In the spec file.rb

 let(:organisation_customer) do
  {
    notes: "hot shot lawyer" ,
    staff_member_uuid: staff_member.uuid,
    created_at: DateTime.now.to_s,
    email: customer.email,
    name: customer.name,
    uuid: "123456"
  }
end

it "assigns the params" do
  expect(subject.reload).to match_attributes(organisation_customer)
end

Rspec Attributes Matcher.rb

RSpec::Matchers.define :match_attributes do |params|
  match do |model|
    params.map do |attr, param|
      !model.respond_to?(attr) || model.try(attr) == param
    end.all?
  end
  failure_message do |model|
    message = "#{model.class} attributes not updated correctly: "
    params.each  do |attr, param|
      next unless model.respond_to?(attr)
      res = model.try(attr)
      message << "\n\t#{model.class}##{attr} should be \"#{param}\" but was \"#{res}\"" unless res == param
    end
    message
  end
end

This gives you a list of all the attributes the do not match up, with their expected results.