tests: use unimported modules in test-demandimport.py

contextlib isn't a good module to test because it is likely already
imported by code above. Let's use modules that shouldn't have been
imported. And let's verify that with asserts.

Differential Revision: https://phab.mercurial-scm.org/D5797

tests/test-demandimport.py

@@ -1,224 +1,226 b''
 from __future__ import absolute_import, print_function
 
 from mercurial import demandimport
 demandimport.enable()
 
 import os
 import subprocess
 import sys
 import types
 
 # Don't import pycompat because it has too many side-effects.
 ispy3 = sys.version_info[0] >= 3
 
 # Only run if demandimport is allowed
 if subprocess.call(['python', '%s/hghave' % os.environ['TESTDIR'],
                     'demandimport']):
     sys.exit(80)
 
 # We rely on assert, which gets optimized out.
 if sys.flags.optimize:
     sys.exit(80)
 
 if ispy3:
     from importlib.util import _LazyModule
 
     try:
         from importlib.util import _Module as moduletype
     except ImportError:
         moduletype = types.ModuleType
 else:
     moduletype = types.ModuleType
 
 if os.name != 'nt':
     try:
         import distutils.msvc9compiler
         print('distutils.msvc9compiler needs to be an immediate '
               'importerror on non-windows platforms')
         distutils.msvc9compiler
     except ImportError:
         pass
 
 import re
 
 rsub = re.sub
 def f(obj):
     l = repr(obj)
     l = rsub("0x[0-9a-fA-F]+", "0x?", l)
     l = rsub("from '.*'", "from '?'", l)
     l = rsub("'<[a-z]*>'", "'<whatever>'", l)
     return l
 
 demandimport.disable()
 os.environ['HGDEMANDIMPORT'] = 'disable'
 # this enable call should not actually enable demandimport!
 demandimport.enable()
 from mercurial import node
 
 # We use assert instead of a unittest test case because having imports inside
 # functions changes behavior of the demand importer.
 if ispy3:
     assert not isinstance(node, _LazyModule)
 else:
     assert f(node) == "<module 'mercurial.node' from '?'>", f(node)
 
 # now enable it for real
 del os.environ['HGDEMANDIMPORT']
 demandimport.enable()
 
 # Test access to special attributes through demandmod proxy
 assert 'mercurial.error' not in sys.modules
 from mercurial import error as errorproxy
 
 if ispy3:
     # unsure why this isn't lazy.
     assert not isinstance(f, _LazyModule)
     assert f(errorproxy) == "<module 'mercurial.error' from '?'>", f(errorproxy)
 else:
     assert f(errorproxy) == "<unloaded module 'error'>", f(errorproxy)
 
 doc = ' '.join(errorproxy.__doc__.split()[:3])
 assert doc == 'Mercurial exceptions. This', doc
 assert errorproxy.__name__ == 'mercurial.error', errorproxy.__name__
 
 # __name__ must be accessible via __dict__ so the relative imports can be
 # resolved
 name = errorproxy.__dict__['__name__']
 assert name == 'mercurial.error', name
 
 if ispy3:
     assert not isinstance(errorproxy, _LazyModule)
     assert f(errorproxy) == "<module 'mercurial.error' from '?'>", f(errorproxy)
 else:
     assert f(errorproxy) == "<proxied module 'error'>", f(errorproxy)
 
 import os
 
 if ispy3:
     assert not isinstance(os, _LazyModule)
     assert f(os) == "<module 'os' from '?'>", f(os)
 else:
     assert f(os) == "<unloaded module 'os'>", f(os)
 
 assert f(os.system) == '<built-in function system>', f(os.system)
 assert f(os) == "<module 'os' from '?'>", f(os)
 
 assert 'mercurial.utils.procutil' not in sys.modules
 from mercurial.utils import procutil
 
 if ispy3:
     assert isinstance(procutil, _LazyModule)
     assert f(procutil) == "<module 'mercurial.utils.procutil' from '?'>", f(
         procutil
     )
 else:
     assert f(procutil) == "<unloaded module 'procutil'>", f(procutil)
 
 assert f(procutil.system) == '<function system at 0x?>', f(procutil.system)
 assert procutil.__class__ == moduletype, procutil.__class__
 assert f(procutil) == "<module 'mercurial.utils.procutil' from '?'>", f(
     procutil
 )
 assert f(procutil.system) == '<function system at 0x?>', f(procutil.system)
 
 assert 'mercurial.hgweb' not in sys.modules
 from mercurial import hgweb
 
 if ispy3:
     assert not isinstance(hgweb, _LazyModule)
     assert f(hgweb) == "<module 'mercurial.hgweb' from '?'>", f(hgweb)
     assert isinstance(hgweb.hgweb_mod, _LazyModule)
     assert (
         f(hgweb.hgweb_mod) == "<module 'mercurial.hgweb.hgweb_mod' from '?'>"
     ), f(hgweb.hgweb_mod)
 else:
     assert f(hgweb) == "<unloaded module 'hgweb'>", f(hgweb)
     assert f(hgweb.hgweb_mod) == "<unloaded module 'hgweb_mod'>", f(
         hgweb.hgweb_mod
     )
 
 assert f(hgweb) == "<module 'mercurial.hgweb' from '?'>", f(hgweb)
 
 import re as fred
 
 if ispy3:
     assert not isinstance(fred, _LazyModule)
     assert f(fred) == "<module 're' from '?'>"
 else:
     assert f(fred) == "<unloaded module 're'>", f(fred)
 
 import re as remod
 
 if ispy3:
     assert not isinstance(remod, _LazyModule)
     assert f(remod) == "<module 're' from '?'>"
 else:
     assert f(remod) == "<unloaded module 're'>", f(remod)
 
 import sys as re
 
 if ispy3:
     assert not isinstance(re, _LazyModule)
     assert f(re) == "<module 'sys' (built-in)>"
 else:
     assert f(re) == "<unloaded module 'sys'>", f(re)
 
 if ispy3:
     assert not isinstance(fred, _LazyModule)
     assert f(fred) == "<module 're' from '?'>", f(fred)
 else:
     assert f(fred) == "<unloaded module 're'>", f(fred)
 
 assert f(fred.sub) == '<function sub at 0x?>', f(fred.sub)
 
 if ispy3:
     assert not isinstance(fred, _LazyModule)
     assert f(fred) == "<module 're' from '?'>", f(fred)
 else:
     assert f(fred) == "<proxied module 're'>", f(fred)
 
 remod.escape  # use remod
 assert f(remod) == "<module 're' from '?'>", f(remod)
 
 if ispy3:
     assert not isinstance(re, _LazyModule)
     assert f(re) == "<module 'sys' (built-in)>"
     assert f(type(re.stderr)) == "<class '_io.TextIOWrapper'>", f(
         type(re.stderr)
     )
     assert f(re) == "<module 'sys' (built-in)>"
 else:
     assert f(re) == "<unloaded module 'sys'>", f(re)
     assert f(re.stderr) == "<open file '<whatever>', mode 'w' at 0x?>", f(
         re.stderr
     )
     assert f(re) == "<proxied module 'sys'>", f(re)
 
-import contextlib
+assert 'telnetlib' not in sys.modules
+import telnetlib
 
 if ispy3:
-    assert not isinstance(contextlib, _LazyModule)
-    assert f(contextlib) == "<module 'contextlib' from '?'>"
+    assert not isinstance(telnetlib, _LazyModule)
+    assert f(telnetlib) == "<module 'telnetlib' from '?'>"
 else:
-    assert f(contextlib) == "<unloaded module 'contextlib'>", f(contextlib)
+    assert f(telnetlib) == "<unloaded module 'telnetlib'>", f(telnetlib)
 
 try:
-    from contextlib import unknownattr
+    from telnetlib import unknownattr
 
     assert False, (
         'no demandmod should be created for attribute of non-package '
-        'module:\ncontextlib.unknownattr = %s' % f(unknownattr)
+        'module:\ntelnetlib.unknownattr = %s' % f(unknownattr)
     )
 except ImportError as inst:
     assert rsub(r"'", '', str(inst)).startswith(
         'cannot import name unknownattr'
     )
 
 from mercurial import util
 
 # Unlike the import statement, __import__() function should not raise
 # ImportError even if fromlist has an unknown item
 # (see Python/import.c:import_module_level() and ensure_fromlist())
-contextlibimp = __import__('contextlib', globals(), locals(), ['unknownattr'])
-assert f(contextlibimp) == "<module 'contextlib' from '?'>", f(contextlibimp)
-assert not util.safehasattr(contextlibimp, 'unknownattr')
+assert 'zipfile' not in sys.modules
+zipfileimp = __import__('zipfile', globals(), locals(), ['unknownattr'])
+assert f(zipfileimp) == "<module 'zipfile' from '?'>", f(zipfileimp)
+assert not util.safehasattr(zipfileimp, 'unknownattr')