from ddf import G
    from my_library import Author, Book

    def test_search_book_by_author():
        author1 = G(Author)
        author2 = G(Author)
        book1 = G(Book, authors=[author1])
        book2 = G(Book, authors=[author2])
        books = Book.objects.search_by_author(author1.name)
        assert book1 in books
        assert book2 not in books

    from ddf import G

    def test_search_book_by_author():
        author1, author2 = G('my_library.Author', n=2)
        book1 = G('my_library.Book', authors=[author1])
        book2 = G('my_library.Book', authors=[author2])
        books = Book.objects.search_by_author(author1.name)
        assert book1 in books
        assert book2 not in books

    from ddf import G

    def test_search_book_by_author():
        book1 = G(Book, main_author__name='Eistein')
        book2 = G(Book)
        books = Book.objects.search_by_author(book1.main_author.name)
        assert book1 in books
        assert book2 not in books
        assert book1.main_author.name == 'Eistein'

# Import the main DDF features
from ddf import N, G, F, M, C, P, teach # meaning: New, Get, ForeignKey, Mask, Copier, Print, teach

# `N` creates an instance of model without saving it to DB
instance = N(Book)

# `G` creates an instance of model and save it into the DB
instance = G(Book)

# `F` customize relationship objects
instance = G(Book, author=F(name='Eistein'))
# Same as `F`
instance = G(Book, author__name='Eistein')

# `M` receives a data mask and create a random string using it
# Known symbols: `_`, `#` or `-`
# To escape known symbols: `!`
instance = N(Book, address=M('Street ___, ### !- --'))
assert instance.address == 'Street TPA, 632 - BR'

# `C` copies data from one field to another
instance = N(Book, address_formatted=C('address'), address=M('Street ___, ### \- --'))
assert instance.address_formatted == 'Street TPA, 632 - BR'

# `teach` teaches DDF in how to build an instance
teach(Book, address=M('Street ___, ### !- --'))
instance = G(Book)
assert instance.address == 'Street TPA, 632 - BR'

# `P` print instance values for debugging
P(instance)

import ddf
ddf.__version__

from ddf import ddf_check_models
succeeded, errors = ddf_check_models()
succeeded, errors = ddf_check_models(print_csv=True)
succeeded, errors = ddf_check_models(csv_filename='ddf_compatibility_report.csv')