[Python-checkins] cpython: #16522: Add FAIL_FAST flag to doctest.

Wed Nov 21 21:09:52 CET 2012

http://hg.python.org/cpython/rev/966432a0734c
changeset: 80552:966432a0734c
user: R David Murray <rdmurray at bitdance.com>
date: Wed Nov 21 15:09:21 2012 -0500
summary:
 #16522: Add FAIL_FAST flag to doctest.
Patch by me, most of the work (doc and tests) by Daniel Urban.
files:
 Doc/library/doctest.rst | 10 +++++
 Doc/whatsnew/3.4.rst | 6 ++-
 Lib/doctest.py | 8 ++++-
 Lib/test/test_doctest.py | 47 ++++++++++++++++++++++++++-
 Misc/NEWS | 2 +
 5 files changed, 69 insertions(+), 4 deletions(-)

diff --git a/Doc/library/doctest.rst b/Doc/library/doctest.rst
--- a/Doc/library/doctest.rst
+++ b/Doc/library/doctest.rst
@@ -633,6 +633,16 @@
 the output is suppressed.
 
 
+.. data:: FAIL_FAST
+
+ When specified, exit after the first failing example and don't attempt to run
+ the remaining examples. Thus, the number of failures reported will always be 1.
+ This flag may be useful during debugging, since examples after the first
+ failure won't even produce debugging output.
+
+ .. versionadded:: 3.4
+
+
 .. data:: REPORTING_FLAGS
 
 A bitmask or'ing together all the reporting flags above.
diff --git a/Doc/whatsnew/3.4.rst b/Doc/whatsnew/3.4.rst
--- a/Doc/whatsnew/3.4.rst
+++ b/Doc/whatsnew/3.4.rst
@@ -150,7 +150,11 @@
 Improved Modules
 ================
 
-* None yet.
+doctest
+-------
+
+Added ``FAIL_FAST`` flag to halt test running as soon as the first failure is
+detected. (Contributed by R. David Murray and Daniel Urban in :issue:`16522`.)
 
 
 Optimizations
diff --git a/Lib/doctest.py b/Lib/doctest.py
--- a/Lib/doctest.py
+++ b/Lib/doctest.py
@@ -62,6 +62,7 @@
 'REPORT_NDIFF',
 'REPORT_ONLY_FIRST_FAILURE',
 'REPORTING_FLAGS',
+ 'FAIL_FAST',
 # 1. Utility Functions
 # 2. Example & DocTest
 'Example',
@@ -150,11 +151,13 @@
 REPORT_CDIFF = register_optionflag('REPORT_CDIFF')
 REPORT_NDIFF = register_optionflag('REPORT_NDIFF')
 REPORT_ONLY_FIRST_FAILURE = register_optionflag('REPORT_ONLY_FIRST_FAILURE')
+FAIL_FAST = register_optionflag('FAIL_FAST')
 
 REPORTING_FLAGS = (REPORT_UDIFF |
 REPORT_CDIFF |
 REPORT_NDIFF |
- REPORT_ONLY_FIRST_FAILURE)
+ REPORT_ONLY_FIRST_FAILURE |
+ FAIL_FAST)
 
 # Special string markers for use in `want` strings:
 BLANKLINE_MARKER = '<BLANKLINE>'
@@ -1342,6 +1345,9 @@
 else:
 assert False, ("unknown outcome", outcome)
 
+ if failures and self.optionflags & FAIL_FAST:
+ break
+
 # Restore the option flags (in case they were modified)
 self.optionflags = original_optionflags
 
diff --git a/Lib/test/test_doctest.py b/Lib/test/test_doctest.py
--- a/Lib/test/test_doctest.py
+++ b/Lib/test/test_doctest.py
@@ -1409,8 +1409,40 @@
 2
 TestResults(failed=3, attempted=5)
 
-For the purposes of REPORT_ONLY_FIRST_FAILURE, unexpected exceptions
-count as failures:
+The FAIL_FAST flag causes the runner to exit after the first failing example,
+so subsequent examples are not even attempted:
+
+ >>> flags = doctest.FAIL_FAST
+ >>> doctest.DocTestRunner(verbose=False, optionflags=flags).run(test)
+ ... # doctest: +ELLIPSIS
+ **********************************************************************
+ File ..., line 5, in f
+ Failed example:
+ print(2) # first failure
+ Expected:
+ 200
+ Got:
+ 2
+ TestResults(failed=1, attempted=2)
+
+Specifying both FAIL_FAST and REPORT_ONLY_FIRST_FAILURE is equivalent to
+FAIL_FAST only:
+
+ >>> flags = doctest.FAIL_FAST | doctest.REPORT_ONLY_FIRST_FAILURE
+ >>> doctest.DocTestRunner(verbose=False, optionflags=flags).run(test)
+ ... # doctest: +ELLIPSIS
+ **********************************************************************
+ File ..., line 5, in f
+ Failed example:
+ print(2) # first failure
+ Expected:
+ 200
+ Got:
+ 2
+ TestResults(failed=1, attempted=2)
+
+For the purposes of both REPORT_ONLY_FIRST_FAILURE and FAIL_FAST, unexpected
+exceptions count as failures:
 
 >>> def f(x):
 ... r'''
@@ -1437,6 +1469,17 @@
 ...
 ValueError: 2
 TestResults(failed=3, attempted=5)
+ >>> flags = doctest.FAIL_FAST
+ >>> doctest.DocTestRunner(verbose=False, optionflags=flags).run(test)
+ ... # doctest: +ELLIPSIS
+ **********************************************************************
+ File ..., line 5, in f
+ Failed example:
+ raise ValueError(2) # first failure
+ Exception raised:
+ ...
+ ValueError: 2
+ TestResults(failed=1, attempted=2)
 
 New option flags can also be registered, via register_optionflag(). Here
 we reach into doctest's internals a bit.
diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -138,6 +138,8 @@
 Library
 -------
 
+- Issue #16522: added FAIL_FAST flag to doctest.
+
 - Issue #15627: Add the importlib.abc.SourceLoader.compile_source() method.
 
 - Issue #16408: Fix file descriptors not being closed in error conditions
-- 
Repository URL: http://hg.python.org/cpython
