MASTER

>>> f()
    () {}
    >>> f(1)
    (1,) {}
    >>> f(1, 2)
    (1, 2) {}
    >>> f(1, 2, 3)
    (1, 2, 3) {}
    >>> f(1, 2, 3, *(4, 5))
    (1, 2, 3, 4, 5) {}
    >>> f(1, 2, 3, *[4, 5])
    (1, 2, 3, 4, 5) {}
    >>> f(*[1, 2, 3], 4, 5)
    (1, 2, 3, 4, 5) {}
    >>> f(1, 2, 3, *UserList([4, 5]))
    (1, 2, 3, 4, 5) {}
    >>> f(1, 2, 3, *[4, 5], *[6, 7])
    (1, 2, 3, 4, 5, 6, 7) {}
    >>> f(1, *[2, 3], 4, *[5, 6], 7)
    (1, 2, 3, 4, 5, 6, 7) {}
    >>> f(*UserList([1, 2]), *UserList([3, 4]), 5, *UserList([6, 7]))
    (1, 2, 3, 4, 5, 6, 7) {}

Here we add keyword arguments

>>> f(1, 2, 3, **{'a':4, 'b':5})
    (1, 2, 3) {'a': 4, 'b': 5}
    >>> f(1, 2, **{'a': -1, 'b': 5}, **{'a': 4, 'c': 6})
    Traceback (most recent call last):
        ...
    TypeError: test.test_extcall.f() got multiple values for keyword argument 'a'
    >>> f(1, 2, **{'a': -1, 'b': 5}, a=4, c=6)
    Traceback (most recent call last):
        ...
    TypeError: test.test_extcall.f() got multiple values for keyword argument 'a'
    >>> f(1, 2, a=3, **{'a': 4}, **{'a': 5})
    Traceback (most recent call last):
        ...
    TypeError: test.test_extcall.f() got multiple values for keyword argument 'a'
    >>> f(1, 2, 3, *[4, 5], **{'a':6, 'b':7})
    (1, 2, 3, 4, 5) {'a': 6, 'b': 7}
    >>> f(1, 2, 3, x=4, y=5, *(6, 7), **{'a':8, 'b': 9})
    (1, 2, 3, 6, 7) {'a': 8, 'b': 9, 'x': 4, 'y': 5}
    >>> f(1, 2, 3, *[4, 5], **{'c': 8}, **{'a':6, 'b':7})
    (1, 2, 3, 4, 5) {'a': 6, 'b': 7, 'c': 8}
    >>> f(1, 2, 3, *(4, 5), x=6, y=7, **{'a':8, 'b': 9})
    (1, 2, 3, 4, 5) {'a': 8, 'b': 9, 'x': 6, 'y': 7}

>>> f(1, 2, 3, **UserDict(a=4, b=5))
    (1, 2, 3) {'a': 4, 'b': 5}
    >>> f(1, 2, 3, *(4, 5), **UserDict(a=6, b=7))
    (1, 2, 3, 4, 5) {'a': 6, 'b': 7}
    >>> f(1, 2, 3, x=4, y=5, *(6, 7), **UserDict(a=8, b=9))
    (1, 2, 3, 6, 7) {'a': 8, 'b': 9, 'x': 4, 'y': 5}
    >>> f(1, 2, 3, *(4, 5), x=6, y=7, **UserDict(a=8, b=9))
    (1, 2, 3, 4, 5) {'a': 8, 'b': 9, 'x': 6, 'y': 7}

Mix keyword arguments and dict unpacking

>>> d1 = {'a':1}

>>> d2 = {'c':3}

>>> f(b=2, **d1, **d2)
    () {'a': 1, 'b': 2, 'c': 3}

>>> f(**d1, b=2, **d2)
    () {'a': 1, 'b': 2, 'c': 3}

>>> f(**d1, **d2, b=2)
    () {'a': 1, 'b': 2, 'c': 3}

>>> f(**d1, b=2, **d2, d=4)
    () {'a': 1, 'b': 2, 'c': 3, 'd': 4}

Examples with invalid arguments (TypeErrors). We're also testing the function
names in the exception messages.

Verify clearing of SF bug #733667

>>> e(c=4)
    Traceback (most recent call last):
      ...
    TypeError: e() got an unexpected keyword argument 'c'

>>> g()
    Traceback (most recent call last):
      ...
    TypeError: g() missing 1 required positional argument: 'x'

>>> g(*())
    Traceback (most recent call last):
      ...
    TypeError: g() missing 1 required positional argument: 'x'

>>> g(*(), **{})
    Traceback (most recent call last):
      ...
    TypeError: g() missing 1 required positional argument: 'x'

>>> g(1)
    1 () {}
    >>> g(1, 2)
    1 (2,) {}
    >>> g(1, 2, 3)
    1 (2, 3) {}
    >>> g(1, 2, 3, *(4, 5))
    1 (2, 3, 4, 5) {}

>>> class Nothing: pass
    ...
    >>> g(*Nothing())
    Traceback (most recent call last):
      ...
    TypeError: test.test_extcall.g() argument after * must be an iterable, not Nothing

>>> class Nothing:
    ...     def __len__(self): return 5
    ...

>>> g(*Nothing())
    Traceback (most recent call last):
      ...
    TypeError: test.test_extcall.g() argument after * must be an iterable, not Nothing

>>> class Nothing():
    ...     def __len__(self): return 5
    ...     def __getitem__(self, i):
    ...         if i<3: return i
    ...         else: raise IndexError(i)
    ...

>>> g(*Nothing())
    0 (1, 2) {}

>>> class Nothing:
    ...     def __init__(self): self.c = 0
    ...     def __iter__(self): return self
    ...     def __next__(self):
    ...         if self.c == 4:
    ...             raise StopIteration
    ...         c = self.c
    ...         self.c += 1
    ...         return c
    ...

>>> g(*Nothing())
    0 (1, 2, 3) {}

Check for issue #4806: Does a TypeError in a generator get propagated with the
right error message? (Also check with other iterables.)

>>> def broken(): raise TypeError("myerror")
    ...

>>> g(*(broken() for i in range(1)))
    Traceback (most recent call last):
      ...
    TypeError: myerror
    >>> g(*range(1), *(broken() for i in range(1)))
    Traceback (most recent call last):
      ...
    TypeError: myerror

>>> class BrokenIterable1:
    ...     def __iter__(self):
    ...         raise TypeError('myerror')
    ...
    >>> g(*BrokenIterable1())
    Traceback (most recent call last):
      ...
    TypeError: myerror
    >>> g(*range(1), *BrokenIterable1())
    Traceback (most recent call last):
      ...
    TypeError: myerror

>>> class BrokenIterable2:
    ...     def __iter__(self):
    ...         yield 0
    ...         raise TypeError('myerror')
    ...
    >>> g(*BrokenIterable2())
    Traceback (most recent call last):
      ...
    TypeError: myerror
    >>> g(*range(1), *BrokenIterable2())
    Traceback (most recent call last):
      ...
    TypeError: myerror

>>> class BrokenSequence:
    ...     def __getitem__(self, idx):
    ...         raise TypeError('myerror')
    ...
    >>> g(*BrokenSequence())
    Traceback (most recent call last):
      ...
    TypeError: myerror
    >>> g(*range(1), *BrokenSequence())
    Traceback (most recent call last):
      ...
    TypeError: myerror

Make sure that the function doesn't stomp the dictionary

>>> d = {'a': 1, 'b': 2, 'c': 3}
    >>> d2 = d.copy()
    >>> g(1, d=4, **d)
    1 () {'a': 1, 'b': 2, 'c': 3, 'd': 4}
    >>> d == d2
    True

What about willful misconduct?

>>> def saboteur(**kw):
    ...     kw['x'] = 'm'
    ...     return kw

>>> d = {}
    >>> kw = saboteur(a=1, **d)
    >>> d
    {}

>>> g(1, 2, 3, **{'x': 4, 'y': 5})
    Traceback (most recent call last):
      ...
    TypeError: g() got multiple values for argument 'x'

>>> f(**{1:2})
    Traceback (most recent call last):
      ...
    TypeError: keywords must be strings

>>> h(**{'e': 2})
    Traceback (most recent call last):
      ...
    TypeError: h() got an unexpected keyword argument 'e'

>>> h(*h)
    Traceback (most recent call last):
      ...
    TypeError: test.test_extcall.h() argument after * must be an iterable, not function

>>> h(1, *h)
    Traceback (most recent call last):
      ...
    TypeError: Value after * must be an iterable, not function

>>> h(*[1], *h)
    Traceback (most recent call last):
      ...
    TypeError: Value after * must be an iterable, not function

>>> dir(*h)
    Traceback (most recent call last):
      ...
    TypeError: dir() argument after * must be an iterable, not function

>>> nothing = None
    >>> nothing(*h)
    Traceback (most recent call last):
      ...
    TypeError: None argument after * must be an iterable, \
not function

>>> h(**h)
    Traceback (most recent call last):
      ...
    TypeError: test.test_extcall.h() argument after ** must be a mapping, not function

>>> h(**[])
    Traceback (most recent call last):
      ...
    TypeError: test.test_extcall.h() argument after ** must be a mapping, not list

>>> h(a=1, **h)
    Traceback (most recent call last):
      ...
    TypeError: test.test_extcall.h() argument after ** must be a mapping, not function

>>> h(a=1, **[])
    Traceback (most recent call last):
      ...
    TypeError: test.test_extcall.h() argument after ** must be a mapping, not list

>>> h(**{'a': 1}, **h)
    Traceback (most recent call last):
      ...
    TypeError: test.test_extcall.h() argument after ** must be a mapping, not function

>>> h(**{'a': 1}, **[])
    Traceback (most recent call last):
      ...
    TypeError: test.test_extcall.h() argument after ** must be a mapping, not list

>>> dir(**h)
    Traceback (most recent call last):
      ...
    TypeError: dir() argument after ** must be a mapping, not function

>>> nothing(**h)
    Traceback (most recent call last):
      ...
    TypeError: None argument after ** must be a mapping, \
not function

>>> dir(b=1, **{'b': 1})
    Traceback (most recent call last):
      ...
    TypeError: dir() got multiple values for keyword argument 'b'

Test a kwargs mapping with duplicated keys.

>>> from collections.abc import Mapping
    >>> class MultiDict(Mapping):
    ...     def __init__(self, items):
    ...         self._items = items
    ...
    ...     def __iter__(self):
    ...         return (k for k, v in self._items)
    ...
    ...     def __getitem__(self, key):
    ...         for k, v in self._items:
    ...             if k == key:
    ...                 return v
    ...         raise KeyError(key)
    ...
    ...     def __len__(self):
    ...         return len(self._items)
    ...
    ...     def keys(self):
    ...         return [k for k, v in self._items]
    ...
    ...     def values(self):
    ...         return [v for k, v in self._items]
    ...
    ...     def items(self):
    ...         return [(k, v) for k, v in self._items]
    ...
    >>> g(**MultiDict([('x', 1), ('y', 2)]))
    1 () {'y': 2}

>>> g(**MultiDict([('x', 1), ('x', 2)]))
    Traceback (most recent call last):
      ...
    TypeError: test.test_extcall.g() got multiple values for keyword argument 'x'

>>> g(a=3, **MultiDict([('x', 1), ('x', 2)]))
    Traceback (most recent call last):
      ...
    TypeError: test.test_extcall.g() got multiple values for keyword argument 'x'

>>> g(**MultiDict([('a', 3)]), **MultiDict([('x', 1), ('x', 2)]))
    Traceback (most recent call last):
      ...
    TypeError: test.test_extcall.g() got multiple values for keyword argument 'x'

Another helper function

>>> def f2(*a, **b):
    ...     return a, b

>>> d = {}
    >>> for i in range(512):
    ...     key = 'k%d' % i
    ...     d[key] = i
    >>> a, b = f2(1, *(2,3), **d)
    >>> len(a), len(b), b == d
    (3, 512, True)

>>> class Foo:
    ...     def method(self, arg1, arg2):
    ...         return arg1+arg2

>>> x = Foo()
    >>> Foo.method(*(x, 1, 2))
    3
    >>> Foo.method(x, *(1, 2))
    3
    >>> Foo.method(*(1, 2, 3))
    5
    >>> Foo.method(1, *[2, 3])
    5

A PyCFunction that takes only positional parameters should allow an
empty keyword dictionary to pass without a complaint, but raise a
TypeError if te dictionary is not empty

>>> try:
    ...     silence = id(1, *{})
    ...     True
    ... except:
    ...     False
    True

>>> id(1, **{'foo': 1})
    Traceback (most recent call last):
      ...
    TypeError: id() takes no keyword arguments

A corner case of keyword dictionary items being deleted during
the function call setup. See <http://bugs.python.org/issue2016>.

>>> class Name(str):
    ...     def __eq__(self, other):
    ...         try:
    ...              del x[self]
    ...         except KeyError:
    ...              pass
    ...         return str.__eq__(self, other)
    ...     def __hash__(self):
    ...         return str.__hash__(self)

>>> x = {Name("a"):1, Name("b"):2}
    >>> def f(a, b):
    ...     print(a,b)
    >>> f(**x)
    1 2

Too many arguments:

>>> def f(): pass
    >>> f(1)
    Traceback (most recent call last):
      ...
    TypeError: f() takes 0 positional arguments but 1 was given
    >>> def f(a): pass
    >>> f(1, 2)
    Traceback (most recent call last):
      ...
    TypeError: f() takes 1 positional argument but 2 were given
    >>> def f(a, b=1): pass
    >>> f(1, 2, 3)
    Traceback (most recent call last):
      ...
    TypeError: f() takes from 1 to 2 positional arguments but 3 were given
    >>> def f(*, kw): pass
    >>> f(1, kw=3)
    Traceback (most recent call last):
      ...
    TypeError: f() takes 0 positional arguments but 1 positional argument (and 1 keyword-only argument) were given
    >>> def f(*, kw, b): pass
    >>> f(1, 2, 3, b=3, kw=3)
    Traceback (most recent call last):
      ...
    TypeError: f() takes 0 positional arguments but 3 positional arguments (and 2 keyword-only arguments) were given
    >>> def f(a, b=2, *, kw): pass
    >>> f(2, 3, 4, kw=4)
    Traceback (most recent call last):
      ...
    TypeError: f() takes from 1 to 2 positional arguments but 3 positional arguments (and 1 keyword-only argument) were given

Too few and missing arguments:

>>> def f(a): pass
    >>> f()
    Traceback (most recent call last):
      ...
    TypeError: f() missing 1 required positional argument: 'a'
    >>> def f(a, b): pass
    >>> f()
    Traceback (most recent call last):
      ...
    TypeError: f() missing 2 required positional arguments: 'a' and 'b'
    >>> def f(a, b, c): pass
    >>> f()
    Traceback (most recent call last):
      ...
    TypeError: f() missing 3 required positional arguments: 'a', 'b', and 'c'
    >>> def f(a, b, c, d, e): pass
    >>> f()
    Traceback (most recent call last):
      ...
    TypeError: f() missing 5 required positional arguments: 'a', 'b', 'c', 'd', and 'e'
    >>> def f(a, b=4, c=5, d=5): pass
    >>> f(c=12, b=9)
    Traceback (most recent call last):
      ...
    TypeError: f() missing 1 required positional argument: 'a'

Same with keyword only args:

>>> def f(*, w): pass
    >>> f()
    Traceback (most recent call last):
      ...
    TypeError: f() missing 1 required keyword-only argument: 'w'
    >>> def f(*, a, b, c, d, e): pass
    >>> f()
    Traceback (most recent call last):
      ...
    TypeError: f() missing 5 required keyword-only arguments: 'a', 'b', 'c', 'd', and 'e'

"""

import doctest
import unittest
from test import support

def load_tests(loader, tests, pattern):
    tests.addTest(doctest.DocTestSuite())
    return tests

if __name__ == '__main__':
    unittest.main()