https://twitter.com/nateberkopec/status/1232315671985389568

inherit_test_setup.rb

class Test
  def run
    puts ">>> starting test run: #{self.class.name}"
    setup
    the_test_methods.each do |test_method|
      puts "running #{self.class.name}##{test_method}"
      send(test_method)
    end
  end

  def the_test_methods
    self.class.public_instance_methods.select {|meth| meth.to_s =~ /^test_.*$/ }
  end
end

def TestSetupFrom(test_klass)
  new_klass = Class.new(test_klass)
  new_klass
    .public_instance_methods
    .select {|meth| meth.to_s =~ /^test_.*$/ }
    .each {|test_meth| new_klass.undef_method(test_meth)}

  new_klass
end

class TestArray < Test
  def setup
    puts "parent setup"
  end

  def test_array
    p ([].kind_of?(Array)) ? true : false
  end
end

class TestSomething < TestSetupFrom(TestArray)
  def setup
    super
    puts "child setup"
  end

  def test_something
    p (1 == 1) ? true : false
  end
end

TestArray.new.run
TestSomething.new.run

# $ ruby inherit_test_setup.rb
# >>> starting test run: TestArray
# parent setup
# running TestArray#test_array
# true
# >>> starting test run: TestSomething
# parent setup
# child setup
# running TestSomething#test_something
# true