cpython/Lib/test/test_import.py

from test_support import TESTFN, TestFailed

import os
import random
import sys
import py_compile

# Brief digression to test that import is case-sensitive:  if we got this
# far, we know for sure that "random" exists.
try:
    import RAnDoM
except ImportError:
    pass
else:
    raise TestFailed("import of RAnDoM should have failed (case mismatch)")

# Another brief digression to test the accuracy of manifest float constants.
import double_const  # don't blink -- that *was* the test

def test_with_extension(ext): # ext normally ".py"; perhaps ".pyw"
    source = TESTFN + ext
    pyo = TESTFN + os.extsep + "pyo"
    if sys.platform.startswith('java'):
        pyc = TESTFN + "$py.class"
    else:
        pyc = TESTFN + os.extsep + "pyc"

    f = open(source, "w")
    print >> f, "# This tests Python's ability to import a", ext, "file."
    a = random.randrange(1000)
    b = random.randrange(1000)
    print >> f, "a =", a
    print >> f, "b =", b
    f.close()

    try:
        try:
            mod = __import__(TESTFN)
        except ImportError, err:
            raise ValueError("import from %s failed: %s" % (ext, err))

        if mod.a != a or mod.b != b:
            print a, "!=", mod.a
            print b, "!=", mod.b
            raise ValueError("module loaded (%s) but contents invalid" % mod)
    finally:
        os.unlink(source)

    try:
        try:
            reload(mod)
        except ImportError, err:
            raise ValueError("import from .pyc/.pyo failed: %s" % err)
    finally:
        try:
            os.unlink(pyc)
        except os.error:
            pass
        try:
            os.unlink(pyo)
        except os.error:
            pass
        del sys.modules[TESTFN]

sys.path.insert(0, os.curdir)
try:
    test_with_extension(os.extsep + "py")
    if sys.platform.startswith("win"):
        for ext in ".PY", ".Py", ".pY", ".pyw", ".PYW", ".pYw":
            test_with_extension(ext)
finally:
    del sys.path[0]

# Verify that the imp module can correctly load and find .py files
import imp
x = imp.find_module("os")
os = imp.load_module("os", *x)

def test_module_with_large_stack(module):
    # create module w/list of 65000 elements to test bug #561858
    filename = module + '.py'

    # create a file with a list of 65000 elements
    f = open(filename, 'w+')
    f.write('d = [\n')
    for i in range(65000):
        f.write('"",\n')
    f.write(']')
    f.close()

    # compile & remove .py file, we only need .pyc (or .pyo)
    f = open(filename, 'r')
    py_compile.compile(filename)
    f.close()
    os.unlink(filename)

    # need to be able to load from current dir
    sys.path.append('')

    # this used to crash
    exec 'import ' + module

    # cleanup
    del sys.path[-1]
    for ext in '.pyc', '.pyo':
        fname = module + ext
        if os.path.exists(fname):
            os.unlink(fname)

test_module_with_large_stack('longlist')