getting No message given error in my Rails test

there are two models user and resident .. and both has one to one relationship (has_one) btw them. this is the test for the user(user-test.rb)

I m getting error in this test :

require 'test_helper'

class UserTest < ActiveSupport::TestCase

  def setup
    @resident = residents(:res1)
    @user = @resident.build_user(roll_number: "101303110", email: "user@example.com",password: "foobar", password_confirmation: "foobar")
  end
  test "should be valid" do
    assert @user.valid?
  end

  test "roll_number should be present" do
    @user.roll_number = "     "
    assert_not @user.valid?
  end

  test "email should be present" do
    @user.email = "     "
    assert_not @user.valid?
  end
  test "email should not be too long" do
    @user.email = "a" * 244 + "@example.com"
    assert_not @user.valid?
  end

  test "email validation should accept valid addresses" do
    valid_addresses = %w[user@example.com USER@foo.COM A_US-ER@foo.bar.org
                         first.last@foo.jp alice+bob@baz.cn]
    valid_addresses.each do |valid_address|
      @user.email = valid_address
      assert @user.valid?, "#{valid_address.inspect} should be valid"
    end
  end

  test "email validation should reject invalid addresses" do
    invalid_addresses = %w[user@example,com user_at_foo.org user.name@example.
                           foo@bar_baz.com foo@bar+baz.com]
    invalid_addresses.each do |invalid_address|
      @user.email = invalid_address
      assert_not @user.valid?, "#{invalid_address.inspect} should be invalid"
    end
  end

  test "email addresses should be unique" do
    duplicate_user = @user.dup
    duplicate_user.email = @user.email.upcase
    @user.save
    assert_not duplicate_user.valid?
  end

  test "password should be present (nonblank)" do
    @user.password = @user.password_confirmation = " " * 6
    assert_not @user.valid?
  end

  test "password should have a minimum length" do
    @user.password = @user.password_confirmation = "a" * 5
    assert_not @user.valid?
  end
  test "authenticated? should return false for a user with nil digest" do
    assert_not @user.authenticated?(:remember, '')
  end

end

After executing the test,error came is as follows :

 1) Failure:
ResidentTest#test_should_be_valid [/Users/nischaynamdev/RubymineProjects/hostel_mess_pay/test/models/resident_test.rb:9]:
Failed assertion, no message given.

18 runs, 25 assertions, 1 failures, 0 errors, 0 skips

user Model

the link for user model is as follows : Pls help me passing this test,I m trying since 30 minutes !