incorrect regression tests
I found 7 regression tests which weren't being executed by regrtest. I checked in fixes for 6 of them. test_zipimport was the other test, but there was a problem. More on that below. To be run, tests must do one of following: 1) have a def test_main() which runs the tests 2) run the tests as a side-effect of import I'm wondering if regrtest.py should grow an option to print a list of all the tests which don't define test_main? When adding a new test, it will be easy to verify the test is, in fact, being run. Perhaps also a list of known tests which don't have a test_main and are expected to run on import? (I think there's over 100.) When test_zipimport is run by regrtest, there is memory corruption: [neal@epoch 2.3]$ ./python -E -tt ./Lib/test/regrtest.py test_zipimport test_zipimport Debug memory block at address p=0x40280508: 74 bytes originally requested The 4 pad bytes at p-4 are FORBIDDENBYTE, as expected. The 4 pad bytes at tail=0x40280552 are not all FORBIDDENBYTE (0xfb): at tail+0: 0x00 *** OUCH at tail+1: 0xfb at tail+2: 0xfb at tail+3: 0xfb The block was made by call #51959 to debug malloc/realloc. Data at p: 64 65 66 20 67 65 74 5f ... 69 6c 65 5f 5f 0a 00 0a Fatal Python error: bad trailing pad byte Aborted (core dumped) I didn't check in the test or investigate the cause. Below is a patch to the test so it will run under regrtest. Neal -- Index: test_zipimport.py =================================================================== RCS file: /cvsroot/python/python/dist/src/Lib/test/test_zipimport.py,v retrieving revision 1.5 diff -w -u -r1.5 test_zipimport.py --- test_zipimport.py 9 Jan 2003 22:27:10 -0000 1.5 +++ test_zipimport.py 17 Feb 2003 14:58:45 -0000 @@ -186,6 +186,9 @@ compression = ZIP_DEFLATED -if __name__ == "__main__": +def test_main(): test_support.run_unittest(UncompressedZipImportTestCase) test_support.run_unittest(CompressedZipImportTestCase) + +if __name__ == "__main__": + test_main()
[Neal Norwitz]
I found 7 regression tests which weren't being executed by regrtest. I checked in fixes for 6 of them.
Good catch!
test_zipimport was the other test, but there was a problem. More on that below.
Ditto.
To be run, tests must do one of following:
1) have a def test_main() which runs the tests 2) run the tests as a side-effect of import
New tests should do #1 (IMO). #2 means the import lock is held for the duration of the test, and that can create deadlock problems (indeed, I added the test_main() business to make it possible to run some thread tests reliably -- besides, it's always a mental strain when "big things" happen as a side effect).
I'm wondering if regrtest.py should grow an option to print a list of all the tests which don't define test_main? When adding a new test, it will be easy to verify the test is, in fact, being run. Perhaps also a list of known tests which don't have a test_main and are expected to run on import? (I think there's over 100.)
I'm not sure how this would help unless combined with a crusade to enforce that all tests have a test_main. Then regrtest could simply complain when there isn't one.
When test_zipimport is run by regrtest, there is memory corruption:
[neal@epoch 2.3]$ ./python -E -tt ./Lib/test/regrtest.py test_zipimport test_zipimport Debug memory block at address p=0x40280508: 74 bytes originally requested
That's an unusual # of bytes requested, because it's not divisible by 4. Best guess is that it's string memory.
The 4 pad bytes at p-4 are FORBIDDENBYTE, as expected. The 4 pad bytes at tail=0x40280552 are not all FORBIDDENBYTE (0xfb): at tail+0: 0x00 *** OUCH at tail+1: 0xfb at tail+2: 0xfb at tail+3: 0xfb
So code wrote \x00 into a single byte following the requested area: best guess now is that it's string memory and that whoever asked for it forgot to ask for room for a trailing 0 byte.
The block was made by call #51959 to debug malloc/realloc.
In obmalloc.c: """ /* serialno is always incremented via calling this routine. The point is to supply a single place to set a breakpoint. */ static void bumpserialno(void) { ++serialno; } """ If the test is deterministic, you can set a conditional breakpoint there for when serialno reaches 51959, and catch the offending malloc/realloc call in the act.
Data at p: 64 65 66 20 67 65 74 5f ... 69 6c 65 5f 5f 0a 00 0a
d e f g e t _ ... i l e _ _ \n \0 \n It's probably relevant that test_zipimport.py contains def get_file(): return __file__ in a string passed to compile() (and perhaps that Guido recently changed compile()).
participants (2)
-
Neal Norwitz -
Tim Peters