text: ﻿# Copyright (c) 2021, LE GOFF Vincent
  # All rights reserved.
  
  # Redistribution and use in source and binary forms, with or without
  # modification, are permitted provided that the following conditions are met:
  
  # * Redistributions of source code must retain the above copyright notice, this
  #   list of conditions and the following disclaimer.
  
  # * Redistributions in binary form must reproduce the above copyright notice,
  #   this list of conditions and the following disclaimer in the documentation
  #   and/or other materials provided with the distribution.
  
  # * Neither the name of ytranslate nor the names of its
  #   contributors may be used to endorse or promote products derived from
  #   this software without specific prior written permission.
  
  # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  # AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  # IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  # DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
  # FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  # DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  # SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  # CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  # OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  
  """Test the model API with a one-to-one relations."""
  
  from test.base import BaseTest
  
  from pygasus import Model
  from pygasus.exceptions import *
  
  class Book(Model):
  
      """A simple book model."""
  
      title: str
      author: "Author"
      year: int
  
  class Author(Model):
  
      """Book author."""
  
      last_name: str
      first_name: str
      book: "Book" = None
      born_in: int
  
  class TestOne2One(BaseTest):
  
      """Test the model API."""
  
      models = (Book, Author)
  
      def setUp(self):
          super().setUp()
  
      def test_create(self):
          """Create several books and authors, linking them."""
          dickens = Author.create(first_name="Charles", last_name="Dickens",
                  born_in=1812)
          carol = Book.create(title="A Christmas Carol", author=dickens, year=1843)
          self.assertIs(carol.author, dickens)
          self.assertIs(dickens.book, carol)
  
          # Create a second author and assign the book to it.
          london = Author.create(first_name="Jack", last_name="London",
                  born_in=1876, book=carol)
          self.assertIs(london.book, carol)
          self.assertIs(carol.author, london)
          self.assertIsNone(dickens.book)
  
      def test_update(self):
          """Test to update a one-to-one relation."""
          dickens = Author.create(first_name="Charles", last_name="Dickens",
                  born_in=1812)
          carol = Book.create(title="A Christmas Carol", author=dickens, year=1843)
          self.assertIs(carol.author, dickens)
          self.assertIs(dickens.book, carol)
  
          # Create a second author and assign the book to it.
          london = Author.create(first_name="Jack", last_name="London",
                  born_in=1876)
          self.assertIsNone(london.book)
  
          # The book changes author.
          carol.author = london
          self.assertIs(carol.author, london)
          self.assertIs(london.book, carol)
          self.assertIsNone(dickens.book)
  
          # Dickens reassert ownership of the book.
          dickens.book = carol
          self.assertIs(carol.author, dickens)
          self.assertIs(dickens.book, carol)
          self.assertIsNone(london.book)
  
      def test_get(self):
          """Test to get an instance."""
          dickens = Author.create(first_name="Charles", last_name="Dickens",
                  born_in=1812)
          carol = Book.create(title="A Christmas Carol", author=dickens, year=1843)
          self.assertIs(carol.author, dickens)
          self.assertIs(dickens.book, carol)
  
          # Clear the ID mapper.
          self.db.id_mapper.clear()
          carol = Book.get(id=carol.id)
          dickens = Author.get(id=dickens.id)
          self.assertIs(Book.get(author=dickens), carol)
          self.assertIs(Author.get(book=carol), dickens)
  
      def test_select(self):
          """Test to select the relevant objects from a relation."""
          dickens = Author.create(first_name="Charles", last_name="Dickens",
                  born_in=1812)
          carol = Book.create(title="A Christmas Carol", author=dickens, year=1843)
          london = Author.create(first_name="Jack", last_name="London",
                  born_in=1876)
          bellew = Book.create(title="Smoke Bellew",
                  author=london, year=1912)
          self.assertIs(carol.author, dickens)
          self.assertIs(dickens.book, carol)
          self.assertIs(bellew.author, london)
          self.assertIs(london.book, bellew)
  
          # Select books and authors.
          results = list(Book.select(Book.author == london))
          self.assertIn(bellew, results)
          self.assertNotIn(carol, results)
          results = list(Author.select(Author.book == bellew))
          self.assertIn(london, results)
          self.assertNotIn(dickens, results)
  