Example signal handling test

signal_spec.rb

require "spec_helper"

class MyClass
  def self.run(command)
    Signal.trap("TERM") { trap_term }

    `#{command}`
  end

  def self.trap_term
    puts "terminated"
    exit 1
  end
end

RSpec.describe "testing signal handling" do
  it "allows you to ensure that the code was run" do
    output_reader, output_writer = IO.pipe

    pid = fork do
      $stdout = $stderr = output_writer
      MyClass.run("sleep 2")
    end

    Process.kill("TERM", pid)
    _, status = Process.waitpid2(pid)

    output_writer.close
    output = output_reader.read

    expect(status.success?).to eql(false) # because of exit 1, see Process::Status
    expect(output).to eql("terminated\n")

    output_reader.close
  end
end