test_action_base_doctest.txt


..  _RefActionsDocTests:

Action doctests
****************************************************************************

ActionBase test suite
============================================================================

The :class:`ActionBase` class implements various basing behaviors of
action objects.


Test tool
----------------------------------------------------------------------------

The following PrintAction is used in this test suite::

    >>> from dragonfly import ActionBase, Repeat, Function
    >>> class PrintAction(ActionBase):
    ...     def __init__(self, name):
    ...         ActionBase.__init__(self)
    ...         self._name = name
    ...     def execute(self, data=None):
    ...         if data:
    ...             # Print a sorted representation of the data dict.
    ...             sorted_data = "{%s}" % ", ".join([
    ...                 "%r: %r" % (key, value)
    ...                 for key, value in sorted(data.items())
    ...             ])
    ...             print("executing %r %s" % (self._name, sorted_data))
    ...         else:
    ...              print("executing %r" % (self._name,))
    ...
    >>> a = PrintAction("a")
    >>> a.execute()
    executing 'a'
    >>> a.execute({"foo": 2})
    executing 'a' {'foo': 2}
    >>>


Concatenating actions
----------------------------------------------------------------------------

Concatenation of multiple actions::

    >>> b = PrintAction("b")
    >>> (a + b).execute()           # Simple concatenation.
    executing 'a'
    executing 'b'
    >>> (a + b).execute({"foo": 2}) # Simple concatenation.
    executing 'a' {'foo': 2}
    executing 'b' {'foo': 2}

    >>> c = a
    >>> c += b                      # In place concatenation.
    >>> c.execute({"foo": 2})
    executing 'a' {'foo': 2}
    executing 'b' {'foo': 2}
    >>> c += a                      # In place concatenation.
    >>> c.execute()
    executing 'a'
    executing 'b'
    executing 'a'

    >>> (c + c).execute()           # Same object concatenation.
    executing 'a'
    executing 'b'
    executing 'a'
    executing 'a'
    executing 'b'
    executing 'a'


Concatenating failing actions
----------------------------------------------------------------------------

Series execution normally stops if an action in the series fails::

    >>> bad_function = Function(lambda: 1/0)
    >>> # This will produce log messages about a ZeroDivisionError.
    >>> failing_series = (a + bad_function + b)
    >>> failing_series.execute()
    executing 'a'


Series execution will continue if 'stop_on_failures' is False::

    >>> failing_series.stop_on_failures = False
    >>> failing_series.execute()
    executing 'a'
    executing 'b'


Or if using the '|' or '\|\=' operators::

    >>> (a | bad_function | b).execute()
    executing 'a'
    executing 'b'
    >>> unsafe_action = a | b
    >>> unsafe_action |= bad_function
    >>> unsafe_action |= a
    >>> unsafe_action.execute()
    executing 'a'
    executing 'b'
    executing 'a'


Repeating actions
----------------------------------------------------------------------------

Actions can be repeated by multiplying them with a factor::

    >>> (a * 3).execute()
    executing 'a'
    executing 'a'
    executing 'a'
    >>> ((a + b) * 2).execute({"foo": 2})
    executing 'a' {'foo': 2}
    executing 'b' {'foo': 2}
    executing 'a' {'foo': 2}
    executing 'b' {'foo': 2}

    >>> factor = Repeat(3)              # Integer-factor repetition.
    >>> (a * factor).execute()
    executing 'a'
    executing 'a'
    executing 'a'
    >>> factor = Repeat(extra="foo")    # Named-factor repetition.
    >>> ((a + b) * factor).execute({"foo": 2})
    executing 'a' {'foo': 2}
    executing 'b' {'foo': 2}
    executing 'a' {'foo': 2}
    executing 'b' {'foo': 2}
    >>> ((a + b) * factor).execute({"bar": 2})
    Traceback (most recent call last):
      ...
    ActionError: No extra repeat factor found for name 'foo'

    >>> c = a
    >>> c.execute({"foo": 2})
    executing 'a' {'foo': 2}
    >>> c *= Repeat(extra="foo")
    >>> c.execute({"foo": 2})
    executing 'a' {'foo': 2}
    executing 'a' {'foo': 2}
    >>> c += b
    >>> c *= 2
    >>> c.execute({"foo": 1})
    executing 'a' {'foo': 1}
    executing 'b' {'foo': 1}
    executing 'a' {'foo': 1}
    executing 'b' {'foo': 1}
    >>> c *= 2
    >>> c.execute({"foo": 0})
    executing 'b' {'foo': 0}
    executing 'b' {'foo': 0}
    executing 'b' {'foo': 0}
    executing 'b' {'foo': 0}
    >>> c *= 0
    >>> c.execute({"foo": 1})


Binding data to actions
----------------------------------------------------------------------------

Binding of data to actions::

    >>> a_bound = a.bind({"foo": 2})
    >>> a_bound.execute()
    executing 'a' {'foo': 2}

    >>> b_bound = b.bind({"bar": 3})
    >>> b_bound.execute()
    executing 'b' {'bar': 3}

Earliest bound data is used during execution::

    >>> ab_bound = a_bound + b_bound
    >>> ab_bound.execute({"bar": "later"})
    executing 'a' {'bar': 'later', 'foo': 2}
    executing 'b' {'bar': 3}

    >>> ab_bound = (a_bound + b_bound).bind({"bar": "later"})
    >>> ab_bound.execute()
    executing 'a' {'bar': 'later', 'foo': 2}
    executing 'b' {'bar': 3}


Function action test suite
============================================================================

The :class:`Function` action wraps a callable, optionally with some
default keyword argument values.  On execution, the execution data
(commonly containing the recognition extras) are combined with the
default argument values (if present) to form the arguments with which
the callable will be called.


Using the Function action
----------------------------------------------------------------------------

Simple usage::
    >>> from dragonfly import Function
    >>> def func(count):
    ...     print("count: %d" % count)
    ...
    >>> action = Function(func)
    >>> action.execute({"count": 2})
    count: 2
    True
    >>> # Additional keyword arguments are ignored:
    >>> action.execute({"count": 2, "flavor": "vanilla"})
    count: 2
    True

Usage with default arguments::

    >>> def func(count, flavor):
    ...     print("count: %d" % count)
    ...     print("flavor: %s" % flavor)
    ...
    >>> # The Function object can be given default argument values:
    >>> action = Function(func, flavor="spearmint")
    >>> action.execute({"count": 2})
    count: 2
    flavor: spearmint
    True
    >>> # Arguments given at the execution-time to override default values:
    >>> action.execute({"count": 2, "flavor": "vanilla"})
    count: 2
    flavor: vanilla
    True

Usage with the ``remap_data`` argument::

    >>> def func(x, y, z):
    ...     print("x: %d" % x)
    ...     print("y: %d" % y)
    ...     print("z: %d" % z)
    ...
    >>> # The Function object can optionally be given a second dictionary
    >>> # argument to use extras with different names. It should be
    >>> # compatible with the 'defaults' parameter:
    >>> action = Function(func, dict(n="x", m="y"), z=4)
    >>> action.execute({"n": 2, "m": 3})
    x: 2
    y: 3
    z: 4
    True