rails/activerecord/test/cases/attribute_test.rb

require 'cases/helper'
require 'minitest/mock'

module ActiveRecord
  class AttributeTest < ActiveRecord::TestCase
    setup do
      @type = Minitest::Mock.new
      @type.expect(:==, false, [false])
    end

    teardown do
      assert @type.verify
    end

    test "from_database + read type casts from database" do
      @type.expect(:deserialize, 'type cast from database', ['a value'])
      attribute = Attribute.from_database(nil, 'a value', @type)

      type_cast_value = attribute.value

      assert_equal 'type cast from database', type_cast_value
    end

    test "from_user + read type casts from user" do
      @type.expect(:cast, 'type cast from user', ['a value'])
      attribute = Attribute.from_user(nil, 'a value', @type)

      type_cast_value = attribute.value

      assert_equal 'type cast from user', type_cast_value
    end

    test "reading memoizes the value" do
      @type.expect(:deserialize, 'from the database', ['whatever'])
      attribute = Attribute.from_database(nil, 'whatever', @type)

      type_cast_value = attribute.value
      second_read = attribute.value

      assert_equal 'from the database', type_cast_value
      assert_same type_cast_value, second_read
    end

    test "reading memoizes falsy values" do
      @type.expect(:deserialize, false, ['whatever'])
      attribute = Attribute.from_database(nil, 'whatever', @type)

      attribute.value
      attribute.value
    end

    test "read_before_typecast returns the given value" do
      attribute = Attribute.from_database(nil, 'raw value', @type)

      raw_value = attribute.value_before_type_cast

      assert_equal 'raw value', raw_value
    end

    test "from_database + read_for_database type casts to and from database" do
      @type.expect(:deserialize, 'read from database', ['whatever'])
      @type.expect(:serialize, 'ready for database', ['read from database'])
      attribute = Attribute.from_database(nil, 'whatever', @type)

      serialize = attribute.value_for_database

      assert_equal 'ready for database', serialize
    end

    test "from_user + read_for_database type casts from the user to the database" do
      @type.expect(:cast, 'read from user', ['whatever'])
      @type.expect(:serialize, 'ready for database', ['read from user'])
      attribute = Attribute.from_user(nil, 'whatever', @type)

      serialize = attribute.value_for_database

      assert_equal 'ready for database', serialize
    end

    test "duping dups the value" do
      @type.expect(:deserialize, 'type cast', ['a value'])
      attribute = Attribute.from_database(nil, 'a value', @type)

      value_from_orig = attribute.value
      value_from_clone = attribute.dup.value
      value_from_orig << ' foo'

      assert_equal 'type cast foo', value_from_orig
      assert_equal 'type cast', value_from_clone
    end

    test "duping does not dup the value if it is not dupable" do
      @type.expect(:deserialize, false, ['a value'])
      attribute = Attribute.from_database(nil, 'a value', @type)

      assert_same attribute.value, attribute.dup.value
    end

    test "duping does not eagerly type cast if we have not yet type cast" do
      attribute = Attribute.from_database(nil, 'a value', @type)
      attribute.dup
    end

    class MyType
      def cast(value)
        value + " from user"
      end

      def deserialize(value)
        value + " from database"
      end
    end

    test "with_value_from_user returns a new attribute with the value from the user" do
      old = Attribute.from_database(nil, "old", MyType.new)
      new = old.with_value_from_user("new")

      assert_equal "old from database", old.value
      assert_equal "new from user", new.value
    end

    test "with_value_from_database returns a new attribute with the value from the database" do
      old = Attribute.from_user(nil, "old", MyType.new)
      new = old.with_value_from_database("new")

      assert_equal "old from user", old.value
      assert_equal "new from database", new.value
    end

    test "uninitialized attributes yield their name if a block is given to value" do
      block = proc { |name| name.to_s + "!" }
      foo = Attribute.uninitialized(:foo, nil)
      bar = Attribute.uninitialized(:bar, nil)

      assert_equal "foo!", foo.value(&block)
      assert_equal "bar!", bar.value(&block)
    end

    test "uninitialized attributes have no value" do
      assert_nil Attribute.uninitialized(:foo, nil).value
    end

    test "attributes equal other attributes with the same constructor arguments" do
      first = Attribute.from_database(:foo, 1, Type::Integer.new)
      second = Attribute.from_database(:foo, 1, Type::Integer.new)
      assert_equal first, second
    end

    test "attributes do not equal attributes with different names" do
      first = Attribute.from_database(:foo, 1, Type::Integer.new)
      second = Attribute.from_database(:bar, 1, Type::Integer.new)
      assert_not_equal first, second
    end

    test "attributes do not equal attributes with different types" do
      first = Attribute.from_database(:foo, 1, Type::Integer.new)
      second = Attribute.from_database(:foo, 1, Type::Float.new)
      assert_not_equal first, second
    end

    test "attributes do not equal attributes with different values" do
      first = Attribute.from_database(:foo, 1, Type::Integer.new)
      second = Attribute.from_database(:foo, 2, Type::Integer.new)
      assert_not_equal first, second
    end

    test "attributes do not equal attributes of other classes" do
      first = Attribute.from_database(:foo, 1, Type::Integer.new)
      second = Attribute.from_user(:foo, 1, Type::Integer.new)
      assert_not_equal first, second
    end

    test "an attribute has not been read by default" do
      attribute = Attribute.from_database(:foo, 1, Type::Value.new)
      assert_not attribute.has_been_read?
    end

    test "an attribute has been read when its value is calculated" do
      attribute = Attribute.from_database(:foo, 1, Type::Value.new)
      attribute.value
      assert attribute.has_been_read?
    end

    test "an attribute can not be mutated if it has not been read,
      and skips expensive calculations" do
      type_which_raises_from_all_methods = Object.new
      attribute = Attribute.from_database(:foo, "bar", type_which_raises_from_all_methods)

      assert_not attribute.changed_in_place_from?("bar")
    end
  end
end