class Band
  include Mongoid::Document
  field :name, type: Mongoid::StringifiedSymbol
  validates_uniqueness_of :name
  embeds_many :albums
end

class Album
  include Mongoid::Document
  field :name, type: Mongoid::StringifiedSymbol
  validates_uniqueness_of :name
  embedded_in :band
end

describe "Band with multiple albums with same name" do
  it "should be invalid" do
    band = Band.new
    band.albums.build(name: :foo)
    band.albums.build(name: :foo)
    expect(band.invalid?).to be true # not ok
  end
end

describe "Band with duplicate name" do
  it "should be invalid" do
    _band = Band.create(name: :foo)
    expect(Band.new(name: :foo).invalid?).to be true # ok
  end
end