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309 lines
9.6 KiB
Python
309 lines
9.6 KiB
Python
import unittest
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from test import support
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def funcattrs(**kwds):
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def decorate(func):
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func.__dict__.update(kwds)
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return func
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return decorate
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class MiscDecorators (object):
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@staticmethod
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def author(name):
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def decorate(func):
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func.__dict__['author'] = name
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return func
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return decorate
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# -----------------------------------------------
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class DbcheckError (Exception):
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def __init__(self, exprstr, func, args, kwds):
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# A real version of this would set attributes here
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Exception.__init__(self, "dbcheck %r failed (func=%s args=%s kwds=%s)" %
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(exprstr, func, args, kwds))
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def dbcheck(exprstr, globals=None, locals=None):
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"Decorator to implement debugging assertions"
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def decorate(func):
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expr = compile(exprstr, "dbcheck-%s" % func.__name__, "eval")
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def check(*args, **kwds):
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if not eval(expr, globals, locals):
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raise DbcheckError(exprstr, func, args, kwds)
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return func(*args, **kwds)
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return check
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return decorate
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# -----------------------------------------------
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def countcalls(counts):
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"Decorator to count calls to a function"
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def decorate(func):
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func_name = func.__name__
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counts[func_name] = 0
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def call(*args, **kwds):
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counts[func_name] += 1
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return func(*args, **kwds)
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call.__name__ = func_name
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return call
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return decorate
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# -----------------------------------------------
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def memoize(func):
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saved = {}
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def call(*args):
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try:
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return saved[args]
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except KeyError:
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res = func(*args)
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saved[args] = res
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return res
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except TypeError:
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# Unhashable argument
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return func(*args)
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call.__name__ = func.__name__
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return call
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# -----------------------------------------------
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class TestDecorators(unittest.TestCase):
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def test_single(self):
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class C(object):
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@staticmethod
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def foo(): return 42
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self.assertEqual(C.foo(), 42)
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self.assertEqual(C().foo(), 42)
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def test_staticmethod_function(self):
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@staticmethod
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def notamethod(x):
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return x
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self.assertRaises(TypeError, notamethod, 1)
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def test_dotted(self):
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decorators = MiscDecorators()
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@decorators.author('Cleese')
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def foo(): return 42
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self.assertEqual(foo(), 42)
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self.assertEqual(foo.author, 'Cleese')
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def test_argforms(self):
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# A few tests of argument passing, as we use restricted form
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# of expressions for decorators.
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def noteargs(*args, **kwds):
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def decorate(func):
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setattr(func, 'dbval', (args, kwds))
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return func
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return decorate
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args = ( 'Now', 'is', 'the', 'time' )
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kwds = dict(one=1, two=2)
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@noteargs(*args, **kwds)
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def f1(): return 42
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self.assertEqual(f1(), 42)
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self.assertEqual(f1.dbval, (args, kwds))
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@noteargs('terry', 'gilliam', eric='idle', john='cleese')
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def f2(): return 84
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self.assertEqual(f2(), 84)
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self.assertEqual(f2.dbval, (('terry', 'gilliam'),
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dict(eric='idle', john='cleese')))
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@noteargs(1, 2,)
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def f3(): pass
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self.assertEqual(f3.dbval, ((1, 2), {}))
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def test_dbcheck(self):
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@dbcheck('args[1] is not None')
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def f(a, b):
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return a + b
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self.assertEqual(f(1, 2), 3)
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self.assertRaises(DbcheckError, f, 1, None)
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def test_memoize(self):
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counts = {}
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@memoize
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@countcalls(counts)
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def double(x):
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return x * 2
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self.assertEqual(double.__name__, 'double')
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self.assertEqual(counts, dict(double=0))
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# Only the first call with a given argument bumps the call count:
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#
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self.assertEqual(double(2), 4)
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self.assertEqual(counts['double'], 1)
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self.assertEqual(double(2), 4)
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self.assertEqual(counts['double'], 1)
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self.assertEqual(double(3), 6)
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self.assertEqual(counts['double'], 2)
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# Unhashable arguments do not get memoized:
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#
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self.assertEqual(double([10]), [10, 10])
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self.assertEqual(counts['double'], 3)
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self.assertEqual(double([10]), [10, 10])
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self.assertEqual(counts['double'], 4)
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def test_errors(self):
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# Test syntax restrictions - these are all compile-time errors:
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#
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for expr in [ "1+2", "x[3]", "(1, 2)" ]:
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# Sanity check: is expr is a valid expression by itself?
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compile(expr, "testexpr", "exec")
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codestr = "@%s\ndef f(): pass" % expr
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self.assertRaises(SyntaxError, compile, codestr, "test", "exec")
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# You can't put multiple decorators on a single line:
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#
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self.assertRaises(SyntaxError, compile,
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"@f1 @f2\ndef f(): pass", "test", "exec")
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# Test runtime errors
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def unimp(func):
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raise NotImplementedError
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context = dict(nullval=None, unimp=unimp)
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for expr, exc in [ ("undef", NameError),
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("nullval", TypeError),
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("nullval.attr", AttributeError),
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("unimp", NotImplementedError)]:
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codestr = "@%s\ndef f(): pass\nassert f() is None" % expr
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code = compile(codestr, "test", "exec")
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self.assertRaises(exc, eval, code, context)
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def test_double(self):
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class C(object):
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@funcattrs(abc=1, xyz="haha")
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@funcattrs(booh=42)
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def foo(self): return 42
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self.assertEqual(C().foo(), 42)
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self.assertEqual(C.foo.abc, 1)
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self.assertEqual(C.foo.xyz, "haha")
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self.assertEqual(C.foo.booh, 42)
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def test_order(self):
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# Test that decorators are applied in the proper order to the function
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# they are decorating.
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def callnum(num):
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"""Decorator factory that returns a decorator that replaces the
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passed-in function with one that returns the value of 'num'"""
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def deco(func):
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return lambda: num
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return deco
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@callnum(2)
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@callnum(1)
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def foo(): return 42
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self.assertEqual(foo(), 2,
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"Application order of decorators is incorrect")
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def test_eval_order(self):
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# Evaluating a decorated function involves four steps for each
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# decorator-maker (the function that returns a decorator):
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#
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# 1: Evaluate the decorator-maker name
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# 2: Evaluate the decorator-maker arguments (if any)
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# 3: Call the decorator-maker to make a decorator
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# 4: Call the decorator
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#
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# When there are multiple decorators, these steps should be
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# performed in the above order for each decorator, but we should
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# iterate through the decorators in the reverse of the order they
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# appear in the source.
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actions = []
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def make_decorator(tag):
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actions.append('makedec' + tag)
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def decorate(func):
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actions.append('calldec' + tag)
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return func
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return decorate
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class NameLookupTracer (object):
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def __init__(self, index):
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self.index = index
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def __getattr__(self, fname):
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if fname == 'make_decorator':
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opname, res = ('evalname', make_decorator)
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elif fname == 'arg':
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opname, res = ('evalargs', str(self.index))
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else:
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assert False, "Unknown attrname %s" % fname
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actions.append('%s%d' % (opname, self.index))
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return res
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c1, c2, c3 = map(NameLookupTracer, [ 1, 2, 3 ])
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expected_actions = [ 'evalname1', 'evalargs1', 'makedec1',
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'evalname2', 'evalargs2', 'makedec2',
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'evalname3', 'evalargs3', 'makedec3',
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'calldec3', 'calldec2', 'calldec1' ]
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actions = []
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@c1.make_decorator(c1.arg)
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@c2.make_decorator(c2.arg)
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@c3.make_decorator(c3.arg)
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def foo(): return 42
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self.assertEqual(foo(), 42)
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self.assertEqual(actions, expected_actions)
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# Test the equivalence claim in chapter 7 of the reference manual.
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#
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actions = []
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def bar(): return 42
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bar = c1.make_decorator(c1.arg)(c2.make_decorator(c2.arg)(c3.make_decorator(c3.arg)(bar)))
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self.assertEqual(bar(), 42)
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self.assertEqual(actions, expected_actions)
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class TestClassDecorators(unittest.TestCase):
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def test_simple(self):
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def plain(x):
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x.extra = 'Hello'
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return x
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@plain
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class C(object): pass
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self.assertEqual(C.extra, 'Hello')
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def test_double(self):
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def ten(x):
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x.extra = 10
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return x
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def add_five(x):
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x.extra += 5
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return x
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@add_five
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@ten
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class C(object): pass
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self.assertEqual(C.extra, 15)
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def test_order(self):
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def applied_first(x):
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x.extra = 'first'
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return x
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def applied_second(x):
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x.extra = 'second'
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return x
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@applied_second
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@applied_first
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class C(object): pass
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self.assertEqual(C.extra, 'second')
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def test_main():
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support.run_unittest(TestDecorators)
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support.run_unittest(TestClassDecorators)
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if __name__=="__main__":
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test_main()
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