implement and naively test the native traceback style

--HG--
branch : trunk

py/_code/code.py

@@ -354,9 +354,17 @@ class ExceptionInfo(object):
             abspath=False, tbfilter=True, funcargs=False):
         """ return str()able representation of this exception info.
             showlocals: show locals per traceback entry
-            style: long|short|no traceback style
+            style: long|short|no|native traceback style
             tbfilter: hide entries (where __tracebackhide__ is true)
         """
+        if style == 'native':
+            import traceback
+            return ''.join(traceback.format_exception(
+                self.type,
+                self.value,
+                self.traceback[0]._rawentry,
+                ))
+
         fmt = FormattedExcinfo(showlocals=showlocals, style=style,
             abspath=abspath, tbfilter=tbfilter, funcargs=funcargs)
         return fmt.repr_excinfo(self)

py/_plugin/pytest_terminal.py

@@ -22,7 +22,7 @@ def pytest_addoption(parser):
          help="(deprecated, use -r)")
     group._addoption('--tb', metavar="style",
                action="store", dest="tbstyle", default='long',
-               type="choice", choices=['long', 'short', 'no', 'line'],
+               type="choice", choices=['long', 'short', 'no', 'line', 'native'],
                help="traceback print mode (long/short/line/no).")
     group._addoption('--fulltrace',
                action="store_true", dest="fulltrace", default=False,

testing/code/test_excinfo.py

@@ -700,3 +700,12 @@ raise ValueError()
         repr = excinfo.getrepr(**reproptions)
         repr.toterminal(tw)
         assert tw.stringio.getvalue()
+
+
+    def test_native_style(self):
+        excinfo = self.excinfo_from_exec("""
+            assert 0
+        """)
+        repr = excinfo.getrepr(style='native')
+        assert repr.startswith('Traceback (most recent call last):\n  File')
+        assert repr.endswith('\n    assert 0\nAssertionError: assert 0\n')