Example of a negated matcher

negated_matcher_spec.rb

require "rails_helper"

RSpec::Matchers.define_negated_matcher :not_be_present, :be_present

RSpec.describe "all matcher" do
  it "cooperates with negated matchers" do
    expect([nil, "", " "]).to all(not_be_present)

    # Whereas this doesn't work:
    # expect([nil, "", " "]).to_not all(be_present)
  end
end