```ruby
require 'test_helper'

class UserTest < ActiveSupport::TestCase
  def setup
    @user = User.new(name: 'Example user', email: 'example@example.com')
  end

  test 'should be valid' do
    assert @user.valid?
  end

  test 'name should be present' do
    @user.name = '     '
    assert_not @user.valid?
  end

  test 'email should be present' do
    @user.email = ' '
    assert_not @user.valid?
  end

  test 'name should not be too long' do
    @user.name = "a" * 51
    assert_not @user.valid?
  end

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

Add email validation tests for user
user
```ruby
require 'test_helper'

class UserTest < ActiveSupport::TestCase
  def setup
    @user = User.new(name: 'Example user', email: 'example@example.com')
  end

  test 'should be valid' do
    assert @user.valid?
  end

  test 'name should be present' do
    @user.name = '     '
    assert_not @user.valid?
  end

  test 'email should be present' do
    @user.email = ' '
    assert_not @user.valid?
  end

  test 'name should not be too long' do
    @user.name = "a" * 51
    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 email 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 |address|
      @user.email = address
      assert @user.valid?, "#{address.inspect} should be valid"
    end
  end

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