summaryrefslogtreecommitdiff
path: root/lib/python2.7/test/test_decorators.py
diff options
context:
space:
mode:
Diffstat (limited to 'lib/python2.7/test/test_decorators.py')
-rw-r--r--lib/python2.7/test/test_decorators.py309
1 files changed, 309 insertions, 0 deletions
diff --git a/lib/python2.7/test/test_decorators.py b/lib/python2.7/test/test_decorators.py
new file mode 100644
index 0000000..cf2bc30
--- /dev/null
+++ b/lib/python2.7/test/test_decorators.py
@@ -0,0 +1,309 @@
+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()
generated by cgit v1.2.3 (git 2.25.1) at 2024-06-06 14:33:22 +0000