Module: RSpec::Core::Subject::ExampleGroupMethods

Included in:
ExampleGroup
Defined in:
lib/rspec/core/subject.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#explicit_subject_block ⇒ Object (readonly)

Returns the value of attribute explicit_subject_block.



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# File 'lib/rspec/core/subject.rb', line 204

def explicit_subject_block
  @explicit_subject_block
end

Instance Method Details

#its(attribute, &block) ⇒ Object

Creates a nested example group named by the submitted attribute, and then generates an example using the submitted block.

The attribute can be a Symbol or a String. Given a String with dots, the result is as though you concatenated that String onto the subject in an expression.

When the subject is a Hash, you can refer to the Hash keys by specifying a Symbol or String in an array.

Examples:


# This ...
describe Array do
  its(:size) { should eq(0) }
end

# ... generates the same runtime structure as this:
describe Array do
  describe "size" do
    it "should eq(0)" do
      subject.size.should eq(0)
    end
  end
end

describe Person do
  subject do
    Person.new.tap do |person|
      person.phone_numbers << "555-1212"
    end
  end

  its("phone_numbers.first") { should eq("555-1212") }
end

describe "a configuration Hash" do
  subject do
    { :max_users => 3,
      'admin' => :all_permissions }
  end

  its([:max_users]) { should eq(3) }
  its(['admin']) { should eq(:all_permissions) }

  # You can still access to its regular methods this way:
  its(:keys) { should include(:max_users) }
  its(:count) { should eq(2) }
end


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# File 'lib/rspec/core/subject.rb', line 148

def its(attribute, &block)
  describe(attribute) do
    example do
      self.class.class_eval do
        define_method(:subject) do
          if defined?(@_subject)
            @_subject
          else
            @_subject = Array === attribute ? super()[*attribute] : _nested_attribute(super(), attribute)
          end
        end
      end
      instance_eval(&block)
    end
  end
end

#subject(name = nil, &block) ⇒ Object

Declares a subject for an example group which can then be the implicit receiver (through delegation) of calls to should.

Given a name, defines a method with that name which returns the subject. This lets you declare the subject once and access it implicitly in one-liners and explicitly using an intention revealing name.

Examples:


describe CheckingAccount, "with $50" do
  subject { CheckingAccount.new(Money.new(50, :USD)) }
  it { should have_a_balance_of(Money.new(50, :USD)) }
  it { should_not be_overdrawn }
end

describe CheckingAccount, "with a non-zero starting balance" do
  subject(:account) { CheckingAccount.new(Money.new(50, :USD)) }
  it { should_not be_overdrawn }
  it "has a balance equal to the starting balance" do
    .balance.should eq(Money.new(50, :USD))
  end
end

Parameters:

  • name (String, Symbol) (defaults to: nil) —

    used to define an accessor with an intention revealing name

  • block —

    defines the value to be returned by subject in examples

See Also:



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# File 'lib/rspec/core/subject.rb', line 195

def subject(name=nil, &block)
  if name
    let(name, &block)
    subject { send name }
  else
    block ? @explicit_subject_block = block : explicit_subject || implicit_subject
  end
end