pytest-dev · nicoddemus · May 3, 2018 · May 1, 2018 · May 1, 2018 · nicoddemus
diff --git a/_pytest/debugging.py b/_pytest/debugging.py
@@ -16,7 +16,7 @@ def pytest_addoption(parser):
     group = parser.getgroup("general")
     group._addoption(
         '--pdb', dest="usepdb", action="store_true",
-        help="start the interactive Python debugger on errors.")
+        help="start the interactive Python debugger on errors or KeyboardInterrupt.")
     group._addoption(
         '--pdbcls', dest="usepdb_cls", metavar="modulename:classname",
         help="start a custom interactive Python debugger on errors. "

diff --git a/_pytest/runner.py b/_pytest/runner.py
@@ -176,24 +176,28 @@ def check_interactive_exception(call, report):
 def call_runtest_hook(item, when, **kwds):
     hookname = "pytest_runtest_" + when
     ihook = getattr(item.ihook, hookname)
-    return CallInfo(lambda: ihook(item=item, **kwds), when=when)
+    return CallInfo(lambda: ihook(item=item, **kwds), when=when,
+                    treat_keyboard_interrupt_as_exception=item.config.getvalue("usepdb"))
 
 
 class CallInfo(object):
     """ Result/Exception info a function invocation. """
     #: None or ExceptionInfo object.
     excinfo = None
 
-    def __init__(self, func, when):
+    def __init__(self, func, when, treat_keyboard_interrupt_as_exception=False):
         #: context of invocation: one of "setup", "call",
         #: "teardown", "memocollect"
         self.when = when
         self.start = time()
         try:
             self.result = func()
         except KeyboardInterrupt:
-            self.stop = time()
-            raise
+            if treat_keyboard_interrupt_as_exception:
+                self.excinfo = ExceptionInfo()
+            else:
+                self.stop = time()
+                raise
         except:  # noqa
             self.excinfo = ExceptionInfo()
         self.stop = time()

diff --git a/changelog/3299.feature.rst b/changelog/3299.feature.rst
@@ -0,0 +1,2 @@
+The ``--pdb`` option now causes KeyboardInterrupt to enter the debugger, instead of stopping the test session.
+On python 2.7, hitting CTRL+C again exits the debugger. On python 3.2 and higher, use CTRL+D.
diff --git a/doc/en/usage.rst b/doc/en/usage.rst
@@ -152,9 +152,9 @@ allows one to drop into the PDB_ prompt via a command line option::
 
     pytest --pdb
 
-This will invoke the Python debugger on every failure.  Often you might
-only want to do this for the first failing test to understand a certain
-failure situation::
+This will invoke the Python debugger on every failure (or KeyboardInterrupt).
+Often you might only want to do this for the first failing test to understand
+a certain failure situation::
 
     pytest -x --pdb   # drop to PDB on first failure, then end test session
     pytest --pdb --maxfail=3  # drop to PDB for first three failures

diff --git a/testing/test_pdb.py b/testing/test_pdb.py
@@ -114,6 +114,14 @@ def test_func():
         assert rep.failed
         assert len(pdblist) == 0
 
+    def test_pdb_on_KeyboardInterrupt(self, testdir, pdblist):
+        rep = runpdb_and_get_report(testdir, """
+            def test_func():
+                raise KeyboardInterrupt
+        """)
+        assert rep.failed
+        assert len(pdblist) == 1
+
     def test_pdb_interaction(self, testdir):
         p1 = testdir.makepyfile("""
             def test_1():
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,2 @@
		The ``--pdb`` option now causes KeyboardInterrupt to enter the debugger, instead of stopping the test session.
Copy link Member nicoddemus May 1, 2018 • edited Loading Choose a reason for hiding this comment The reason will be displayed to describe this comment to others. Learn more. Just to make sure: hitting CTRL+C again after landing on the debugger causes the debugger to exit right? Copy link Contributor Author brianmaissy May 1, 2018 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others. Learn more. Yes. I'll try to add a test that verifies that. Should I mention it in the changelog or docs? Copy link Member nicoddemus May 1, 2018 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others. Learn more. I think just mentioning it in the changelog is sufficient, something like: ... instead of stopping the test session. Hitting CTRL+C again exits the debugger. Copy link Member nicoddemus May 1, 2018 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others. Learn more. I see the test failed... not sure if it is easy to fix it; if not I'm OK with dropping the test, I think it is enough to ensure that we enter pdb when we get a `KeyboardInterrupt`. Copy link Contributor Author brianmaissy May 1, 2018 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others. Learn more. I also expected the test to fail because of pexpect's `kill` method not being cross-platform or something like that, but actually the test failed because pdb indeed behaves differently in python 3.6, and the KeyboardInterrupt does not cause it to exit. Are we ok with that? Copy link Contributor Author brianmaissy May 1, 2018 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others. Learn more. looks like it was an intentional change: https://bugs.python.org/issue7245. Haha now I understand the discussion on the issue. Copy link Contributor Author brianmaissy May 1, 2018 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others. Learn more. The `nosigint` parameter to the Pdb constructor is supposed to disable that functionality, according to the docs (https://docs.python.org/3/library/pdb.html#pdb.Pdb). For some reason it doesn't seem to be working for me, but I can continue looking into it if we care about it. On the other hand, probably better to let the pdb act like it usually acts for each version of python. Copy link Member nicoddemus May 1, 2018 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others. Learn more. On the other hand, probably better to let the pdb act like it usually acts for each version of python. Definitely, I agree! Thanks for researching this. 👍
		On python 2.7, hitting CTRL+C again exits the debugger. On python 3.2 and higher, use CTRL+D.