Module: Shoulda::Matchers::ActiveModel

The allow_value matcher is used to test that an attribute of a model can or cannot be set to a particular value or values. It is most commonly used in conjunction with the validates_format_of validation.

should

In the positive form, allow_value asserts that an attribute can be set to one or more values, succeeding if none of the values cause the record to be invalid:

class UserProfile
  include ActiveModel::Model
  attr_accessor :website_url

  validates_format_of :website_url, with: URI.regexp
end

# RSpec
describe UserProfile do
  it do
    should allow_value('http://foo.com', 'http://bar.com/baz').
      for(:website_url)
  end
end

# Test::Unit
class UserProfileTest < ActiveSupport::TestCase
  should allow_value('http://foo.com', 'http://bar.com/baz').
    for(:website_url)
end

should_not

In the negative form, allow_value asserts that an attribute cannot be set to one or more values, succeeding if the first value causes the record to be invalid.

This can be surprising so in this case if you need to check that all of the values are invalid, use separate assertions:

class UserProfile
  include ActiveModel::Model
  attr_accessor :website_url

  validates_format_of :website_url, with: URI.regexp
end

describe UserProfile do
  # One assertion: 'buz' and 'bar' will not be tested
  it { should_not allow_value('fiz', 'buz', 'bar').for(:website_url) }

  # Three assertions, all tested separately
  it { should_not allow_value('fiz').for(:website_url) }
  it { should_not allow_value('buz').for(:website_url) }
  it { should_not allow_value('bar').for(:website_url) }
end

Qualifiers

on

Use on if your validation applies only under a certain context.

class UserProfile
  include ActiveModel::Model
  attr_accessor :birthday_as_string

  validates_format_of :birthday_as_string,
    with: /^(\d+)-(\d+)-(\d+)$/,
    on: :create
end

# RSpec
describe UserProfile do
  it do
    should allow_value('2013-01-01').
      for(:birthday_as_string).
      on(:create)
  end
end

# Test::Unit
class UserProfileTest < ActiveSupport::TestCase
  should allow_value('2013-01-01').
    for(:birthday_as_string).
    on(:create)
end

with_message

Use with_message if you are using a custom validation message.

class UserProfile
  include ActiveModel::Model
  attr_accessor :state

  validates_format_of :state,
    with: /^(open|closed)$/,
    message: 'State must be open or closed'
end

# RSpec
describe UserProfile do
  it do
    should allow_value('open', 'closed').
      for(:state).
      with_message('State must be open or closed')
  end
end

# Test::Unit
class UserProfileTest < ActiveSupport::TestCase
  should allow_value('open', 'closed').
    for(:state).
    with_message('State must be open or closed')
end

Use with_message with a regexp to perform a partial match:

class UserProfile
  include ActiveModel::Model
  attr_accessor :state

  validates_format_of :state,
    with: /^(open|closed)$/,
    message: 'State must be open or closed'
end

# RSpec
describe UserProfile do
  it do
    should allow_value('open', 'closed').
      for(:state).
      with_message(/open or closed/)
  end
end

# Test::Unit
class UserProfileTest < ActiveSupport::TestCase
  should allow_value('open', 'closed').
    for(:state).
    with_message(/open or closed/)
end

Use with_message with the :against option if the attribute the validation message is stored under is different from the attribute being validated:

class UserProfile
  include ActiveModel::Model
  attr_accessor :sports_team

  validate :sports_team_must_be_valid

  private

  def sports_team_must_be_valid
    if sports_team !~ /^(Broncos|Titans)$/i
      self.errors.add :chosen_sports_team,
        'Must be either a Broncos fan or a Titans fan'
    end
  end
end

# RSpec
describe UserProfile do
  it do
    should allow_value('Broncos', 'Titans').
      for(:sports_team).
      with_message('Must be either a Broncos or Titans fan',
        against: :chosen_sports_team
      )
  end
end

# Test::Unit
class UserProfileTest < ActiveSupport::TestCase
  should allow_value('Broncos', 'Titans').
    for(:sports_team).
    with_message('Must be either a Broncos or Titans fan',
      against: :chosen_sports_team
    )
end

The have_secure_password matcher tests usage of the has_secure_password macro.

Example

class User
  include ActiveModel::Model
  include ActiveModel::SecurePassword
  attr_accessor :password

  has_secure_password
end

# RSpec
describe User do
  it { should have_secure_password }
end

# Test::Unit
class UserTest < ActiveSupport::TestCase
  should have_secure_password
end

The validate_absence_of matcher tests the usage of the validates_absence_of validation.

class Artillery
  include ActiveModel::Model
  attr_accessor :arms

  validates_absence_of :arms
end

# RSpec
describe Artillery do
  it { should validate_absence_of(:arms) }
end

# Test::Unit
class ArtilleryTest < ActiveSupport::TestCase
  should validate_absence_of(:arms)
end

Qualifiers

on

Use on if your validation applies only under a certain context.

class Artillery
  include ActiveModel::Model
  attr_accessor :arms

  validates_absence_of :arms, on: :create
end

# RSpec
describe Artillery do
  it { should validate_absence_of(:arms).on(:create) }
end

# Test::Unit
class ArtilleryTest < ActiveSupport::TestCase
  should validate_absence_of(:arms).on(:create)
end

with_message

Use with_message if you are using a custom validation message.

class Artillery
  include ActiveModel::Model
  attr_accessor :arms

  validates_absence_of :arms,
    message: "We're fresh outta arms here, soldier!"
end

# RSpec
describe Artillery do
  it do
    should validate_absence_of(:arms).
      with_message("We're fresh outta arms here, soldier!")
  end
end

# Test::Unit
class ArtilleryTest < ActiveSupport::TestCase
  should validate_absence_of(:arms).
    with_message("We're fresh outta arms here, soldier!")
end

The validate_acceptance_of matcher tests usage of the validates_acceptance_of validation.

class Registration
  include ActiveModel::Model
  attr_accessor :eula

  validates_acceptance_of :eula
end

# RSpec
describe Registration do
  it { should validate_acceptance_of(:eula) }
end

# Test::Unit
class RegistrationTest < ActiveSupport::TestCase
  should validate_acceptance_of(:eula)
end

Qualifiers

on

Use on if your validation applies only under a certain context.

class Registration
  include ActiveModel::Model
  attr_accessor :terms_of_service

  validates_acceptance_of :terms_of_service, on: :create
end

# RSpec
describe Registration do
  it do
    should validate_acceptance_of(:terms_of_service).
      on(:create)
  end
end

# Test::Unit
class RegistrationTest < ActiveSupport::TestCase
  should validate_acceptance_of(:terms_of_service).on(:create)
end

with_message

Use with_message if you are using a custom validation message.

class Registration
  include ActiveModel::Model
  attr_accessor :terms_of_service

  validates_acceptance_of :terms_of_service,
    message: 'You must accept the terms of service'
end

# RSpec
describe Registration do
  it do
    should validate_acceptance_of(:terms_of_service).
      with_message('You must accept the terms of service')
  end
end

# Test::Unit
class RegistrationTest < ActiveSupport::TestCase
  should validate_acceptance_of(:terms_of_service).
    with_message('You must accept the terms of service')
end

The validate_confirmation_of matcher tests usage of the validates_confirmation_of validation.

class User
  include ActiveModel::Model
  attr_accessor :email

  validates_confirmation_of :email
end

# RSpec
describe User do
  it { should validate_confirmation_of(:email) }
end

# Test::Unit
class UserTest < ActiveSupport::TestCase
  should validate_confirmation_of(:email)
end

Qualifiers

on

Use on if your validation applies only under a certain context.

class User
  include ActiveModel::Model
  attr_accessor :password

  validates_confirmation_of :password, on: :create
end

# RSpec
describe User do
  it { should validate_confirmation_of(:password).on(:create) }
end

# Test::Unit
class UserTest < ActiveSupport::TestCase
  should validate_confirmation_of(:password).on(:create)
end

with_message

Use with_message if you are using a custom validation message.

class User
  include ActiveModel::Model
  attr_accessor :password

  validates_confirmation_of :password,
    message: 'Please re-enter your password'
end

# RSpec
describe User do
  it do
    should validate_confirmation_of(:password).
      with_message('Please re-enter your password')
  end
end

# Test::Unit
class UserTest < ActiveSupport::TestCase
  should validate_confirmation_of(:password).
    with_message('Please re-enter your password')
end

The validate_exclusion_of matcher tests usage of the validates_exclusion_of validation, asserting that an attribute cannot take a blacklist of values, and inversely, can take values outside of this list.

If your blacklist is an array of values, use in_array:

class Game
  include ActiveModel::Model
  attr_accessor :supported_os

  validates_exclusion_of :supported_os, in: ['Mac', 'Linux']
end

# RSpec
describe Game do
  it do
    should validate_exclusion_of(:supported_os).
      in_array(['Mac', 'Linux'])
  end
end

# Test::Unit
class GameTest < ActiveSupport::TestCase
  should validate_exclusion_of(:supported_os).
    in_array(['Mac', 'Linux'])
end

If your blacklist is a range of values, use in_range:

class Game
  include ActiveModel::Model
  attr_accessor :supported_os

  validates_exclusion_of :supported_os, in: ['Mac', 'Linux']
end

# RSpec
describe Game do
  it do
    should validate_exclusion_of(:floors_with_enemies).
      in_range(5..8)
  end
end

# Test::Unit
class GameTest < ActiveSupport::TestCase
  should validate_exclusion_of(:floors_with_enemies).
    in_range(5..8)
end

Qualifiers

on

Use on if your validation applies only under a certain context.

class Game
  include ActiveModel::Model
  attr_accessor :weapon

  validates_exclusion_of :weapon,
    in: ['pistol', 'paintball gun', 'stick'],
    on: :create
end

# RSpec
describe Game do
  it do
    should validate_exclusion_of(:weapon).
      in_array(['pistol', 'paintball gun', 'stick']).
      on(:create)
  end
end

# Test::Unit
class GameTest < ActiveSupport::TestCase
  should validate_exclusion_of(:weapon).
    in_array(['pistol', 'paintball gun', 'stick']).
    on(:create)
end

with_message

Use with_message if you are using a custom validation message.

class Game
  include ActiveModel::Model
  attr_accessor :weapon

  validates_exclusion_of :weapon,
    in: ['pistol', 'paintball gun', 'stick'],
    message: 'You chose a puny weapon'
end

# RSpec
describe Game do
  it do
    should validate_exclusion_of(:weapon).
      in_array(['pistol', 'paintball gun', 'stick']).
      with_message('You chose a puny weapon')
  end
end

# Test::Unit
class GameTest < ActiveSupport::TestCase
  should validate_exclusion_of(:weapon).
    in_array(['pistol', 'paintball gun', 'stick']).
    with_message('You chose a puny weapon')
end

The validate_inclusion_of matcher tests usage of the validates_inclusion_of validation, asserting that an attribute can take a whitelist of values and cannot take values outside of this list.

If your whitelist is an array of values, use in_array:

class Issue
  include ActiveModel::Model
  attr_accessor :state

  validates_inclusion_of :state, in: %w(open resolved unresolved)
end

# RSpec
describe Issue do
  it do
    should validate_inclusion_of(:state).
      in_array(%w(open resolved unresolved))
  end
end

# Test::Unit
class IssueTest < ActiveSupport::TestCase
  should validate_inclusion_of(:state).
    in_array(%w(open resolved unresolved))
end

If your whitelist is a range of values, use in_range:

class Issue
  include ActiveModel::Model
  attr_accessor :priority

  validates_inclusion_of :priority, in: 1..5
end

# RSpec
describe Issue do
  it { should validate_inclusion_of(:state).in_range(1..5) }
end

# Test::Unit
class IssueTest < ActiveSupport::TestCase
  should validate_inclusion_of(:state).in_range(1..5)
end

Caveats

We discourage using validate_inclusion_of with boolean columns. In fact, there is never a case where a boolean column will be anything but true, false, or nil, as ActiveRecord will type-cast an incoming value to one of these three values. That means there isn't any way we can refute this logic in a test. Hence, this will produce a warning:

it { should validate_inclusion_of(:imported).in_array([true, false]) }

The only case where validate_inclusion_of could be appropriate is for ensuring that a boolean column accepts nil, but we recommend using allow_value instead, like this:

it { should allow_value(nil).for(:imported) }

Qualifiers

Use on if your validation applies only under a certain context.

class Issue
  include ActiveModel::Model
  attr_accessor :severity

  validates_inclusion_of :severity,
    in: %w(low medium high),
    on: :create
end

# RSpec
describe Issue do
  it do
    should validate_inclusion_of(:severity).
      in_array(%w(low medium high)).
      on(:create)
  end
end

# Test::Unit
class IssueTest < ActiveSupport::TestCase
  should validate_inclusion_of(:severity).
    in_array(%w(low medium high)).
    on(:create)
end

with_message

Use with_message if you are using a custom validation message.

class Issue
  include ActiveModel::Model
  attr_accessor :severity

  validates_inclusion_of :severity,
    in: %w(low medium high),
    message: 'Severity must be low, medium, or high'
end

# RSpec
describe Issue do
  it do
    should validate_inclusion_of(:severity).
      in_array(%w(low medium high)).
      with_message('Severity must be low, medium, or high')
  end
end

# Test::Unit
class IssueTest < ActiveSupport::TestCase
  should validate_inclusion_of(:severity).
    in_array(%w(low medium high)).
    with_message('Severity must be low, medium, or high')
end

with_low_message

Use with_low_message if you have a custom validation message for when a given value is too low.

class Person
  include ActiveModel::Model
  attr_accessor :age

  validate :age_must_be_valid

  private

  def age_must_be_valid
    if age < 65
      self.errors.add :age, 'You do not receive any benefits'
    end
  end
end

# RSpec
describe Person do
  it do
    should validate_inclusion_of(:age).
      in_range(0..65).
      with_low_message('You do not receive any benefits')
  end
end

# Test::Unit
class PersonTest < ActiveSupport::TestCase
  should validate_inclusion_of(:age).
    in_range(0..65).
    with_low_message('You do not receive any benefits')
end

with_high_message

Use with_high_message if you have a custom validation message for when a given value is too high.

class Person
  include ActiveModel::Model
  attr_accessor :age

  validate :age_must_be_valid

  private

  def age_must_be_valid
    if age > 21
      self.errors.add :age, "You're too old for this stuff"
    end
  end
end

# RSpec
describe Person do
  it do
    should validate_inclusion_of(:age).
      in_range(0..21).
      with_high_message("You're too old for this stuff")
  end
end

# Test::Unit
class PersonTest < ActiveSupport::TestCase
  should validate_inclusion_of(:age).
    in_range(0..21).
    with_high_message("You're too old for this stuff")
end

allow_nil

Use allow_nil to assert that the attribute allows nil.

class Issue
  include ActiveModel::Model
  attr_accessor :state

  validates_presence_of :state
  validates_inclusion_of :state,
    in: %w(open resolved unresolved),
    allow_nil: true
end

# RSpec
describe Issue do
  it do
    should validate_inclusion_of(:state).
      in_array(%w(open resolved unresolved)).
      allow_nil
  end
end

# Test::Unit
class IssueTest < ActiveSupport::TestCase
  should validate_inclusion_of(:state).
    in_array(%w(open resolved unresolved)).
    allow_nil
end

allow_blank

Use allow_blank to assert that the attribute allows blank.

class Issue
  include ActiveModel::Model
  attr_accessor :state

  validates_presence_of :state
  validates_inclusion_of :state,
    in: %w(open resolved unresolved),
    allow_blank: true
end

# RSpec
describe Issue do
  it do
    should validate_inclusion_of(:state).
      in_array(%w(open resolved unresolved)).
      allow_blank
  end
end

# Test::Unit
class IssueTest < ActiveSupport::TestCase
  should validate_inclusion_of(:state).
    in_array(%w(open resolved unresolved)).
    allow_blank
end

The validate_length_of matcher tests usage of the validates_length_of matcher. Note that this matcher is intended to be used against string columns and not integer columns.

Qualifiers

Use on if your validation applies only under a certain context.

class User
  include ActiveModel::Model
  attr_accessor :password

  validates_length_of :password, minimum: 10, on: :create
end

# RSpec
describe User do
  it do
    should validate_length_of(:password).
      is_at_least(10).
      on(:create)
  end
end

# Test::Unit
class UserTest < ActiveSupport::TestCase
  should validate_length_of(:password).
    is_at_least(10).
    on(:create)
end

is_at_least

Use is_at_least to test usage of the :minimum option. This asserts that the attribute can take a string which is equal to or longer than the given length and cannot take a string which is shorter.

class User
  include ActiveModel::Model
  attr_accessor :bio

  validates_length_of :bio, minimum: 15
end

# RSpec

describe User do
  it { should validate_length_of(:bio).is_at_least(15) }
end

# Test::Unit

class UserTest < ActiveSupport::TestCase
  should validate_length_of(:bio).is_at_least(15)
end

is_at_most

Use is_at_most to test usage of the :maximum option. This asserts that the attribute can take a string which is equal to or shorter than the given length and cannot take a string which is longer.

class User
  include ActiveModel::Model
  attr_accessor :status_update

  validates_length_of :status_update, maximum: 140
end

# RSpec
describe User do
  it { should validate_length_of(:status_update).is_at_most(140) }
end

# Test::Unit
class UserTest < ActiveSupport::TestCase
  should validate_length_of(:status_update).is_at_most(140)
end

is_equal_to

Use is_equal_to to test usage of the :is option. This asserts that the attribute can take a string which is exactly equal to the given length and cannot take a string which is shorter or longer.

class User
  include ActiveModel::Model
  attr_accessor :favorite_superhero

  validates_length_of :favorite_superhero, is: 6
end

# RSpec
describe User do
  it { should validate_length_of(:favorite_superhero).is_equal_to(6) }
end

# Test::Unit
class UserTest < ActiveSupport::TestCase
  should validate_length_of(:favorite_superhero).is_equal_to(6)
end

is_at_least + is_at_most

Use is_at_least and is_at_most together to test usage of the :in option.

class User
  include ActiveModel::Model
  attr_accessor :password

  validates_length_of :password, in: 5..30
end

# RSpec
describe User do
  it do
    should validate_length_of(:password).
      is_at_least(5).is_at_most(30)
  end
end

# Test::Unit
class UserTest < ActiveSupport::TestCase
  should validate_length_of(:password).
    is_at_least(5).is_at_most(30)
end

with_message

Use with_message if you are using a custom validation message.

class User
  include ActiveModel::Model
  attr_accessor :password

  validates_length_of :password,
    minimum: 10,
    message: "Password isn't long enough"
end

# RSpec
describe User do
  it do
    should validate_length_of(:password).
      is_at_least(10).
      with_message("Password isn't long enough")
  end
end

# Test::Unit
class UserTest < ActiveSupport::TestCase
  should validate_length_of(:password).
    is_at_least(10).
    with_message("Password isn't long enough")
end

with_short_message

Use with_short_message if you are using a custom "too short" message.

class User
  include ActiveModel::Model
  attr_accessor :secret_key

  validates_length_of :secret_key,
    in: 15..100,
    too_short: 'Secret key must be more than 15 characters'
end

# RSpec
describe User do
  it do
    should validate_length_of(:secret_key).
      is_at_least(15).
      with_short_message('Secret key must be more than 15 characters')
  end
end

# Test::Unit
class UserTest < ActiveSupport::TestCase
  should validate_length_of(:secret_key).
    is_at_least(15).
    with_short_message('Secret key must be more than 15 characters')
end

with_long_message

Use with_long_message if you are using a custom "too long" message.

class User
  include ActiveModel::Model
  attr_accessor :secret_key

  validates_length_of :secret_key,
    in: 15..100,
    too_long: 'Secret key must be less than 100 characters'
end

# RSpec
describe User do
  it do
    should validate_length_of(:secret_key).
      is_at_most(100).
      with_long_message('Secret key must be less than 100 characters')
  end
end

# Test::Unit
class UserTest < ActiveSupport::TestCase
  should validate_length_of(:secret_key).
    is_at_most(100).
    with_long_message('Secret key must be less than 100 characters')
end

The validate_numericality_of matcher tests usage of the validates_numericality_of validation.

class Person
  include ActiveModel::Model
  attr_accessor :gpa

  validates_numericality_of :gpa
end

# RSpec
describe Person do
  it { should validate_numericality_of(:gpa) }
end

# Test::Unit
class PersonTest < ActiveSupport::TestCase
  should validate_numericality_of(:gpa)
end

Qualifiers

on

Use on if your validation applies only under a certain context.

class Person
  include ActiveModel::Model
  attr_accessor :number_of_dependents

  validates_numericality_of :number_of_dependents, on: :create
end

# RSpec
describe Person do
  it do
    should validate_numericality_of(:number_of_dependents).
      on(:create)
  end
end

# Test::Unit
class PersonTest < ActiveSupport::TestCase
  should validate_numericality_of(:number_of_dependents).on(:create)
end

only_integer

Use only_integer to test usage of the :only_integer option. This asserts that your attribute only allows integer numbers and disallows non-integer ones.

class Person
  include ActiveModel::Model
  attr_accessor :age

  validates_numericality_of :age, only_integer: true
end

# RSpec
describe Person do
  it { should validate_numericality_of(:age).only_integer }
end

# Test::Unit
class PersonTest < ActiveSupport::TestCase
  should validate_numericality_of(:age).only_integer
end

is_less_than

Use is_less_than to test usage of the the :less_than option. This asserts that the attribute can take a number which is less than the given value and cannot take a number which is greater than or equal to it.

class Person
  include ActiveModel::Model
  attr_accessor :number_of_cars

  validates_numericality_of :number_of_cars, less_than: 2
end

# RSpec
describe Person do
  it do
    should validate_numericality_of(:number_of_cars).
      is_less_than(2)
  end
end

# Test::Unit
class PersonTest < ActiveSupport::TestCase
  should validate_numericality_of(:number_of_cars).
    is_less_than(2)
end

is_less_than_or_equal_to

Use is_less_than_or_equal_to to test usage of the :less_than_or_equal_to option. This asserts that the attribute can take a number which is less than or equal to the given value and cannot take a number which is greater than it.

class Person
  include ActiveModel::Model
  attr_accessor :birth_year

  validates_numericality_of :birth_year, less_than_or_equal_to: 1987
end

# RSpec
describe Person do
  it do
    should validate_numericality_of(:birth_year).
      is_less_than_or_equal_to(1987)
  end
end

# Test::Unit
class PersonTest < ActiveSupport::TestCase
  should validate_numericality_of(:birth_year).
    is_less_than_or_equal_to(1987)
end

is_equal_to

Use is_equal_to to test usage of the :equal_to option. This asserts that the attribute can take a number which is equal to the given value and cannot take a number which is not equal.

class Person
  include ActiveModel::Model
  attr_accessor :weight

  validates_numericality_of :weight, equal_to: 150
end

# RSpec
describe Person do
  it { should validate_numericality_of(:weight).is_equal_to(150) }
end

# Test::Unit
class PersonTest < ActiveSupport::TestCase
  should validate_numericality_of(:weight).is_equal_to(150)
end

is_greater_than_or_equal_to

Use is_greater_than_or_equal_to to test usage of the :greater_than_or_equal_to option. This asserts that the attribute can take a number which is greater than or equal to the given value and cannot take a number which is less than it.

class Person
  include ActiveModel::Model
  attr_accessor :height

  validates_numericality_of :height, greater_than_or_equal_to: 55
end

# RSpec
describe Person do
  it do
    should validate_numericality_of(:height).
      is_greater_than_or_equal_to(55)
  end
end

# Test::Unit
class PersonTest < ActiveSupport::TestCase
  should validate_numericality_of(:height).
    is_greater_than_or_equal_to(55)
end

is_greater_than

Use is_greater_than to test usage of tthe :greater_than option. This asserts that the attribute can take a number which is greater than the given value and cannot take a number less than or equal to it.

class Person
  include ActiveModel::Model
  attr_accessor :legal_age

  validates_numericality_of :legal_age, greater_than: 21
end

# RSpec
describe Person do
  it do
    should validate_numericality_of(:legal_age).
      is_greater_than(21)
  end
end

# Test::Unit
class PersonTest < ActiveSupport::TestCase
  should validate_numericality_of(:legal_age).
    is_greater_than(21)
end

even

Use even to test usage of the :even option. This asserts that the attribute can take odd numbers and cannot take even ones.

class Person
  include ActiveModel::Model
  attr_accessor :birth_month

  validates_numericality_of :birth_month, even: true
end

# RSpec
describe Person do
  it { should validate_numericality_of(:birth_month).even }
end

# Test::Unit
class PersonTest < ActiveSupport::TestCase
  should validate_numericality_of(:birth_month).even
end

odd

Use odd to test usage of the :odd option. This asserts that the attribute can take a number which is odd and cannot take a number which is even.

class Person
  include ActiveModel::Model
  attr_accessor :birth_day

  validates_numericality_of :birth_day, odd: true
end

# RSpec
describe Person do
  it { should validate_numericality_of(:birth_day).odd }
end

# Test::Unit
class PersonTest < ActiveSupport::TestCase
  should validate_numericality_of(:birth_day).odd
end

with_message

Use with_message if you are using a custom validation message.

class Person
  include ActiveModel::Model
  attr_accessor :number_of_dependents

  validates_numericality_of :number_of_dependents,
    message: 'Number of dependents must be a number'
end

# RSpec
describe Person do
  it do
    should validate_numericality_of(:number_of_dependents).
      with_message('Number of dependents must be a number')
  end
end

# Test::Unit
class PersonTest < ActiveSupport::TestCase
  should validate_numericality_of(:number_of_dependents).
    with_message('Number of dependents must be a number')
end

allow_nil

Use allow_nil to assert that the attribute allows nil.

class Age
  include ActiveModel::Model
  attr_accessor :age

  validates_numericality_of :age, allow_nil: true
end

# RSpec
describe Post do
  it { should validate_numericality_of(:age).allow_nil }
end

# Test::Unit
class PostTest < ActiveSupport::TestCase
  should validate_numericality_of(:age).allow_nil
end

The validate_presence_of matcher tests usage of the validates_presence_of validation.

class Robot
  include ActiveModel::Model
  attr_accessor :arms

  validates_presence_of :arms
end

# RSpec
describe Robot do
  it { should validate_presence_of(:arms) }
end

# Test::Unit
class RobotTest < ActiveSupport::TestCase
  should validate_presence_of(:arms)
end

Caveats

Under Rails 4 and greater, if your model has_secure_password and you are validating presence of the password using a record whose password has already been set prior to calling the matcher, you will be instructed to use a record whose password is empty instead.

For example, given this scenario:

class User < ActiveRecord::Base
  has_secure_password validations: false

  validates_presence_of :password
end

describe User do
  subject { User.new(password: '123456') }

  it { should validate_presence_of(:password) }
end

the above test will raise an error like this:

The validation failed because your User model declares
`has_secure_password`, and `validate_presence_of` was called on a
user which has `password` already set to a value. Please use a user
with an empty `password` instead.

This happens because has_secure_password itself overrides your model so that it is impossible to set password to nil. This means that it is impossible to test that setting password to nil places your model in an invalid state (which in turn means that the validation itself is unnecessary).

Qualifiers

on

Use on if your validation applies only under a certain context.

class Robot
  include ActiveModel::Model
  attr_accessor :arms

  validates_presence_of :arms, on: :create
end

# RSpec
describe Robot do
  it { should validate_presence_of(:arms).on(:create) }
end

# Test::Unit
class RobotTest < ActiveSupport::TestCase
  should validate_presence_of(:arms).on(:create)
end

with_message

Use with_message if you are using a custom validation message.

class Robot
  include ActiveModel::Model
  attr_accessor :legs

  validates_presence_of :legs, message: 'Robot has no legs'
end

# RSpec
describe Robot do
  it do
    should validate_presence_of(:legs).
      with_message('Robot has no legs')
  end
end

# Test::Unit
class RobotTest < ActiveSupport::TestCase
  should validate_presence_of(:legs).
    with_message('Robot has no legs')
end