Regressions in support for Python 3

Previous patch contained 1 needless change.

Thank you for the patch. Sadly we've let this happen for the tag support too, I'm fixing that up as a separate bug.

Results for revision 169:

$ python3.2 -m testtools.run subunit.test_suite
Tests running...
======================================================================
ERROR: subunit.tests.test_subunit_filter.TestFilterCommand.test_default
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/tmp/subunit/python/subunit/tests/test_subunit_filter.py", line 323, in test_default
    "test: foo\n"
  File "/tmp/subunit/python/subunit/tests/test_subunit_filter.py", line 310, in run_command
    out, err = ps.communicate(stream)
  File "/usr/lib64/python3.2/subprocess.py", line 819, in communicate
    return self._communicate(input)
  File "/usr/lib64/python3.2/subprocess.py", line 1435, in _communicate
    stdout, stderr = self._communicate_with_poll(input)
  File "/usr/lib64/python3.2/subprocess.py", line 1502, in _communicate_with_poll
    input_offset += os.write(fd, chunk)
TypeError: 'str' does not support the buffer interface
======================================================================
ERROR: subunit.tests.test_subunit_filter.TestFilterCommand.test_tags
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/tmp/subunit/python/subunit/tests/test_subunit_filter.py", line 336, in test_tags
    "tags: a\n"
  File "/tmp/subunit/python/subunit/tests/test_subunit_filter.py", line 310, in run_command
    out, err = ps.communicate(stream)
  File "/usr/lib64/python3.2/subprocess.py", line 819, in communicate
    return self._communicate(input)
  File "/usr/lib64/python3.2/subprocess.py", line 1435, in _communicate
    stdout, stderr = self._communicate_with_poll(input)
  File "/usr/lib64/python3.2/subprocess.py", line 1502, in _communicate_with_poll
    input_offset += os.write(fd, chunk)
TypeError: 'str' does not support the buffer interface
======================================================================
ERROR: subunit.tests.test_subunit_filter.TestTestResultFilter.test_tags_tracked_correctly
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/tmp/subunit/python/subunit/tests/test_subunit_filter.py", line 107, in test_tags_tracked_correctly
    self.run_tests(result_filter, input_stream)
  File "/tmp/subunit/python/subunit/tests/test_subunit_filter.py", line 67, in run_tests
    test = subunit.ProtocolTestCase(BytesIO(input_stream))
TypeError: 'str' does not support the buffer interface
======================================================================
FAIL: subunit.tests.test_subunit_filter.TestTestResultFilter.test_tag_filter
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/tmp/subunit/python/subunit/tests/test_subunit_filter.py", line 94, in test_tag_filter
    self.assertEquals(tests_expected, tests_included)
testtools.matchers.MismatchError: !=:
reference = <map object at 0x245da50>
actual = [<subunit.RemotedTestCase description='passed'>,
 <subunit.RemotedTestCase description='error'>,
 <subunit.RemotedTestCase description='skipped'>,
 <subunit.RemotedTestCase description='todo'>]

Ra...

Revision 170 has been just committed. With this revision, test suite passes with Python 3.2, but still fails with 3.1:

$ python3.1 -m testtools.run subunit.test_suite
Tests running...
======================================================================
ERROR: subunit.tests.test_subunit_filter.TestFilterCommand.test_default
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/tmp/subunit/python/subunit/tests/test_subunit_filter.py", line 323, in test_default
    "test: foo\n"
  File "/tmp/subunit/python/subunit/tests/test_subunit_filter.py", line 312, in run_command
    raise RuntimeError("%s failed: %s" % (command, err))
RuntimeError: ['/usr/bin/python3.1', '/tmp/subunit/filters/subunit-filter'] failed: b'Traceback (most recent call last):\n File "/tmp/subunit/filters/subunit-filter", line 158, in <module>\n main()\n File "/tmp/subunit/filters/subunit-filter", line 153, in main\n forward=False)\n File "/tmp/subunit/python/subunit/filters.py", line 92, in filter_by_result\n result = result_factory(output_to)\n File "/tmp/subunit/filters/subunit-filter", line 150, in <lambda>\n lambda output_to: _make_result(sys.stdout, options, filter_predicate),\n File "/tmp/subunit/filters/subunit-filter", line 130, in _make_result\n TestProtocolClient(output),\n File "/tmp/subunit/python/subunit/__init__.py", line 614, in __init__\n stream = _make_stream_binary(stream)\n File "/tmp/subunit/python/subunit/__init__.py", line 1267, in _make_stream_binary\n return _unwrap_text(stream)\n File "/tmp/subunit/python/subunit/__init__.py", line 1281, in _unwrap_text\n if type(stream.read(0)) is str:\nIOError: not readable\n'
======================================================================
ERROR: subunit.tests.test_subunit_filter.TestFilterCommand.test_tags
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/tmp/subunit/python/subunit/tests/test_subunit_filter.py", line 336, in test_tags
    "tags: a\n"
  File "/tmp/subunit/python/subunit/tests/test_subunit_filter.py", line 312, in run_command
    raise RuntimeError("%s failed: %s" % (command, err))
RuntimeError: ['/usr/bin/python3.1', '/tmp/subunit/filters/subunit-filter', '-s', '--with-tag', 'a'] failed: b'Traceback (most recent call last):\n File "/tmp/subunit/filters/subunit-filter", line 158, in <module>\n main()\n File "/tmp/subunit/filters/subunit-filter", line 153, in main\n forward=False)\n File "/tmp/subunit/python/subunit/filters.py", line 92, in filter_by_result\n result = result_factory(output_to)\n File "/tmp/subunit/filters/subunit-filter", line 150, in <lambda>\n lambda output_to: _make_result(sys.stdout, options, filter_predicate),\n File "/tmp/subunit/filters/subunit-filter", line 130, in _make_result\n TestProtocolClient(output),\n File "/tmp/subunit/python/subunit/__init__.py", line 614, in __init__\n stream = _make_stream_binary(stream)\n File "/tmp/subunit/python/subunit/__init__.py", line 1267, in _make_stream_binary\n return _unwrap_text(stream)\n File "/tmp/subunit/python/subunit/__init__.py", line 128...

The exceptions are different:

$ python3.1 -c 'open("/dev/null", "w").read()'
 Traceback (most recent call last):
   File "<string>", line 1, in <module>
 IOError: not readable
 $ python3.2 -c 'open("/dev/null", "w").read()'
 Traceback (most recent call last):
   File "<string>", line 1, in <module>
 io.UnsupportedOperation: not readable

The following fix works, but maybe _UnsupportedOperation should be changed.

--- python/subunit/__init__.py
 +++ python/subunit/__init__.py
 @@ -1280,7 +1280,7 @@
              # Read streams
              if type(stream.read(0)) is str:
                  return stream.buffer
 - except _UnsupportedOperation:
 + except (_UnsupportedOperation, IOError):
              # Cannot read from the stream: try via writes
              try:
                  stream.write(_b(''))

Thanks, will commit that.

(Also, I really appreciate your rapid testing!)

Actually 'except IOError:' would suffice, since io.UnsupportedOperation is a subclass of IOError.

$ python3.1 -c 'import io; print(issubclass(io.UnsupportedOperation, IOError))'
True
$ python3.2 -c 'import io; print(issubclass(io.UnsupportedOperation, IOError))'
True