class QueryResultProxyTest(PythonicTestCase):
def setUp(self):
self.engine = create_engine('sqlite:///:memory:')
self.session = self._create_session()
self._populate_database()
self.query = self.session.query(User).order_by(asc(User.id))
self.proxy = QueryResultProxy(self.query)
def _tearDown(self):
Base.metadata.drop_all(self.engine)
def _create_session(self):
Base.metadata.create_all(self.engine)
Session = sessionmaker(bind=self.engine)
return Session()
def _populate_database(self):
for i, name in enumerate(('foo', 'bar', 'baz', 'quux', 'quuux')):
self.session.add(User(name, i))
self.session.commit()
def _next_name(self):
items = self.proxy.fetch(n=1)
return items[0].name
def _next_names(self, n=1):
return self._names(self.proxy.fetch(n=n))
def _names(self, results):
return [item.name for item in results]
def _name(self, result):
return result.name
def test_can_fetch_next_item(self):
assert_equals('foo', self._next_name())
assert_equals('bar', self._next_name())
assert_equals('baz', self._next_name())
def test_can_fetch_single_item(self):
filter_ = lambda item: item.activity >= 4
self.proxy = QueryResultProxy(self.query, filter_=filter_)
assert_equals('quuux', self._name(self.proxy.first()))
assert_equals(None, self.proxy.first())
def test_can_fetch_multiple_items_at_once(self):
assert_equals(['foo', 'bar'], self._next_names(n=2))
assert_equals(['baz', 'quux'], self._next_names(n=2))
assert_equals(['quuux'], self._next_names(n=2))
assert_equals([], self._next_names(n=2))
def test_regression_do_not_skipped_items_because_of_prefetching(self):
assert_equals('foo', self._next_name())
assert_equals(['bar', 'baz'], self._next_names(n=2))
assert_equals(['quux', 'quuux'], self._next_names(n=2))
def test_can_tell_if_more_items_are_available_even_before_explicit_fetching(self):
assert_true(self.proxy.more_available())
assert_equals('foo', self._next_name())
def test_can_tell_if_no_more_items_are_available(self):
assert_equals(['foo', 'bar', 'baz', 'quux'], self._next_names(n=4))
assert_true(self.proxy.more_available())
assert_equals('quuux', self._next_name())
assert_false(self.proxy.more_available())
def test_does_not_omit_prefetched_items_after_asking_if_more_are_available(self):
assert_true(self.proxy.more_available())
assert_equals(['foo', 'bar'], self._next_names(n=2))
def test_does_not_omit_prefetched_items_if_many_prefetched_items_were_available(self):
assert_true(self.proxy.more_available())
# more_available() should have fetched more than one item so we have
# actually 2+ items prefetched.
assert_not_equals(0, len(self.proxy._prefetched_items))
# .next() consumes only one item so there should be one left
# (._prefetched_items were overwritten in this step)
assert_equals(['foo'], self._names([self.proxy.next()]))
assert_not_equals(0, len(self.proxy._prefetched_items))
assert_equals(['bar', 'baz'], self._next_names(n=2))
def test_can_initialize_proxy_with_offset(self):
self.proxy = QueryResultProxy(self.query, start=2)
assert_equals(['baz', 'quux'], self._next_names(n=2))
def test_can_specify_filter_callable(self):
filter_ = lambda item: item.activity % 2 == 1
self.proxy = QueryResultProxy(self.query, filter_=filter_)
assert_equals(['bar', 'quux'], self._next_names(n=5))
assert_false(self.proxy.more_available())
def test_proxy_returns_always_specified_number_of_items_if_possible(self):
filter_ = lambda item: item.activity >= 2
self.proxy = QueryResultProxy(self.query, filter_=filter_)
assert_equals(['baz', 'quux', 'quuux'], self._next_names(n=3))
assert_false(self.proxy.more_available())
# --- limit ----------------------------------------------------------------
def test_can_limit_items_returned_by_iteration(self):
self.proxy = QueryResultProxy(self.query).limit(2)
assert_equals(['foo', 'bar'], self._names(self.proxy))
self.proxy = QueryResultProxy(self.query).limit(20)
assert_equals(['foo', 'bar', 'baz', 'quux', 'quuux'], self._names(self.proxy))
def test_accepts_strings_for_limit(self):
# that's what SQLAlchemy does (sic!)
self.proxy = QueryResultProxy(self.query).limit('1')
assert_equals(['foo'], self._names(self.proxy))
# --- offset ---------------------------------------------------------------
def test_can_offset_for_iteration(self):
self.proxy = QueryResultProxy(self.query).offset(3)
assert_equals(['quux', 'quuux'], self._names(self.proxy))
def test_accepts_strings_for_offset(self):
# that's what SQLAlchemy does (sic!)
self.proxy = QueryResultProxy(self.query).offset('1')
assert_equals(['bar', 'baz', 'quux', 'quuux'], self._names(self.proxy))
# --- iteration ------------------------------------------------------------
def test_can_iterate_over_results(self):
filter_ = lambda item: item.activity >= 2
self.proxy = QueryResultProxy(self.query, filter_=filter_)
assert_true(hasattr(self.proxy, '__iter__'))
results = list(self.proxy)
assert_equals(['baz', 'quux', 'quuux'], self._names(results))
# --- length ---------------------------------------------------------------
def test_can_tell_length_if_no_more_items_available(self):
filter_ = lambda item: item.activity >= 2
self.proxy = QueryResultProxy(self.query, filter_=filter_)
assert_true(hasattr(self.proxy, '__len__'))
assert_length(3, self.proxy.fetch(10))
assert_false(self.proxy.more_available())
assert_length(3, self.proxy)
def test_can_tell_length(self):
filter_ = lambda item: item.activity >= 2
self.proxy = QueryResultProxy(self.query, filter_=filter_)
assert_length(3, self.proxy)
def test_can_specify_how_many_items_should_be_fetched_by_default(self):
self.proxy = QueryResultProxy(self.query, default_fetch=3)
self.proxy.more_available()
assert_equals(3, len(self.proxy._prefetched_items))
# --- slicing --------------------------------------------------------------
def test_supports_simple_slicing(self):
assert_equals(['foo', 'bar'], self._names(self.proxy[0:2]))
# slicing does not consume items
assert_equals(['foo'], self._names([self.proxy.next()]))
assert_equals(['baz', 'quux', 'quuux'], self._names(self.proxy[2:5]))
