Merge pull request #1746 from pytest-dev/conftest-exception-printing

Conftest exception printing

Author: nicoddemus

AUTHORS

@@ -61,6 +61,7 @@ Jaap Broekhuizen
 Jan Balster
 Janne Vanhala
 Jason R. Coombs
+Javier Domingo Cansino
 John Towler
 Joshua Bronson
 Jurko Gospodnetić

CHANGELOG.rst

@@ -60,8 +60,6 @@ time or change existing behaviors in order to make them less surprising/more use
 
 *
 
-*
-
 **New Features**
 
 * Support nose-style ``__test__`` attribute on methods of classes,
@@ -251,6 +249,10 @@ time or change existing behaviors in order to make them less surprising/more use
   Thanks `@Vogtinator`_ for reporting and `@RedBeardCode`_ and
   `@tomviner`_ for the PR.
 
+* ``ConftestImportFailure`` now shows the traceback making it easier to
+  identify bugs in ``conftest.py`` files (`#1516`_). Thanks `@txomon`_ for
+  the PR.
+
 *
 
 *
@@ -281,6 +283,7 @@ time or change existing behaviors in order to make them less surprising/more use
 .. _#1479: https://github.com/pytest-dev/pytest/issues/1479
 .. _#1502: https://github.com/pytest-dev/pytest/pull/1502
 .. _#1503: https://github.com/pytest-dev/pytest/issues/1503
+.. _#1516: https://github.com/pytest-dev/pytest/pull/1516
 .. _#1519: https://github.com/pytest-dev/pytest/pull/1519
 .. _#1520: https://github.com/pytest-dev/pytest/pull/1520
 .. _#1526: https://github.com/pytest-dev/pytest/pull/1526
@@ -333,6 +336,7 @@ time or change existing behaviors in order to make them less surprising/more use
 .. _@sober7: https://github.com/sober7
 .. _@tareqalayan: https://github.com/tareqalayan
 .. _@taschini: https://github.com/taschini
+.. _@txomon: https://github.com/txomon
 
 2.9.2
 =====

_pytest/config.py

@@ -27,6 +27,12 @@ def __init__(self, path, excinfo):
         self.path = path
         self.excinfo = excinfo
 
+    def __str__(self):
+        etype, evalue, etb = self.excinfo
+        formatted = traceback.format_tb(etb)
+        # The level of the tracebacks we want to print is hand crafted :(
+        return repr(evalue) + '\n' + ''.join(formatted[2:])
+
 
 def main(args=None, plugins=None):
     """ return exit code, after performing an in-process test run.

testing/test_conftest.py

@@ -408,3 +408,16 @@ def test_some():
     """)
     res = testdir.runpytest()
     assert res.ret == 0
+
+
+def test_conftest_exception_handling(testdir):
+    testdir.makeconftest('''
+        raise ValueError()
+    ''')
+    testdir.makepyfile("""
+        def test_some():
+            pass
+    """)
+    res = testdir.runpytest()
+    assert res.ret == 4
+    assert 'raise ValueError()' in [line.strip() for line in res.errlines]