fix issue364: shorten and enhance tracebacks representation by default.

The new "--tb=auto" option (default) will only display long tracebacks
for the first and last entry.  You can get the old behaviour of printing
all entries as long entries with "--tb=long".  Also short entries by
default are now printed very similarly to "--tb=native" ones.

CHANGELOG

@@ -1,6 +1,12 @@
 NEXT (2.6)
 -----------------------------------
 
+- fix issue364: shorten and enhance tracebacks representation by default.  
+  The new "--tb=auto" option (default) will only display long tracebacks
+  for the first and last entry.  You can get the old behaviour of printing
+  all entries as long entries with "--tb=long".  Also short entries by
+  default are now printed very similarly to "--tb=native" ones.
+
 - fix issue514: teach assertion reinterpretation about private class attributes
 
 - change -v output to include full node IDs of tests.  Users can copy

_pytest/__init__.py

@@ -1,2 +1,2 @@
 #
-__version__ = '2.6.0.dev1'
+__version__ = '2.6.0.dev2'

_pytest/main.py

@@ -390,20 +390,24 @@ class Node(object):
         fm = self.session._fixturemanager
         if excinfo.errisinstance(fm.FixtureLookupError):
             return excinfo.value.formatrepr()
+        tbfilter = True
         if self.config.option.fulltrace:
             style="long"
         else:
             self._prunetraceback(excinfo)
-        # XXX should excinfo.getrepr record all data and toterminal()
+            tbfilter = False  # prunetraceback already does it
-        # process it?
+            if style == "auto":
+                style = "long"
+        # XXX should excinfo.getrepr record all data and toterminal() process it?
         if style is None:
             if self.config.option.tbstyle == "short":
                 style = "short"
             else:
                 style = "long"
+
         return excinfo.getrepr(funcargs=True,
                                showlocals=self.config.option.showlocals,
-                               style=style)
+                               style=style, tbfilter=tbfilter)
 
     repr_failure = _repr_failure_py
 

_pytest/python.py

@@ -578,6 +578,12 @@ class FunctionMixin(PyobjMixin):
                 if ntraceback == traceback:
                     ntraceback = ntraceback.cut(excludepath=cutdir)
             excinfo.traceback = ntraceback.filter()
+            # issue364: mark all but first and last frames to
+            # only show a single-line message for each frame
+            if self.config.option.tbstyle == "auto":
+                if len(excinfo.traceback) > 2:
+                    for entry in excinfo.traceback[1:-1]:
+                        entry.set_repr_style('short')
 
     def _repr_failure_py(self, excinfo, style="long"):
         if excinfo.errisinstance(pytest.fail.Exception):
@@ -588,8 +594,10 @@ class FunctionMixin(PyobjMixin):
 
     def repr_failure(self, excinfo, outerr=None):
         assert outerr is None, "XXX outerr usage is deprecated"
-        return self._repr_failure_py(excinfo,
+        style = self.config.option.tbstyle
-            style=self.config.option.tbstyle)
+        if style == "auto":
+            style = "long"
+        return self._repr_failure_py(excinfo, style=style)
 
 
 class Generator(FunctionMixin, PyCollector):

_pytest/terminal.py

@@ -23,8 +23,8 @@ def pytest_addoption(parser):
          action="store", dest="report", default=None, metavar="opts",
          help="(deprecated, use -r)")
     group._addoption('--tb', metavar="style",
-               action="store", dest="tbstyle", default='long',
+               action="store", dest="tbstyle", default='auto',
-               choices=['long', 'short', 'no', 'line', 'native'],
+               choices=['auto', 'long', 'short', 'no', 'line', 'native'],
                help="traceback print mode (long/short/line/native/no).")
     group._addoption('--fulltrace', '--full-trace',
                action="store_true", default=False,

setup.py

@@ -17,7 +17,7 @@ long_description = open('README.rst').read()
 
 
 def main():
-    install_requires = ['py>=1.4.20']
+    install_requires = ['py>=1.4.21.dev2']
     if sys.version_info < (2, 7) or (3,) <= sys.version_info < (3, 2):
         install_requires.append('argparse')
     if sys.platform == 'win32':
@@ -27,7 +27,7 @@ def main():
         name='pytest',
         description='pytest: simple powerful testing with Python',
         long_description=long_description,
-        version='2.6.0.dev1',
+        version='2.6.0.dev2',
         url='http://pytest.org',
         license='MIT license',
         platforms=['unix', 'linux', 'osx', 'cygwin', 'win32'],

testing/python/collect.py

@@ -641,7 +641,7 @@ class TestTracebackCutting:
         assert "x = 1" not in out
         assert "x = 2" not in out
         result.stdout.fnmatch_lines([
-            ">*asd*",
+            " *asd*",
             "E*NameError*",
         ])
         result = testdir.runpytest("--fulltrace")

testing/test_assertion.py

@@ -369,7 +369,7 @@ def test_traceback_failure(testdir):
         def test_onefails():
             f(3)
     """)
-    result = testdir.runpytest(p1)
+    result = testdir.runpytest(p1, "--tb=long")
     result.stdout.fnmatch_lines([
         "*test_traceback_failure.py F",
         "====* FAILURES *====",
@@ -389,6 +389,25 @@ def test_traceback_failure(testdir):
         "*test_traceback_failure.py:4: AssertionError"
     ])
 
+    result = testdir.runpytest(p1) # "auto"
+    result.stdout.fnmatch_lines([
+        "*test_traceback_failure.py F",
+        "====* FAILURES *====",
+        "____*____",
+        "",
+        "    def test_onefails():",
+        ">       f(3)",
+        "",
+        "*test_*.py:6: ",
+        "",
+        "    def f(x):",
+        ">       assert x == g()",
+        "E       assert 3 == 2",
+        "E        +  where 2 = g()",
+        "",
+        "*test_traceback_failure.py:4: AssertionError"
+    ])
+
 @pytest.mark.skipif("sys.version_info < (2,5) or '__pypy__' in sys.builtin_module_names or sys.platform.startswith('java')" )
 def test_warn_missing(testdir):
     testdir.makepyfile("")

testing/test_terminal.py

@@ -559,8 +559,8 @@ def test_tbstyle_short(testdir):
     assert 'x = 0' not in s
     result.stdout.fnmatch_lines([
         "*%s:5*" % p.basename,
-        ">*assert x",
+        "    assert x",
-        "E*assert*",
+        "E   assert*",
     ])
     result = testdir.runpytest()
     s = result.stdout.str()
@@ -583,7 +583,7 @@ class TestGenericReporting:
         testdir.makepyfile("import xyz\n")
         result = testdir.runpytest(*option.args)
         result.stdout.fnmatch_lines([
-            ">   import xyz",
+            "?   import xyz",
             "E   ImportError: No module named *xyz*",
             "*1 error*",
         ])