A simple example¶

Let’s say we have the following model:

class Toaster(object):

    def __init__(self, color, slots=2, content=None):
        self.color = color
        self.slots = slots
        self.content = content

    def __repr__(self):
        return "<Toaster '%s'>" % self.color


class User(object):

    def __init__(self, toasters):
        self.toasters = toasters

Let’s define a very simple fixtures YAML file:

toaster:   # The fixture's name
  fields:  # The fixture's content
    color: red
    slots: 5
    content: !rel toasts  # You can reference other fixtures
  model: charlatan.tests.fixtures.simple_models:Toaster

toaster_green:
  # Charlatan also supports inheritance
  inherit_from: toaster
  fields:
    color: green

toasts:
  # No model is defined, so it defaults to what `fields` actually is, i.e.
  # in our case, a list.
  fields:
    - "Toast 1"
    - "Toast 2"

In this example:

• toaster and toasts are the fixture keys.
• fields is provided as argument when instantiating the class: Toaster(**fields).
• model is the path to the model that we defined.
• !rel lets you create relationships by pointing to another fixture key.

You first need to load a fixtures file (do it once for the whole test suite) with charlatan.FixturesManager.load():

>>> import charlatan
>>> fixtures_manager = charlatan.FixturesManager()
>>> fixtures_manager.load("./docs/examples/simple_fixtures.yaml",
...     models_package="toaster.models")
>>> toaster = fixtures_manager.install_fixture("toaster")
>>> toaster.color
'red'
>>> toaster.slots
5
>>> toaster.content
['Toast 1', 'Toast 2']

Voila!

Factory features¶

Charlatan provides you with factory features. In particular, you can override a fixture’s defined attributes:

>>> toaster = fixtures_manager.install_fixture("toaster",
...     overrides={"color": "blue"})
>>> toaster.color
'blue'

You can also use inheritance:

>>> toaster = fixtures_manager.install_fixture("toaster_green")
>>> toaster.color
'green'

Using charlatan in test cases¶

Charlatan works best when used with unittest.TestCase. Your test class needs to inherit from charlatan.FixturesManagerMixin.

Charlatan uses an internal cache to store fixtures instance (in particular to create relationships). If you are resetting your database after each tests (using transactions or by manually truncating all tables), you need to clean the cache in TestCase.setUp(), otherwise Charlatan will try accessing objects that are not anymore in the sqlalchemy session.

import unittest

import charlatan

fixtures_manager = charlatan.FixturesManager()
fixtures_manager.load("./docs/examples/simple_fixtures.yaml")


class TestToaster(unittest.TestCase, charlatan.FixturesManagerMixin):

    def setUp(self):
        # Attach the fixtures manager to the instance
        self.fixtures_manager = fixtures_manager
        # Cleanup the cache
        self.init_fixtures()

    def test_example(self):
        """Verify that we can get fixtures."""
        toaster = self.install_fixture("toaster")
        self.assertEqual(toaster.color, "red")
        self.assertEqual(toaster.slots, 5)
        self.assertEqual(toaster.content, ['Toast 1', 'Toast 2'])

Using fixtures¶

There are multiple ways to require and use fixtures. When you install a fixture using the charlatan.FixturesManagerMixin, it gets attached to the instance and can be accessed as an instance attribute (e.g. self.toaster).

class MyTest(FixturesManagerMixin):

    def setUp(self):
        # This will create self.toaster and self.brioche
        self.install_fixtures(("toaster", "brioche"))

    def test_toaster(self):
        """Verify that a toaster toasts."""
        self.toaster.toast(self.brioche)

class MyTest(FixturesMixin):

    def test_toaster(self):
        self.install_fixture("toaster")

import pytest


@pytest.fixture
def get_fixture(request):
    request.addfinalizer(fixtures_manager.clean_cache)
    return fixtures_manager.get_fixture

def test_toaster(get_fixture):
    """Verify that a toaster toasts."""
    toaster = get_fixture('toaster')
    toast = get_fixture('toast')
    ...

class MyTest(FixturesManagerMixin):

    def test_toaster(self):
        self.toaster = self.get_fixture("toaster")
        self.toaster.brand = "Flying"
        self.toaster.save()

Defining a fixture¶

A fixture has an identifier (in the example above, toaster is one of the fixture identifiers), as well as the following configuration:

• fields: a dictionary for which keys are attribute, and values are their values
• model gives information about how to retrieve the model
• post_creation lets you have some attribute values be assigned after instantiation.

Inheritance¶

Fixtures can inherit from other fixtures.

first:
  fields:
    foo: bar

# Everything is inherited from first.
second:
  inherit_from: first

# You can add fields without removing existing ones
third:
  inherit_from: first
  fields:
    # foo: bar is implied by inheritance
    toaster: toasted

# You can also overwrite the model.
fourth:
  inherit_from: first
  model: collections:Counter

# You can also overwrite both.
fifth:
  inherit_from: second
  fields:
    toaster: toasted
  model: collections:Counter

>>> import pprint
>>> from charlatan import FixturesManager
>>> manager = FixturesManager()
>>> manager.load("docs/examples/fixtures_inheritance.yaml")
>>> manager.get_fixture("first")
{'foo': 'bar'}
>>> manager.get_fixture("second")
{'foo': 'bar'}
>>> pprint.pprint(manager.get_fixture("third"))
{'foo': 'bar', 'toaster': 'toasted'}
>>> fourth = manager.get_fixture("fourth")
>>> fourth
Counter({'foo': 'bar'})
>>> fourth.__class__.__name__
'Counter'
>>> fifth = manager.get_fixture("fifth")
>>> fifth
Counter({'toaster': 'toasted', 'foo': 'bar'})
>>> fifth.__class__.__name__
'Counter'

If your fields are dict, then the first-level key will override everything, unless you use deep_inherit:

toaster:
  fields:
    toasts:
      toast1:
        type: brioche
        price: 10
        weight: 20

toaster2:
  inherit_from: toaster
  deep_inherit: true
  fields:
    toasts:
      toast1:
        type: bread
        # Because of deep_inherit, the following fields are implied:
        # price: 10
        # weight: 20

Example test:

from charlatan import FixturesManager


def test_deep_inherit():
    manager = FixturesManager()
    manager.load('./charlatan/tests/example/data/deep_inherit.yaml')
    toaster2 = manager.get_fixture('toaster2')
    assert toaster2['toasts']['toast1']['price'] == 10
    assert toaster2['toasts']['toast1']['weight'] == 20

Having dictionaries as fixtures¶

If you don’t specify the model, the content of fields will be returned as is. This is useful if you want to enter a dictionary or a list directly.

fixture_name:
  fields:
    foo: bar

fixture_list:
  fields:
    - "foo"
    - "bar"

>>> manager = FixturesManager()
>>> manager.load("docs/examples/fixtures_dict.yaml")
>>> manager.get_fixture("fixture_name")
{'foo': 'bar'}
>>> manager.get_fixture("fixture_list")
['foo', 'bar']

Getting an already existing fixture from the database¶

You can also get a fixture directly from the database (it uses sqlalchemy): in this case, you just need to specify the model and an id.

toaster_already_in_db:
  id: 10
  model: Toaster

Dependencies¶

If a fixture depends on some side effect of another fixture, you can mark that dependency (and, necessarily, ordering) by using the depend_on section.

fixture1:
  fields:
    - name: "foo"

fixture2:
  depend_on:
    - fixture1
  fields:
    - name: "bar"
  post_creation:
    - some_descriptor_that_depend_on_fixture1: true

Post creation¶

Example:

user:
  fields:
    name: Michel Audiard
  model: User
  post_creation:
    has_used_toaster: true
    # Note that rel are allowed in post_creation
    new_toaster: !rel blue_toaster

For a given fixture, post_creation lets you change some attributes after instantiation. Here’s the pseudo-code:

instance = ObjectClass(**fields)
for k, v in post_creation:
    setattr(instance, k, v)

Linking to other objects¶

Example:

toaster:
  model: Toaster
  fields:
    color: red

user:
  model: User
  fields:
    # You can link to another fixture
    toasters:
      - !rel toaster

toaster_colors:
  # You can also link to a specific attribute
  fields:
    color: !rel toaster.color

To link to another object defined in the configuration file, use !rel. You can link to another objet (e.g. !rel toaster) or to another object’s attribute (e.g. !rel toaster.color).

>>> manager = FixturesManager()
>>> manager.load("docs/examples/relationships.yaml",
...     models_package="charlatan.tests.fixtures.simple_models")
>>> manager.get_fixture("user").toasters
[<Toaster 'red'>]
>>> manager.get_fixture("toaster_colors")
{'color': 'red'}

You can also link to specific attributes of collection’s item (see Collections of Fixtures for more information about collections).

toaster_colors_list:
  fields: ['red']

# Let's define a collection
toasters:
  model: Toaster
  objects:
    red:
      color: red

toaster_from_collection:
  inherit_from: toaster
  fields:
    # You can link a specific attribute of a collection's item.
    color: !rel toasters.red.color

>>> manager.get_fixture("toaster_from_collection")
<Toaster 'red'>

Collections of Fixtures¶

Charlatan also provides more efficient way to define variations of fixtures. The basic idea is to define the model and the default fields, then use the objects key to define related fixtures. There’s two ways to define those fixtures in the objects key:

• Use a list. You will then be able to access those fixtures via their index, e.g. toaster.0 for the first item.
• Use a dict. The key will be the name of the fixture, the value a dict of fields. You can access them via their namespace: e.g. toaster.blue.

You can also install all of them by installing the name of the collection.

toasters:
  model: charlatan.tests.fixtures.simple_models:Toaster

  # Those are the default for all fixtures
  fields:
    slots: 5

  # You can have named fixtures in the collection. Note the use of dict.
  objects:
    green:  # This fixture can be accessed via toaster.green
      color: green
    blue:
      color: blue

anonymous_toasters:
  inherit_from: toasters

  # Here we define unamed fixtures. Note that we use a list instead of a dict.
  objects:
    # You access the first fixture via anonymous_toaster.0
    -
      color: yellow
    -
      color: black

# Those collections can be used as is in relationships.

collection:
  fields:
    # Since we defined the toasters collection as a dict, things's value will
    # be a dict as well
    things: !rel toasters

users:
  model: charlatan.tests.fixtures.simple_models:User

  objects:

    1:
      toasters: !rel anonymous_toasters

    2:
      # You can also link to specific relationships using the namespace
      toasters: [!rel toasters.green]

    3:
      toasters: [!rel anonymous_toasters.0]

Here’s how you would use this fixture file to access specific fixtures:

>>> manager = FixturesManager()
>>> manager.load("docs/examples/collection.yaml")
>>> manager.get_fixture("toasters.green")
<Toaster 'green'>
>>> manager.get_fixture("anonymous_toasters.0")
<Toaster 'yellow'>

You can also access the whole collection:

>>> pprint.pprint(manager.get_fixture("toasters"))
{'blue': <Toaster 'blue'>, 'green': <Toaster 'green'>}
>>> manager.get_fixture("anonymous_toasters")
[<Toaster 'yellow'>, <Toaster 'black'>]

Like any fixture, this collection can be linked to in a relationship using the !rel keyword in an intuitive way.

>>> pprint.pprint(manager.get_fixture("collection"))
{'things': {'blue': <Toaster 'blue'>, 'green': <Toaster 'green'>}}
>>> user1 = manager.get_fixture("users.1")
>>> user1.toasters
[<Toaster 'yellow'>, <Toaster 'black'>]
>>> manager.get_fixture("users.2").toasters
[<Toaster 'green'>]
>>> manager.get_fixture("users.3").toasters
[<Toaster 'yellow'>]

Loading Fixtures from Multiple Files¶

Loading fixtures from multiple files works similarly to loading collections. In this case, every fixture in a single file is preceded by a namespace taken from the name of that file. Relationships between fixtures in different files specified using the !rel keyword may be specified by prefixing the desired target fixture with its file namespace.

toaster:
  model: Toaster
  fields:
    color: red

user:
  model: User
  fields:
    # You can link to another fixture
    toasters:
      - !rel toaster

toaster_colors:
  # You can also link to a specific attribute
  fields:
    color: !rel toaster.color

toaster_colors_list:
  fields: ['red']

# Let's define a collection
toasters:
  model: Toaster
  objects:
    red:
      color: red

toaster_from_collection:
  inherit_from: toaster
  fields:
    # You can link a specific attribute of a collection's item.
    color: !rel toasters.red.color

toaster:
  model: Toaster
  fields:
    color: !rel relationships.toaster.color

>>> manager = FixturesManager()
>>> manager.load(["docs/examples/relationships.yaml",
...     "docs/examples/files.yaml"],
...     models_package="charlatan.tests.fixtures.simple_models")
>>> manager.get_fixture("files.toaster")
<Toaster 'red'>

Datetime and timestamps¶

Use !now, which returns timezone-aware datetime. You can use modifiers, for instance:

• !now +1y returns the current datetime plus one year
• !now +5m returns the current datetime plus five months
• !now -10d returns the current datetime minus ten days
• !now +15M (note the case) returns the current datetime plus 15 minutes
• !now -30s returns the current datetime minus 30 seconds

For naive datetime (see the definition in Python’s datetime module documentation), use !now_naive. It also supports deltas.

For Unix timestamps (seconds since the epoch) you can use !epoch_now:

• !epoch_now +1d returns the current datetime plus one year in seconds since the epoch
• !epoch_now_in_ms returns the current timestamp in milliseconds

All the same time deltas work.

Unicode Strings¶

In python 2 strings are not, by default, loaded as unicode. To load all the strings from the yaml files as unicode strings, pass the option use_unicode as True when you instantiate your fixture manager.

SQLAlchemy¶

Charlatan has been heavily used and tested with sqlalchemy. Here’s a simple example:

Tests:

from charlatan import testing
from charlatan import FixturesManager
from charlatan.tests.fixtures.models import Session, Base, engine
from charlatan.tests.fixtures.models import Toaster

session = Session()
manager = FixturesManager(db_session=session)
manager.load("./charlatan/tests/example/data/sqlalchemy.yaml")


class TestSqlalchemyFixtures(testing.TestCase):

    def setUp(self):
        self.manager = manager

        # There's a lot of different patterns to setup and teardown the
        # database. This is the simplest possibility.
        Base.metadata.create_all(engine)

    def tearDown(self):
        Base.metadata.drop_all(engine)
        session.close()

    def test_double_install(self):
        """Verify that there's no double install."""
        self.manager.install_fixture('toaster')

        toaster = session.query(Toaster).one()
        assert toaster.color.name == 'red'

YAML file:

toaster:
  fields:
    color: !rel color
    name: "toaster1"
  model: charlatan.tests.fixtures.models:Toaster

color:
  fields:
    name: "red"
  model: charlatan.tests.fixtures.models:Color

Model definition:

from sqlalchemy import create_engine
from sqlalchemy import Column, Integer, String, ForeignKey
from sqlalchemy.orm import sessionmaker, relationship
from sqlalchemy.ext.declarative import declarative_base

Base = declarative_base()
engine = create_engine('sqlite:///:memory:')
Session = sessionmaker(bind=engine)


class Toaster(Base):

    __tablename__ = "toasters"

    id = Column(Integer, primary_key=True)
    name = Column(String)
    color_id = Column(String, ForeignKey('colors.name'))

    color = relationship("Color", backref='toasters')


class Color(Base):

    __tablename__ = "colors"

    id = Column(Integer, primary_key=True)
    name = Column(String)

Example¶

Here’s an example inspired by the schematics library, which expects a dict of attributes as a single instantiation argument:

from charlatan import FixturesManager
from charlatan.builder import Builder


class Toaster(object):

    def __init__(self, attrs):
        self.slots = attrs['slots']


class DictBuilder(Builder):

    def __call__(self, fixtures, klass, params, **kwargs):
        # A "normal" object would be instantiated this way:
        # return klass(**params)

        # Yet schematics object expect a dict of attributes as only argument.
        # So we'll do:
        return klass(params)


def test_custom_builder():
    manager = FixturesManager(get_builder=DictBuilder())
    manager.load('./charlatan/tests/example/data/custom_builder.yaml')
    assert manager.get_fixture('toaster').slots == 3

YAML file:

toaster:
  model: charlatan.tests.example.test_custom_builder:Toaster
  fields:
    slots: 3
    color: blue

API¶

class charlatan.builder.Builder¶

__call__(fixtures, klass, params, **kwargs)¶

Build a fixture.

Parameters:	fixtures (FixturesManager) – klass – the fixture’s class (model in the definition file) params – the fixture’s params (fields in the definition file) kwargs (dict) –

kwargs allows passing arguments to the builder to change its behavior.

class charlatan.builder.DeleteAndCommit¶

__call__(fixtures, instance, **kwargs)¶

delete(instance, session)¶

Delete instance.

class charlatan.builder.InstantiateAndSave¶

__call__(fixtures, klass, params, **kwargs)¶

Save a fixture instance.

If it’s a SQLAlchemy model, it will be added to the session and the session will be committed.

Otherwise, a save() method will be run if the instance has one. If it does not have one, nothing will happen.

Before and after the process, the before_save() and after_save() hook are run.

instantiate(klass, params)¶

Return instantiated instance.

save(instance, fixtures, session)¶

Save instance.

FixturesManager¶

class charlatan.FixturesManager(db_session=None, use_unicode=False, get_builder=None, delete_builder=None)¶

Manage Fixture objects.

Parameters:	db_session (Session) – sqlalchemy Session object use_unicode (bool) – get_builder (func) – delete_builder (func) –

New in version 0.4.0: get_builder and delete_builder arguments were added.

Deprecated since version 0.4.0: delete_instance, save_instance methods were deleted in favor of using builders.

New in version 0.3.0: db_session argument was added.

clean_cache()¶

Clean the cache.

delete_fixture(fixture_key, builder=None)¶

Delete a fixture instance.

Parameters:	fixture_key (str) – builder (func) –

Before and after the process, the before_delete() and after_delete() hook are run.

New in version 0.4.0: builder argument was added.

Deprecated since version 0.4.0: delete_instance method renamed to delete_fixture for consistency reason.

get_all_fixtures(builder=None)¶

Get all fixtures.

Parameters:	fixture_keys (iterable) –
Return type:	list of instantiated but unsaved fixtures

New in version 0.4.0: builder argument was added.

Deprecated since version 0.3.7: include_relationships argument was removed.

get_fixture(fixture_key, overrides=None, builder=None)¶

Return a fixture instance (but do not save it).

Parameters:	fixture_key (str) – overrides (dict) – override fields builder (func) – build builder.
Return type:	instantiated but unsaved fixture

New in version 0.4.0: builder argument was added. attrs argument renamed overrides.

Deprecated since version 0.4.0: do_not_save argument was removed.

Deprecated since version 0.3.7: include_relationships argument was removed.

get_fixtures(fixture_keys, builder=None)¶

Get fixtures from iterable.

Parameters:	fixture_keys (iterable) –
Return type:	list of instantiated but unsaved fixtures

New in version 0.4.0: builder argument was added.

Deprecated since version 0.3.7: include_relationships argument was removed.

get_hook(hook_name)¶

Return a hook.

Parameters:	hook_name (str) – e.g. before_delete.

install_all_fixtures()¶

Install all fixtures.

Return type:	list of fixture_instance

Deprecated since version 0.4.0: do_not_save argument was removed.

Deprecated since version 0.3.7: include_relationships argument was removed.

install_fixture(fixture_key, overrides=None)¶

Install a fixture.

Parameters:	fixture_key (str) – overrides (dict) – override fields
Return type:	fixture_instance

Deprecated since version 0.4.0: do_not_save argument was removed. attrs argument renamed overrides.

Deprecated since version 0.3.7: include_relationships argument was removed.

install_fixtures(fixture_keys)¶

Install a list of fixtures.

Parameters:	fixture_keys (str or list of strs) – fixtures to be installed
Return type:	list of fixture_instance

Deprecated since version 0.4.0: do_not_save argument was removed.

Deprecated since version 0.3.7: include_relationships argument was removed.

keys()¶

Return all fixture keys.

load(filenames, models_package='')¶

Pre-load the fixtures. Does not install anything.

Parameters:	filename (list_or_str) – file or list of files that holds the fixture data models_package (str) – package holding the models definition

Deprecated since version 0.3.0: db_session argument was removed and put in the object’s constructor arguments.

Changed in version 0.3.7: filename argument was changed to filenames, which can be list or string.

set_hook(hookname, func)¶

Add a hook.

Parameters:	hookname (str) – func (function) –

uninstall_all_fixtures()¶

Uninstall all installed fixtures.

Return type:	None

Deprecated since version 0.4.0: do_not_delete argument was removed. This function does not return anything.

uninstall_fixture(fixture_key)¶

Uninstall a fixture.

Parameters:	fixture_key (str) –
Return type:	None

Deprecated since version 0.4.0: do_not_delete argument was removed. This function does not return anything.

uninstall_fixtures(fixture_keys)¶

Uninstall a list of installed fixtures.

Parameters:	fixture_keys (str or list of strs) – fixtures to be uninstalled
Return type:	None

Deprecated since version 0.4.0: do_not_delete argument was removed. This function does not return anything.

FixturesManagerMixin¶

class charlatan.FixturesManagerMixin¶

Class from which test cases should inherit to use fixtures.

Changed in version 0.3.12: FixturesManagerMixin does not install class attributes fixtures anymore.

Changed in version 0.3.0: use_fixtures_manager method renamed init_fixtures.

Changed in version 0.3.0: Extensive change to the function signatures.

get_fixture(*args, **kwargs)¶

Return a fixture instance (but do not save it).

Parameters:	fixture_key (str) – overrides (dict) – override fields builder (func) – build builder.
Return type:	instantiated but unsaved fixture

New in version 0.4.0: builder argument was added. attrs argument renamed overrides.

Deprecated since version 0.4.0: do_not_save argument was removed.

Deprecated since version 0.3.7: include_relationships argument was removed.

get_fixtures(*args, **kwargs)¶

Get fixtures from iterable.

Parameters:	fixture_keys (iterable) –
Return type:	list of instantiated but unsaved fixtures

New in version 0.4.0: builder argument was added.

Deprecated since version 0.3.7: include_relationships argument was removed.

init_fixtures()¶

Initialize the fixtures.

This function must be called before doing anything else.

install_all_fixtures(*args, **kwargs)¶

Install all fixtures.

Return type:	list of fixture_instance

Deprecated since version 0.4.0: do_not_save argument was removed.

Deprecated since version 0.3.7: include_relationships argument was removed.

install_fixture(*args, **kwargs)¶

Install a fixture.

Parameters:	fixture_key (str) – overrides (dict) – override fields
Return type:	fixture_instance

Deprecated since version 0.4.0: do_not_save argument was removed. attrs argument renamed overrides.

Deprecated since version 0.3.7: include_relationships argument was removed.

install_fixtures(*args, **kwargs)¶

Install a list of fixtures.

Parameters:	fixture_keys (str or list of strs) – fixtures to be installed
Return type:	list of fixture_instance

Deprecated since version 0.4.0: do_not_save argument was removed.

Deprecated since version 0.3.7: include_relationships argument was removed.

uninstall_all_fixtures(*args, **kwargs)¶

Uninstall all installed fixtures.

Return type:	None

Deprecated since version 0.4.0: do_not_delete argument was removed. This function does not return anything.

uninstall_fixture(*args, **kwargs)¶

Uninstall a fixture.

Parameters:	fixture_key (str) –
Return type:	None

Deprecated since version 0.4.0: do_not_delete argument was removed. This function does not return anything.

uninstall_fixtures(*args, **kwargs)¶

Uninstall a list of installed fixtures.

Parameters:	fixture_keys (str or list of strs) – fixtures to be uninstalled
Return type:	None

Deprecated since version 0.4.0: do_not_delete argument was removed. This function does not return anything.

Fixture¶

class charlatan.Fixture(key, fixture_manager, model=None, fields=None, inherit_from=None, deep_inherit=False, post_creation=None, id_=None, models_package='', depend_on=frozenset([]))¶

Represent a fixture that can be installed.

static extract_rel_name(name)¶

Return the relationship and attr from an argument to !rel.

extract_relationships()¶

Return all dependencies.

Rtype generator:

Yields (depends_on, attr_name).

get_class()¶

Return class object for this instance.

get_instance(path=None, overrides=None, builder=None)¶

Instantiate the fixture using the model and return the instance.

Parameters:	path (str) – remaining path to return overrides (dict) – overriding fields builder (func) – function that is used to get the fixture

Deprecated since version 0.4.0: fields argument renamed overrides.

New in version 0.4.0: builder argument added.

Deprecated since version 0.3.7: include_relationships argument removed.

get_relationship(name)¶

Get a relationship and its attribute if necessary.

Utils¶

charlatan.utils.copy_docstring_from(klass)¶

Copy docstring from another class, using the same function name.

charlatan.utils.datetime_to_epoch_in_ms(a_datetime)¶

Return the epoch timestamp for the given datetime.

Parameters:	a_datetime (datetime) – The datetime to translate
Return type:	int

>>> a_datetime = datetime.datetime(2013, 11, 21, 1, 33, 11, 160611)
>>> datetime_to_epoch_timestamp(a_datetime)
1384997591.160611
>>> datetime_to_epoch_in_ms(a_datetime)
1384997591161

charlatan.utils.datetime_to_epoch_timestamp(a_datetime)¶

Return the epoch timestamp for the given datetime.

Parameters:	a_datetime (datetime) – The datetime to translate
Return type:	float

>>> a_datetime = datetime.datetime(2013, 11, 21, 1, 33, 11, 160611)
>>> datetime_to_epoch_timestamp(a_datetime)
1384997591.160611

charlatan.utils.deep_update(source, overrides)¶

Update a nested dictionary or similar mapping.

Modify source in place.

charlatan.utils.extended_timedelta(**kwargs)¶

Return a timedelta object based on the arguments.

Parameters:	years (integer) – months (integer) – days (integer) –
Return type:	timedelta instance

Since timedelta‘s largest unit are days, timedelta objects cannot be created with a number of months or years as an argument. This function lets you create timedelta objects based on a number of days, months and years.

>>> extended_timedelta(months=1)
datetime.timedelta(30)
>>> extended_timedelta(years=1)
datetime.timedelta(365)
>>> extended_timedelta(days=1, months=1, years=1)
datetime.timedelta(396)
>>> extended_timedelta(hours=1)
datetime.timedelta(0, 3600)

charlatan.utils.get_timedelta(delta)¶

Return timedelta from string.

Parameters:	delta (str) –
Return type:	datetime.timedelta instance

>>> get_timedelta("")
datetime.timedelta(0)
>>> get_timedelta("+1h")
datetime.timedelta(0, 3600)
>>> get_timedelta("+10h")
datetime.timedelta(0, 36000)
>>> get_timedelta("-10d")
datetime.timedelta(-10)
>>> get_timedelta("+1m")
datetime.timedelta(30)
>>> get_timedelta("-1y")
datetime.timedelta(-365)
>>> get_timedelta("+10d2h")
datetime.timedelta(10, 7200)
>>> get_timedelta("-10d2h")
datetime.timedelta(-11, 79200)
>>> get_timedelta("-21y2m1d24h")
datetime.timedelta(-7727)
>>> get_timedelta("+5M")
datetime.timedelta(0, 300)

charlatan.utils.is_sqlalchemy_model(instance)¶

Return True if instance is an SQLAlchemy model instance.

charlatan.utils.richgetter(obj, path)¶

Return a attrgetter + item getter.

charlatan.utils.safe_iteritems(items)¶

Safely iterate over a dict or a list.

0.4.6 (2015-09-22)¶

• Add support for epoch_now_in_ms (thanks to @chunyan)

0.4.5 (2015-05-29)¶

• Add deep_inherit to allow nested inheritance of fields.

0.4.4 (2015-05-28)¶

• Added !now_naive YAML file command to return naive datetime.

0.4.3 (2015-05-26)¶

• Fixed anonymous list objects name resolution (thanks to @jvrsantacruz)

0.4.2 (2015-05-19)¶

• Breaking change: the !now YAML command now returns timezone-aware datetime by default. You can change that behavior by changing charlatan.file_format.TIMEZONE_AWARE.
• Fixed bug where uninstalling a sqlalchemy fixture would not commit the delete to the session.
• Fixed bug where dict fixtures could not reference fields from other collections of dicts.

0.4.1 (2015-02-26)¶

• Fixed bug where !rel a_database_model.id, where id is a primary key generated by the database, would be None because of how fixtures are cached.
• Removed as_list and as_dict feature. It was unnecessarily complex and would not play well with caching fixtures.

0.4.0 (2015-02-18)¶

• Breaking change: get_builder and delete_builder arguments were added to charlatan.FixturesManager.
• Breaking change: delete_instance, save_instance methods were deleted in favor of using builders (see below).
• Breaking change: fields argument on charlatan.fixture.Fixture and fixtures collection class has been renamed overrides for consistency reasons.
• Breaking change: attrs argument on charlatan.FixturesManager been renamed overrides for consistency reasons.
• Breaking change: deleting fixtures will not return anything. It used to return the fixture or list of fixtures that were successfully deleted. It has been removed to apply the command query separation pattern. There are other ways to check which fixtures are installed, and hooks or builders can be used to customize deletion.
• Breaking change: do_not_save and do_not_delete arguments have been removed from all functions, in favor of using builders.
• The notion of charlatan.builder.Builder was added. This allows customizing how fixtures are instantiated and installed. A builder argument has been added to most method dealing with getting, installing or deleting fixtures. Sane defaults have been added in most places.
• Improve documentation about using pytest with charlatan.
• Fix bug preventing being able to load multiple fixtures file.

0.3.12 (2015-01-14)¶

• Do not install the class’ fixtures variable on charlatan.FixturesManagerMixin initialization. This can lead to bad pattern where a huge list of fixtures is installed for each test, even though each test uses only a few. Also, it’s safer to be explicit about this behavior and let the user have this automatic installation. Note that you can easily reimplement this behavior by subclassing or installing those in the class setUp method.

0.3.11 (2015-01-06)¶

• Fix getting relationships with fields that are nested more than one level

0.3.10 (2014-12-31)¶

• Get utcnow at fixture instantiation time, to allow using freezegun intuitively

0.3.9 (2014-11-13)¶

• Fix saving collection of fixtures to database (thanks to @joegilley)

0.3.8 (2014-08-19)¶

• Support loading of globbed filenames

0.3.7 (2014-07-07)¶

• Support loading of multiple fixtures files
• Remove include_relationships option in instance creation

0.3.6 (2014-06-02)¶

• Update PYYaml

0.3.5 (2014-06-02)¶

• Support loading all strings as unicode

0.3.4 (2014-01-21)¶

• Fix getting attribute from relationships

0.3.3 (2014-01-18)¶

• Add support for Python 3

0.3.2 (2014-01-16)¶

• Add ability to uninstall fixtures (thanks to @JordanB)

0.3.1 (2014-01-10)¶

• Numerous tests added, a lot of cleanup.
• Clarification in documentation.
• Remove load, set_hook and install_all_fixtures shortcuts from charlatan package.
• Remove FIXTURES_MANAGER singleton. Remove charlatan.fixtures_manager shortcut.
• Remove db_session argument to FixturesManager.load.
• Add db_session argument to FixturesManager constructor.
• Remove charlatan.fixtures_manager.FixturesMixin. Replaced by charlatan.testcase.FixturesManagerMixin.
• FixturesManagerMixin now exposes pretty much the same method as FixturesManager.
• FixturesManagerMixin‘s use_fixtures_manager was renamed init_fixtures.

0.2.9 (2013-11-20)¶

• Add !epoch_now for Unix timestamps (thanks to @erikformella)

0.2.8 (2013-11-12)¶

• Add ability to point to a list fixture (thanks to @erikformella)

0.2.7 (2013-10-24)¶

• Add ability to define dependencies outside of fields through the depend_on key in the yaml file (thanks to @Roguelazer)

0.2.6 (2013-09-06)¶

• Fix regression that broke API. install_fixture started returning the fixture as well as its name. (thanks to @erikformella)

0.2.5 (2013-09-06)¶

• Allow relationships to be used in dicts and lists. (thanks to @erikformella)
• Allow for seconds and minutes in relative timestamps (thanks to @kmnovak)

0.2.4 (2013-08-08)¶

• Empty models are allowed so that dict ands lists can be used as fixtures.
• Fixtures can now inherits from other fixtures.

0.2.3 (2013-06-28)¶

• Added ability to link to a relationship’s attribute in YAML file.
• Added ability to use !rel in post_creation.

0.1.2 (2013-04-01)¶

• Started tracking changes