invalid?

Performs the opposite of valid?. Returns true if errors were added, false otherwise.

class Person
  include ActiveModel::Validations

  attr_accessor :name
  validates_presence_of :name
end

person = Person.new
person.name = ''
person.invalid? # => true
person.name = 'david'
person.invalid? # => false

Context can optionally be supplied to define which callbacks to test against (the context is defined on the validations using :on).

class Person
  include ActiveModel::Validations

  attr_accessor :name
  validates_presence_of :name, on: :new
end

person = Person.new
person.invalid?       # => false
person.invalid?(:new) # => true