merge almarklein/default

CHANGELOG

@@ -62,6 +62,10 @@
 
 - fix issue463: raise specific error for 'parameterize' misspelling (pfctdayelise).
 
+- On failure, the ``sys.last_value``, ``sys.last_type`` and
+  ``sys.last_traceback`` are set, so that a user can inspect the error
+  via postmortem debugging (almarklein).
+
 2.6.4
 ----------
 

_pytest/runner.py

@@ -86,7 +86,17 @@ def pytest_runtest_setup(item):
     item.session._setupstate.prepare(item)
 
 def pytest_runtest_call(item):
+    try:
         item.runtest()
+    except Exception:
+        # Store trace info to allow postmortem debugging
+        type, value, tb = sys.exc_info()
+        tb = tb.tb_next  # Skip *this* frame
+        sys.last_type = type
+        sys.last_value = value
+        sys.last_traceback = tb
+        del tb  # Get rid of it in this namespace
+        raise
 
 def pytest_runtest_teardown(item, nextitem):
     item.session._setupstate.teardown_exact(item, nextitem)

doc/en/usage.txt

@@ -87,6 +87,17 @@ failure situation::
     py.test -x --pdb   # drop to PDB on first failure, then end test session
     py.test --pdb --maxfail=3  # drop to PDB for first three failures
 
+Note that on any failure the exception information is stored on 
+``sys.last_value``, ``sys.last_type`` and ``sys.last_traceback``. In
+interactive use, this allows one to drop into postmortem debugging with
+any debug tool. One can also manually access the exception information,
+for example::
+
+    >> import sys
+    >> sys.last_traceback.tb_lineno
+    42
+    >> sys.last_value
+    AssertionError('assert result == "ok"',)
 
 Setting a breakpoint / aka ``set_trace()``
 ----------------------------------------------------

testing/test_runner.py

@@ -525,3 +525,21 @@ def test_makereport_getsource(testdir):
     result = testdir.runpytest()
     assert 'INTERNALERROR' not in result.stdout.str()
     result.stdout.fnmatch_lines(['*else: assert False*'])
+
+
+def test_store_except_info_on_eror():
+    """ Test that upon test failure, the exception info is stored on
+    sys.last_traceback and friends.
+    """
+    # Simulate item that raises a specific exception
+    class ItemThatRaises:
+        def runtest(self):
+            raise IndexError('TEST')
+    try:
+        runner.pytest_runtest_call(ItemThatRaises())
+    except IndexError:
+        pass
+    # Check that exception info is stored on sys
+    assert sys.last_type is IndexError
+    assert sys.last_value.args[0] == 'TEST'
+    assert sys.last_traceback