

@example

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

    # File lib/rspec/matchers.rb, line 754
    def respond_to(*names)
      BuiltIn::RespondTo.new(*names)
    end

satisfy(&block) click to toggle source

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.

@example

    expect(5).to satisfy { |n| n > 3 }

    # File lib/rspec/matchers.rb, line 772
    def satisfy(&block)
      BuiltIn::Satisfy.new(&block)
    end

start_with(*expected) click to toggle source

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.

@example

    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

    # File lib/rspec/matchers.rb, line 787
    def start_with(*expected)
      BuiltIn::StartWith.new(*expected)
    end

throw_symbol(expected_symbol=nil, expected_arg=nil) click to toggle source

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.

@example

    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')

    # File lib/rspec/matchers.rb, line 809
    def throw_symbol(expected_symbol=nil, expected_arg=nil)
      BuiltIn::ThrowSymbol.new(expected_symbol, expected_arg)
    end

yield_control() click to toggle source

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

@example

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

@note Your expect block must accept a parameter and pass it on to

    the method-under-test as a block.

    # File lib/rspec/matchers.rb, line 830
    def yield_control
      BuiltIn::YieldControl.new
    end

yield_successive_args(*args) click to toggle source

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.

@example

    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)

@note Your expect block must accept a parameter and pass it on to

    the method-under-test as a block.

    # File lib/rspec/matchers.rb, line 899
    def yield_successive_args(*args)
      BuiltIn::YieldSuccessiveArgs.new(*args)
    end

yield_with_args(*args) click to toggle source

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.

@example

    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(Fixnum) # because Fixnum === 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)

@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.

    # File lib/rspec/matchers.rb, line 878
    def yield_with_args(*args)
      BuiltIn::YieldWithArgs.new(*args)
    end

yield_with_no_args() click to toggle source

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

@example

    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

@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.

    # File lib/rspec/matchers.rb, line 848
    def yield_with_no_args
      BuiltIn::YieldWithNoArgs.new
    end

[Validate]

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