Home | History | Annotate | Download | only in test 
      1 """This module includes tests of the code object representation.
      2 
      3 >>> def f(x):
      4 ...     def g(y):
      5 ...         return x + y
      6 ...     return g
      7 ...
      8 
      9 >>> dump(f.func_code)
     10 name: f
     11 argcount: 1
     12 names: ()
     13 varnames: ('x', 'g')
     14 cellvars: ('x',)
     15 freevars: ()
     16 nlocals: 2
     17 flags: 3
     18 consts: ('None', '<code object g>')
     19 
     20 >>> dump(f(4).func_code)
     21 name: g
     22 argcount: 1
     23 names: ()
     24 varnames: ('y',)
     25 cellvars: ()
     26 freevars: ('x',)
     27 nlocals: 1
     28 flags: 19
     29 consts: ('None',)
     30 
     31 >>> def h(x, y):
     32 ...     a = x + y
     33 ...     b = x - y
     34 ...     c = a * b
     35 ...     return c
     36 ...
     37 >>> dump(h.func_code)
     38 name: h
     39 argcount: 2
     40 names: ()
     41 varnames: ('x', 'y', 'a', 'b', 'c')
     42 cellvars: ()
     43 freevars: ()
     44 nlocals: 5
     45 flags: 67
     46 consts: ('None',)
     47 
     48 >>> def attrs(obj):
     49 ...     print obj.attr1
     50 ...     print obj.attr2
     51 ...     print obj.attr3
     52 
     53 >>> dump(attrs.func_code)
     54 name: attrs
     55 argcount: 1
     56 names: ('attr1', 'attr2', 'attr3')
     57 varnames: ('obj',)
     58 cellvars: ()
     59 freevars: ()
     60 nlocals: 1
     61 flags: 67
     62 consts: ('None',)
     63 
     64 >>> def optimize_away():
     65 ...     'doc string'
     66 ...     'not a docstring'
     67 ...     53
     68 ...     53L
     69 
     70 >>> dump(optimize_away.func_code)
     71 name: optimize_away
     72 argcount: 0
     73 names: ()
     74 varnames: ()
     75 cellvars: ()
     76 freevars: ()
     77 nlocals: 0
     78 flags: 67
     79 consts: ("'doc string'", 'None')
     80 
     81 """
     82 
     83 import unittest
     84 import weakref
     85 from test.test_support import run_doctest, run_unittest, cpython_only
     86 
     87 
     88 def consts(t):
     89     """Yield a doctest-safe sequence of object reprs."""
     90     for elt in t:
     91         r = repr(elt)
     92         if r.startswith("<code object"):
     93             yield "<code object %s>" % elt.co_name
     94         else:
     95             yield r
     96 
     97 def dump(co):
     98     """Print out a text representation of a code object."""
     99     for attr in ["name", "argcount", "names", "varnames", "cellvars",
    100                  "freevars", "nlocals", "flags"]:
    101         print "%s: %s" % (attr, getattr(co, "co_" + attr))
    102     print "consts:", tuple(consts(co.co_consts))
    103 
    104 
    105 class CodeTest(unittest.TestCase):
    106 
    107     @cpython_only
    108     def test_newempty(self):
    109         import _testcapi
    110         co = _testcapi.code_newempty("filename", "funcname", 15)
    111         self.assertEqual(co.co_filename, "filename")
    112         self.assertEqual(co.co_name, "funcname")
    113         self.assertEqual(co.co_firstlineno, 15)
    114 
    115 
    116 def isinterned(s):
    117     return s is intern(('_' + s + '_')[1:-1])
    118 
    119 class CodeConstsTest(unittest.TestCase):
    120 
    121     def find_const(self, consts, value):
    122         for v in consts:
    123             if v == value:
    124                 return v
    125         self.assertIn(value, consts)  # raises an exception
    126         self.fail('Should never be reached')
    127 
    128     def assertIsInterned(self, s):
    129         if not isinterned(s):
    130             self.fail('String %r is not interned' % (s,))
    131 
    132     def assertIsNotInterned(self, s):
    133         if isinterned(s):
    134             self.fail('String %r is interned' % (s,))
    135 
    136     @cpython_only
    137     def test_interned_string(self):
    138         co = compile('res = "str_value"', '?', 'exec')
    139         v = self.find_const(co.co_consts, 'str_value')
    140         self.assertIsInterned(v)
    141 
    142     @cpython_only
    143     def test_interned_string_in_tuple(self):
    144         co = compile('res = ("str_value",)', '?', 'exec')
    145         v = self.find_const(co.co_consts, ('str_value',))
    146         self.assertIsInterned(v[0])
    147 
    148     @cpython_only
    149     def test_interned_string_default(self):
    150         def f(a='str_value'):
    151             return a
    152         self.assertIsInterned(f())
    153 
    154     @cpython_only
    155     def test_interned_string_with_null(self):
    156         co = compile(r'res = "str\0value!"', '?', 'exec')
    157         v = self.find_const(co.co_consts, 'str\0value!')
    158         self.assertIsNotInterned(v)
    159 
    160 
    161 class CodeWeakRefTest(unittest.TestCase):
    162 
    163     def test_basic(self):
    164         # Create a code object in a clean environment so that we know we have
    165         # the only reference to it left.
    166         namespace = {}
    167         exec "def f(): pass" in globals(), namespace
    168         f = namespace["f"]
    169         del namespace
    170 
    171         self.called = False
    172         def callback(code):
    173             self.called = True
    174 
    175         # f is now the last reference to the function, and through it, the code
    176         # object.  While we hold it, check that we can create a weakref and
    177         # deref it.  Then delete it, and check that the callback gets called and
    178         # the reference dies.
    179         coderef = weakref.ref(f.__code__, callback)
    180         self.assertTrue(bool(coderef()))
    181         del f
    182         self.assertFalse(bool(coderef()))
    183         self.assertTrue(self.called)
    184 
    185 
    186 def test_main(verbose=None):
    187     from test import test_code
    188     run_doctest(test_code, verbose)
    189     run_unittest(CodeTest, CodeConstsTest, CodeWeakRefTest)
    190 
    191 
    192 if __name__ == "__main__":
    193     test_main()
    194