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