Better exception messages for unittest assert methods.
- unittest.assertNotEqual() now uses the inequality operator (!=) instead
of the equality operator.
- Default assertTrue and assertFalse messages are now useful.
- TestCase has a longMessage attribute. This defaults to False, but if set to True
useful error messages are shown in addition to explicit messages passed to assert methods.
Issue #5663
diff --git a/Lib/unittest.py b/Lib/unittest.py
index c355f8f..b6b96b3 100644
--- a/Lib/unittest.py
+++ b/Lib/unittest.py
@@ -275,7 +275,7 @@
raise self.failureException(
"{0} not raised".format(exc_name))
if not issubclass(exc_type, self.expected):
- # let unexpexted exceptions pass through
+ # let unexpected exceptions pass through
return False
if self.expected_regex is None:
return True
@@ -318,6 +318,13 @@
failureException = AssertionError
+ # This attribute determines whether long messages (including repr of
+ # objects used in assert methods) will be printed on failure in *addition*
+ # to any explicit message passed.
+
+ longMessage = False
+
+
def __init__(self, methodName='runTest'):
"""Create an instance of the class that will use the named test
method when executed. Raises a ValueError if the instance does
@@ -471,13 +478,32 @@
def assertFalse(self, expr, msg=None):
"Fail the test if the expression is true."
if expr:
+ msg = self._formatMessage(msg, "%r is not False" % expr)
raise self.failureException(msg)
def assertTrue(self, expr, msg=None):
"""Fail the test unless the expression is true."""
if not expr:
+ msg = self._formatMessage(msg, "%r is not True" % expr)
raise self.failureException(msg)
+ def _formatMessage(self, msg, standardMsg):
+ """Honour the longMessage attribute when generating failure messages.
+ If longMessage is False this means:
+ * Use only an explicit message if it is provided
+ * Otherwise use the standard message for the assert
+
+ If longMessage is True:
+ * Use the standard message
+ * If an explicit message is provided, plus ' : ' and the explicit message
+ """
+ if not self.longMessage:
+ return msg or standardMsg
+ if msg is None:
+ return standardMsg
+ return standardMsg + ' : ' + msg
+
+
def assertRaises(self, excClass, callableObj=None, *args, **kwargs):
"""Fail unless an exception of class excClass is thrown
by callableObj when invoked with arguments args and keyword
@@ -523,7 +549,9 @@
def _baseAssertEqual(self, first, second, msg=None):
"""The default assertEqual implementation, not type specific."""
if not first == second:
- raise self.failureException(msg or '%r != %r' % (first, second))
+ standardMsg = '%r != %r' % (first, second)
+ msg = self._formatMessage(msg, standardMsg)
+ raise self.failureException(msg)
def assertEqual(self, first, second, msg=None):
"""Fail if the two objects are unequal as determined by the '=='
@@ -536,8 +564,9 @@
"""Fail if the two objects are equal as determined by the '=='
operator.
"""
- if first == second:
- raise self.failureException(msg or '%r == %r' % (first, second))
+ if not first != second:
+ msg = self._formatMessage(msg, '%r == %r' % (first, second))
+ raise self.failureException(msg)
def assertAlmostEqual(self, first, second, places=7, msg=None):
"""Fail if the two objects are unequal as determined by their
@@ -548,8 +577,9 @@
as significant digits (measured from the most signficant digit).
"""
if round(abs(second-first), places) != 0:
- raise self.failureException(
- msg or '%r != %r within %r places' % (first, second, places))
+ standardMsg = '%r != %r within %r places' % (first, second, places)
+ msg = self._formatMessage(msg, standardMsg)
+ raise self.failureException(msg)
def assertNotAlmostEqual(self, first, second, places=7, msg=None):
"""Fail if the two objects are equal as determined by their
@@ -560,8 +590,9 @@
as significant digits (measured from the most signficant digit).
"""
if round(abs(second-first), places) == 0:
- raise self.failureException(
- msg or '%r == %r within %r places' % (first, second, places))
+ standardMsg = '%r == %r within %r places' % (first, second, places)
+ msg = self._formatMessage(msg, standardMsg)
+ raise self.failureException(msg)
# Synonyms for assertion methods
@@ -680,10 +711,10 @@
except (TypeError, IndexError, NotImplementedError):
differing += ('Unable to index element %d '
'of second %s\n' % (len1, seq_type_name))
- if not msg:
- msg = '\n'.join(difflib.ndiff(pprint.pformat(seq1).splitlines(),
- pprint.pformat(seq2).splitlines()))
- self.fail(differing + msg)
+ standardMsg = differing + '\n'.join(difflib.ndiff(pprint.pformat(seq1).splitlines(),
+ pprint.pformat(seq2).splitlines()))
+ msg = self._formatMessage(msg, standardMsg)
+ self.fail(msg)
def assertListEqual(self, list1, list2, msg=None):
"""A list-specific equality assertion.
@@ -739,9 +770,6 @@
if not (difference1 or difference2):
return
- if msg is not None:
- self.fail(msg)
-
lines = []
if difference1:
lines.append('Items in the first set but not the second:')
@@ -751,28 +779,31 @@
lines.append('Items in the second set but not the first:')
for item in difference2:
lines.append(repr(item))
- self.fail('\n'.join(lines))
- def assertIn(self, a, b, msg=None):
- """Just like self.assert_(a in b), but with a nicer default message."""
- if msg is None:
- msg = '"%s" not found in "%s"' % (a, b)
- self.assert_(a in b, msg)
+ standardMsg = '\n'.join(lines)
+ self.fail(self._formatMessage(msg, standardMsg))
- def assertNotIn(self, a, b, msg=None):
- """Just like self.assert_(a not in b), but with a nicer default message."""
- if msg is None:
- msg = '"%s" unexpectedly found in "%s"' % (a, b)
- self.assert_(a not in b, msg)
+ def assertIn(self, member, container, msg=None):
+ """Just like self.assertTrue(a in b), but with a nicer default message."""
+ if member not in container:
+ standardMsg = '%r not found in %r' % (member, container)
+ self.fail(self._formatMessage(msg, standardMsg))
+
+ def assertNotIn(self, member, container, msg=None):
+ """Just like self.assertTrue(a not in b), but with a nicer default message."""
+ if member in container:
+ standardMsg = '%r unexpectedly found in %r' % (member, container)
+ self.fail(self._formatMessage(msg, standardMsg))
def assertDictEqual(self, d1, d2, msg=None):
self.assert_(isinstance(d1, dict), 'First argument is not a dictionary')
self.assert_(isinstance(d2, dict), 'Second argument is not a dictionary')
if d1 != d2:
- self.fail(msg or ('\n' + '\n'.join(difflib.ndiff(
- pprint.pformat(d1).splitlines(),
- pprint.pformat(d2).splitlines()))))
+ standardMsg = ('\n' + '\n'.join(difflib.ndiff(
+ pprint.pformat(d1).splitlines(),
+ pprint.pformat(d2).splitlines())))
+ self.fail(self._formatMessage(msg, standardMsg))
def assertDictContainsSubset(self, expected, actual, msg=None):
"""Checks whether actual is a superset of expected."""
@@ -782,23 +813,20 @@
if key not in actual:
missing.append(key)
elif value != actual[key]:
- mismatched.append('%s, expected: %s, actual: %s' % (key, value,
- actual[key]))
+ mismatched.append('%s, expected: %s, actual: %s' % (key, value, actual[key]))
if not (missing or mismatched):
return
- missing_msg = mismatched_msg = ''
+ standardMsg = ''
if missing:
- missing_msg = 'Missing: %s' % ','.join(missing)
+ standardMsg = 'Missing: %r' % ','.join(missing)
if mismatched:
- mismatched_msg = 'Mismatched values: %s' % ','.join(mismatched)
+ if standardMsg:
+ standardMsg += '; '
+ standardMsg += 'Mismatched values: %s' % ','.join(mismatched)
- if msg:
- msg = '%s: %s; %s' % (msg, missing_msg, mismatched_msg)
- else:
- msg = '%s; %s' % (missing_msg, mismatched_msg)
- self.fail(msg)
+ self.fail(self._formatMessage(msg, standardMsg))
def assertSameElements(self, expected_seq, actual_seq, msg=None):
"""An unordered sequence specific comparison.
@@ -823,57 +851,59 @@
missing, unexpected = _SortedListDifference(expected, actual)
errors = []
if missing:
- errors.append('Expected, but missing:\n %r\n' % missing)
+ errors.append('Expected, but missing:\n %r' % missing)
if unexpected:
- errors.append('Unexpected, but present:\n %r\n' % unexpected)
+ errors.append('Unexpected, but present:\n %r' % unexpected)
if errors:
- self.fail(msg or ''.join(errors))
+ standardMsg = '\n'.join(errors)
+ self.fail(self._formatMessage(msg, standardMsg))
def assertMultiLineEqual(self, first, second, msg=None):
"""Assert that two multi-line strings are equal."""
- self.assert_(isinstance(first, types.StringTypes), (
+ self.assert_(isinstance(first, basestring), (
'First argument is not a string'))
- self.assert_(isinstance(second, types.StringTypes), (
+ self.assert_(isinstance(second, basestring), (
'Second argument is not a string'))
if first != second:
- raise self.failureException(
- msg or '\n' + ''.join(difflib.ndiff(first.splitlines(True),
- second.splitlines(True))))
+ standardMsg = '\n' + ''.join(difflib.ndiff(first.splitlines(True), second.splitlines(True)))
+ self.fail(self._formatMessage(msg, standardMsg))
def assertLess(self, a, b, msg=None):
- """Just like self.assert_(a < b), but with a nicer default message."""
- if msg is None:
- msg = '"%r" unexpectedly not less than "%r"' % (a, b)
- self.assert_(a < b, msg)
+ """Just like self.assertTrue(a < b), but with a nicer default message."""
+ if not a < b:
+ standardMsg = '%r not less than %r' % (a, b)
+ self.fail(self._formatMessage(msg, standardMsg))
def assertLessEqual(self, a, b, msg=None):
- """Just like self.assert_(a <= b), but with a nicer default message."""
- if msg is None:
- msg = '"%r" unexpectedly not less than or equal to "%r"' % (a, b)
- self.assert_(a <= b, msg)
+ """Just like self.assertTrue(a <= b), but with a nicer default message."""
+ if not a <= b:
+ standardMsg = '%r not less than or equal to %r' % (a, b)
+ self.fail(self._formatMessage(msg, standardMsg))
def assertGreater(self, a, b, msg=None):
- """Just like self.assert_(a > b), but with a nicer default message."""
- if msg is None:
- msg = '"%r" unexpectedly not greater than "%r"' % (a, b)
- self.assert_(a > b, msg)
+ """Just like self.assertTrue(a > b), but with a nicer default message."""
+ if not a > b:
+ standardMsg = '%r not greater than %r' % (a, b)
+ self.fail(self._formatMessage(msg, standardMsg))
def assertGreaterEqual(self, a, b, msg=None):
- """Just like self.assert_(a >= b), but with a nicer default message."""
- if msg is None:
- msg = '"%r" unexpectedly not greater than or equal to "%r"' % (a, b)
- self.assert_(a >= b, msg)
+ """Just like self.assertTrue(a >= b), but with a nicer default message."""
+ if not a >= b:
+ standardMsg = '%r not greater than or equal to %r' % (a, b)
+ self.fail(self._formatMessage(msg, standardMsg))
def assertIsNone(self, obj, msg=None):
- """Same as self.assert_(obj is None), with a nicer default message."""
- if msg is None:
- msg = '"%s" unexpectedly not None' % obj
- self.assert_(obj is None, msg)
+ """Same as self.assertTrue(obj is None), with a nicer default message."""
+ if obj is not None:
+ standardMsg = '%r is not None' % obj
+ self.fail(self._formatMessage(msg, standardMsg))
- def assertIsNotNone(self, obj, msg='unexpectedly None'):
+ def assertIsNotNone(self, obj, msg=None):
"""Included for symmetry with assertIsNone."""
- self.assert_(obj is not None, msg)
+ if obj is None:
+ standardMsg = 'unexpectedly None'
+ self.fail(self._formatMessage(msg, standardMsg))
def assertRaisesRegexp(self, expected_exception, expected_regexp,
callable_obj=None, *args, **kwargs):