Created
September 9, 2014 07:40
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class ArgumentConversionException(Exception): | |
pass | |
def _validate(args, conversions): | |
args_len, conversions_len = len(args), len(conversions) | |
msg = None | |
if args_len < conversions_len: | |
msg = ('Too many conversion functions given: %d arguments given when ' | |
'%d conversions got.' % (args_len, conversions_len)) | |
if args_len > conversions_len: | |
msg = ('Not enough conversion function given: %d arguments given when ' | |
'%d conversion got.' % (args_len, conversions_len)) | |
for conv in conversions: | |
if conv == None: | |
continue | |
if not hasattr(conv, '__call__'): | |
msg = ('Given conversion function "%s" is not a callable. Is it a ' | |
'function?' % str(conv)) | |
break | |
if msg: | |
raise ArgumentConversionException(msg) | |
def convert_arguments(*conversions): | |
def outer(func): | |
def inner(self, *args, **kwargs): | |
_validate(args, conversions) | |
converted_args = [] | |
for arg, conv in zip(args, conversions): | |
if not conv: | |
converted_args.append(arg) | |
continue | |
converted_args.append(conv(arg)) | |
return func(self, *converted_args, **kwargs) | |
return inner | |
return outer | |
if __name__ == '__main__': | |
class test(object): | |
@convert_arguments(int, int) | |
def test_basic_case(self, a, b): | |
return a,b | |
@convert_arguments(int, None, int) | |
def test_skipping_arguments(self, a, b, c): | |
return a, b, c | |
@convert_arguments(int) | |
def test_too_few_conversions(self, a, b): | |
return a, b | |
@convert_arguments(int, None) | |
def test_too_many_conversions(self, a): | |
return a | |
@convert_arguments(int, object()) | |
def test_invalid_conversion_functions(self, a, b): | |
return a,b | |
t = test() | |
a1, a2 = t.test_basic_case('1', '2') | |
assert isinstance(a1, int) and isinstance(a2, int) | |
a1, a2, a3 = t.test_skipping_arguments('1', 'asd', '2') | |
assert (isinstance(a1, int) and isinstance(a2, basestring) and | |
isinstance(a3, int)) | |
try: | |
a1, a2 = t.test_too_few_conversions('1', '2') | |
raise AssertionError('Should have failed.') | |
except ArgumentConversionException: | |
pass | |
try: | |
a1 = t.test_too_many_conversions('1') | |
raise AssertionError('Should have failed.') | |
except ArgumentConversionException: | |
pass | |
try: | |
a1, a2 = t.test_invalid_conversion_functions('1', '2') | |
raise AssertionError('Should have failed.') | |
except ArgumentConversionException: | |
pass |
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