module RSpec::SubjectAsLambda

SubjectAsLambda provides a convenient way of turning a regular subject into a proc

@author Mikael Henriksson <mikael@zoolutions.se>

Public Instance Methods

is_expected() click to toggle source
# File lib/rspec/subject_as_lambda.rb, line 116
def is_expected # rubocop:disable Lint/NestedMethodDefinition, Naming/PredicateName
  expect { __it_lambda_subject }
end
it!(*options, &block) click to toggle source

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

@example

# 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

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.

@example

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

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

@example

describe "a configuration Hash" do
  subject do
    { :max_users => 3,
      'admin' => :all_permissions.
      'john_doe' => {:permissions => [:read, :write]}}
  end

  its([:max_users]) { should eq(3) }
  its(['admin']) { should eq(:all_permissions) }
  its(['john_doe', :permissions]) { should eq([:read, :write]) }

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

With an implicit subject, `is_expected` can be used as an alternative to `should` (e.g. for one-liner use). An `are_expected` alias is also supplied.

@example

describe Array do
  its(:size) { is_expected.to eq(0) }
end

You can pass more than one argument on the `its` block to add some metadata to the generated example

@example

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

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

Note that this method does not modify `subject` in any way, so if you refer to `subject` in `let` or `before` blocks, you're still referring to the outer subject.

@example

describe Person do
  subject { Person.new }
  before { subject.age = 25 }
  its(:age) { should eq(25) }
end
# File lib/rspec/subject_as_lambda.rb, line 109
def it!(*options, &block)
  it_lambda_caller = caller.reject { |file_line| file_line =~ %r{/rspec/subject_as_lambda} }
  describe(nil, caller: it_lambda_caller) do
    let(:__it_lambda_subject) do
      subject
    end

    def is_expected # rubocop:disable Lint/NestedMethodDefinition, Naming/PredicateName
      expect { __it_lambda_subject }
    end
    alias_method :are_expected, :is_expected

    options << {} unless options.last.is_a?(Hash)
    options.last[:caller] = it_lambda_caller

    example(nil, *options, &block)
  end
end
Also aliased as: specify!
specify!(*options, &block)
Alias for: it!