`have_attributes` matcher

Use the have_attributes matcher to specify that an object’s attributes match the expected attributes:

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

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

The matcher will fail if actual doesn’t respond to any of the expected attributes:

    expect(person).to have_attributes(:name => "Jim", :color => 'red')

Basic usage

Given a file named “basichaveattributesmatcherspec.rb” with:

Person = Struct.new(:name, :age)

RSpec.describe Person.new("Jim", 32) do
  it { is_expected.to have_attributes(:name => "Jim") }
  it { is_expected.to have_attributes(:name => a_string_starting_with("J") ) }
  it { is_expected.to have_attributes(:age => 32) }
  it { is_expected.to have_attributes(:age => (a_value > 30) ) }
  it { is_expected.to have_attributes(:name => "Jim", :age => 32) }
  it { is_expected.to have_attributes(:name => a_string_starting_with("J"), :age => (a_value > 30) ) }
  it { is_expected.not_to have_attributes(:name => "Bob") }
  it { is_expected.not_to have_attributes(:age => 10) }
  it { is_expected.not_to have_attributes(:age => (a_value < 30) ) }

  # deliberate failures
  it { is_expected.to have_attributes(:name => "Bob") }
  it { is_expected.to have_attributes(:age => 10) }

  # fails if any of the attributes don't match
  it { is_expected.to have_attributes(:name => "Bob", :age => 32) }
  it { is_expected.to have_attributes(:name => "Jim", :age => 10) }
  it { is_expected.to have_attributes(:name => "Bob", :age => 10) }
end

When I run rspec basic_have_attributes_matcher_spec.rb

Then the output should contain “14 examples, 5 failures”.