The unittest.TestCase.assertEqual() now displays the differences in lists,

tuples, dicts and sets on failure.

Many new handy type and comparison specific assert* methods have been added
that fail with error messages actually useful for debugging.  Contributed in
by Google and completed with help from mfoord and GvR at PyCon 2009 sprints.

Discussion lives in http://bugs.python.org/issue2578.

1 files changed, 417 insertions, 47 deletions

diff --git a/Lib/test/test_unittest.py b/Lib/test/test_unittest.py
index b0b86be864..85ebf46e74 100644
--- a/Lib/test/test_unittest.py
+++ b/Lib/test/test_unittest.py
@@ -6,6 +6,7 @@ Still need testing:
     TestCase.{assert,fail}* methods (some are tested implicitly)
 """
 
+import re
 from test import test_support
 import unittest
 from unittest import TestCase
@@ -70,21 +71,20 @@ class TestHashing(object):
     def test_hash(self):
         for obj_1, obj_2 in self.eq_pairs:
             try:
-                assert hash(obj_1) == hash(obj_2)
+                if not hash(obj_1) == hash(obj_2):
+                    self.fail("%r and %r do not hash equal" % (obj_1, obj_2))
             except KeyboardInterrupt:
                 raise
-            except AssertionError:
-                self.fail("%s and %s do not hash equal" % (obj_1, obj_2))
             except Exception, e:
-                self.fail("Problem hashing %s and %s: %s" % (obj_1, obj_2, e))
+                self.fail("Problem hashing %r and %r: %s" % (obj_1, obj_2, e))
 
         for obj_1, obj_2 in self.ne_pairs:
             try:
-                assert hash(obj_1) != hash(obj_2)
+                if hash(obj_1) == hash(obj_2):
+                    self.fail("%s and %s hash equal, but shouldn't" %
+                              (obj_1, obj_2))
             except KeyboardInterrupt:
                 raise
-            except AssertionError:
-                self.fail("%s and %s hash equal, but shouldn't" % (obj_1, obj_2))
             except Exception, e:
                 self.fail("Problem hashing %s and %s: %s" % (obj_1, obj_2, e))
 
@@ -2237,39 +2237,6 @@ class Test_TestCase(TestCase, TestEquality, TestHashing):
 
         self.failUnless(isinstance(Foo().id(), basestring))
 
-    # "Returns a one-line description of the test, or None if no description
-    # has been provided. The default implementation of this method returns
-    # the first line of the test method's docstring, if available, or None."
-    def test_shortDescription__no_docstring(self):
-        class Foo(unittest.TestCase):
-            def runTest(self):
-                pass
-
-        self.assertEqual(Foo().shortDescription(), None)
-
-    # "Returns a one-line description of the test, or None if no description
-    # has been provided. The default implementation of this method returns
-    # the first line of the test method's docstring, if available, or None."
-    def test_shortDescription__singleline_docstring(self):
-        class Foo(unittest.TestCase):
-            def runTest(self):
-                "this tests foo"
-                pass
-
-        self.assertEqual(Foo().shortDescription(), "this tests foo")
-
-    # "Returns a one-line description of the test, or None if no description
-    # has been provided. The default implementation of this method returns
-    # the first line of the test method's docstring, if available, or None."
-    def test_shortDescription__multiline_docstring(self):
-        class Foo(unittest.TestCase):
-            def runTest(self):
-                """this tests foo
-                blah, bar and baz are also tested"""
-                pass
-
-        self.assertEqual(Foo().shortDescription(), "this tests foo")
-
     # "If result is omitted or None, a temporary result object is created
     # and used, but is not made available to the caller"
     def test_run__uses_defaultTestResult(self):
@@ -2288,6 +2255,409 @@ class Test_TestCase(TestCase, TestEquality, TestHashing):
         expected = ['startTest', 'test', 'addSuccess', 'stopTest']
         self.assertEqual(events, expected)
 
+    def testShortDescriptionWithoutDocstring(self):
+        self.assertEqual(
+                self.shortDescription(),
+                'testShortDescriptionWithoutDocstring (' + __name__ +
+                '.Test_TestCase)')
+
+    def testShortDescriptionWithOneLineDocstring(self):
+        """Tests shortDescription() for a method with a docstring."""
+        self.assertEqual(
+                self.shortDescription(),
+                ('testShortDescriptionWithOneLineDocstring '
+                 '(' + __name__ + '.Test_TestCase)\n'
+                 'Tests shortDescription() for a method with a docstring.'))
+
+    def testShortDescriptionWithMultiLineDocstring(self):
+        """Tests shortDescription() for a method with a longer docstring.
+
+        This method ensures that only the first line of a docstring is
+        returned used in the short description, no matter how long the
+        whole thing is.
+        """
+        self.assertEqual(
+                self.shortDescription(),
+                ('testShortDescriptionWithMultiLineDocstring '
+                 '(' + __name__ + '.Test_TestCase)\n'
+                 'Tests shortDescription() for a method with a longer '
+                 'docstring.'))
+
+
+    def testAddTypeEqualityFunc(self):
+        class SadSnake(object):
+            """Dummy class for test_addTypeEqualityFunc."""
+        s1, s2 = SadSnake(), SadSnake()
+        self.assertFalse(s1 == s2)
+        def AllSnakesCreatedEqual(a, b, msg=None):
+            return type(a) == type(b) == SadSnake
+        self.addTypeEqualityFunc(SadSnake, AllSnakesCreatedEqual)
+        self.assertEqual(s1, s2)
+        # No this doesn't clean up and remove the SadSnake equality func
+        # from this TestCase instance but since its a local nothing else
+        # will ever notice that.
+
+    def testAssertIn(self):
+        animals = {'monkey': 'banana', 'cow': 'grass', 'seal': 'fish'}
+
+        self.assertIn('a', 'abc')
+        self.assertIn(2, [1, 2, 3])
+        self.assertIn('monkey', animals)
+
+        self.assertNotIn('d', 'abc')
+        self.assertNotIn(0, [1, 2, 3])
+        self.assertNotIn('otter', animals)
+
+        self.assertRaises(self.failureException, self.assertIn, 'x', 'abc')
+        self.assertRaises(self.failureException, self.assertIn, 4, [1, 2, 3])
+        self.assertRaises(self.failureException, self.assertIn, 'elephant',
+                          animals)
+
+        self.assertRaises(self.failureException, self.assertNotIn, 'c', 'abc')
+        self.assertRaises(self.failureException, self.assertNotIn, 1, [1, 2, 3])
+        self.assertRaises(self.failureException, self.assertNotIn, 'cow',
+                          animals)
+
+    def testAssertDictContainsSubset(self):
+        self.assertDictContainsSubset({}, {})
+        self.assertDictContainsSubset({}, {'a': 1})
+        self.assertDictContainsSubset({'a': 1}, {'a': 1})
+        self.assertDictContainsSubset({'a': 1}, {'a': 1, 'b': 2})
+        self.assertDictContainsSubset({'a': 1, 'b': 2}, {'a': 1, 'b': 2})
+
+        self.assertRaises(unittest.TestCase.failureException,
+                          self.assertDictContainsSubset, {'a': 2}, {'a': 1},
+                          '.*Mismatched values:.*')
+
+        self.assertRaises(unittest.TestCase.failureException,
+                          self.assertDictContainsSubset, {'c': 1}, {'a': 1},
+                          '.*Missing:.*')
+
+        self.assertRaises(unittest.TestCase.failureException,
+                          self.assertDictContainsSubset, {'a': 1, 'c': 1},
+                          {'a': 1}, '.*Missing:.*')
+
+        self.assertRaises(unittest.TestCase.failureException,
+                          self.assertDictContainsSubset, {'a': 1, 'c': 1},
+                          {'a': 1}, '.*Missing:.*Mismatched values:.*')
+
+    def testAssertEqual(self):
+        equal_pairs = [
+                ((), ()),
+                ({}, {}),
+                ([], []),
+                (set(), set()),
+                (frozenset(), frozenset())]
+        for a, b in equal_pairs:
+            # This mess of try excepts is to test the assertEqual behavior
+            # itself.
+            try:
+                self.assertEqual(a, b)
+            except self.failureException:
+                self.fail('assertEqual(%r, %r) failed' % (a, b))
+            try:
+                self.assertEqual(a, b, msg='foo')
+            except self.failureException:
+                self.fail('assertEqual(%r, %r) with msg= failed' % (a, b))
+            try:
+                self.assertEqual(a, b, 'foo')
+            except self.failureException:
+                self.fail('assertEqual(%r, %r) with third parameter failed' %
+                          (a, b))
+
+        unequal_pairs = [
+               ((), []),
+               ({}, set()),
+               (set([4,1]), frozenset([4,2])),
+               (frozenset([4,5]), set([2,3])),
+               (set([3,4]), set([5,4]))]
+        for a, b in unequal_pairs:
+            self.assertRaises(self.failureException, self.assertEqual, a, b)
+            self.assertRaises(self.failureException, self.assertEqual, a, b,
+                              'foo')
+            self.assertRaises(self.failureException, self.assertEqual, a, b,
+                              msg='foo')
+
+    def testEquality(self):
+        self.assertListEqual([], [])
+        self.assertTupleEqual((), ())
+        self.assertSequenceEqual([], ())
+
+        a = [0, 'a', []]
+        b = []
+        self.assertRaises(unittest.TestCase.failureException,
+                          self.assertListEqual, a, b)
+        self.assertRaises(unittest.TestCase.failureException,
+                          self.assertListEqual, tuple(a), tuple(b))
+        self.assertRaises(unittest.TestCase.failureException,
+                          self.assertSequenceEqual, a, tuple(b))
+
+        b.extend(a)
+        self.assertListEqual(a, b)
+        self.assertTupleEqual(tuple(a), tuple(b))
+        self.assertSequenceEqual(a, tuple(b))
+        self.assertSequenceEqual(tuple(a), b)
+
+        self.assertRaises(self.failureException, self.assertListEqual,
+                          a, tuple(b))
+        self.assertRaises(self.failureException, self.assertTupleEqual,
+                          tuple(a), b)
+        self.assertRaises(self.failureException, self.assertListEqual, None, b)
+        self.assertRaises(self.failureException, self.assertTupleEqual, None,
+                          tuple(b))
+        self.assertRaises(self.failureException, self.assertSequenceEqual,
+                          None, tuple(b))
+        self.assertRaises(self.failureException, self.assertListEqual, 1, 1)
+        self.assertRaises(self.failureException, self.assertTupleEqual, 1, 1)
+        self.assertRaises(self.failureException, self.assertSequenceEqual,
+                          1, 1)
+
+        self.assertDictEqual({}, {})
+
+        c = { 'x': 1 }
+        d = {}
+        self.assertRaises(unittest.TestCase.failureException,
+                          self.assertDictEqual, c, d)
+
+        d.update(c)
+        self.assertDictEqual(c, d)
+
+        d['x'] = 0
+        self.assertRaises(unittest.TestCase.failureException,
+                          self.assertDictEqual, c, d, 'These are unequal')
+
+        self.assertRaises(self.failureException, self.assertDictEqual, None, d)
+        self.assertRaises(self.failureException, self.assertDictEqual, [], d)
+        self.assertRaises(self.failureException, self.assertDictEqual, 1, 1)
+
+        self.assertSameElements([1, 2, 3], [3, 2, 1])
+        self.assertSameElements([1, 2] + [3] * 100, [1] * 100 + [2, 3])
+        self.assertSameElements(['foo', 'bar', 'baz'], ['bar', 'baz', 'foo'])
+        self.assertRaises(self.failureException, self.assertSameElements,
+                          [10], [10, 11])
+        self.assertRaises(self.failureException, self.assertSameElements,
+                          [10, 11], [10])
+
+        # Test that sequences of unhashable objects can be tested for sameness:
+        self.assertSameElements([[1, 2], [3, 4]], [[3, 4], [1, 2]])
+        self.assertSameElements([{'a': 1}, {'b': 2}], [{'b': 2}, {'a': 1}])
+        self.assertRaises(self.failureException, self.assertSameElements,
+                          [[1]], [[2]])
+
+    def testAssertSetEqual(self):
+        set1 = set()
+        set2 = set()
+        self.assertSetEqual(set1, set2)
+
+        self.assertRaises(self.failureException, self.assertSetEqual, None, set2)
+        self.assertRaises(self.failureException, self.assertSetEqual, [], set2)
+        self.assertRaises(self.failureException, self.assertSetEqual, set1, None)
+        self.assertRaises(self.failureException, self.assertSetEqual, set1, [])
+
+        set1 = set(['a'])
+        set2 = set()
+        self.assertRaises(self.failureException, self.assertSetEqual, set1, set2)
+
+        set1 = set(['a'])
+        set2 = set(['a'])
+        self.assertSetEqual(set1, set2)
+
+        set1 = set(['a'])
+        set2 = set(['a', 'b'])
+        self.assertRaises(self.failureException, self.assertSetEqual, set1, set2)
+
+        set1 = set(['a'])
+        set2 = frozenset(['a', 'b'])
+        self.assertRaises(self.failureException, self.assertSetEqual, set1, set2)
+
+        set1 = set(['a', 'b'])
+        set2 = frozenset(['a', 'b'])
+        self.assertSetEqual(set1, set2)
+
+        set1 = set()
+        set2 = "foo"
+        self.assertRaises(self.failureException, self.assertSetEqual, set1, set2)
+        self.assertRaises(self.failureException, self.assertSetEqual, set2, set1)
+
+        # make sure any string formatting is tuple-safe
+        set1 = set([(0, 1), (2, 3)])
+        set2 = set([(4, 5)])
+        self.assertRaises(self.failureException, self.assertSetEqual, set1, set2)
+
+    def testInequality(self):
+        # Try ints
+        self.assertGreater(2, 1)
+        self.assertGreaterEqual(2, 1)
+        self.assertGreaterEqual(1, 1)
+        self.assertLess(1, 2)
+        self.assertLessEqual(1, 2)
+        self.assertLessEqual(1, 1)
+        self.assertRaises(self.failureException, self.assertGreater, 1, 2)
+        self.assertRaises(self.failureException, self.assertGreater, 1, 1)
+        self.assertRaises(self.failureException, self.assertGreaterEqual, 1, 2)
+        self.assertRaises(self.failureException, self.assertLess, 2, 1)
+        self.assertRaises(self.failureException, self.assertLess, 1, 1)
+        self.assertRaises(self.failureException, self.assertLessEqual, 2, 1)
+
+        # Try Floats
+        self.assertGreater(1.1, 1.0)
+        self.assertGreaterEqual(1.1, 1.0)
+        self.assertGreaterEqual(1.0, 1.0)
+        self.assertLess(1.0, 1.1)
+        self.assertLessEqual(1.0, 1.1)
+        self.assertLessEqual(1.0, 1.0)
+        self.assertRaises(self.failureException, self.assertGreater, 1.0, 1.1)
+        self.assertRaises(self.failureException, self.assertGreater, 1.0, 1.0)
+        self.assertRaises(self.failureException, self.assertGreaterEqual, 1.0, 1.1)
+        self.assertRaises(self.failureException, self.assertLess, 1.1, 1.0)
+        self.assertRaises(self.failureException, self.assertLess, 1.0, 1.0)
+        self.assertRaises(self.failureException, self.assertLessEqual, 1.1, 1.0)
+
+        # Try Strings
+        self.assertGreater('bug', 'ant')
+        self.assertGreaterEqual('bug', 'ant')
+        self.assertGreaterEqual('ant', 'ant')
+        self.assertLess('ant', 'bug')
+        self.assertLessEqual('ant', 'bug')
+        self.assertLessEqual('ant', 'ant')
+        self.assertRaises(self.failureException, self.assertGreater, 'ant', 'bug')
+        self.assertRaises(self.failureException, self.assertGreater, 'ant', 'ant')
+        self.assertRaises(self.failureException, self.assertGreaterEqual, 'ant', 'bug')
+        self.assertRaises(self.failureException, self.assertLess, 'bug', 'ant')
+        self.assertRaises(self.failureException, self.assertLess, 'ant', 'ant')
+        self.assertRaises(self.failureException, self.assertLessEqual, 'bug', 'ant')
+
+        # Try Unicode
+        self.assertGreater(u'bug', u'ant')
+        self.assertGreaterEqual(u'bug', u'ant')
+        self.assertGreaterEqual(u'ant', u'ant')
+        self.assertLess(u'ant', u'bug')
+        self.assertLessEqual(u'ant', u'bug')
+        self.assertLessEqual(u'ant', u'ant')
+        self.assertRaises(self.failureException, self.assertGreater, u'ant', u'bug')
+        self.assertRaises(self.failureException, self.assertGreater, u'ant', u'ant')
+        self.assertRaises(self.failureException, self.assertGreaterEqual, u'ant',
+                          u'bug')
+        self.assertRaises(self.failureException, self.assertLess, u'bug', u'ant')
+        self.assertRaises(self.failureException, self.assertLess, u'ant', u'ant')
+        self.assertRaises(self.failureException, self.assertLessEqual, u'bug', u'ant')
+
+        # Try Mixed String/Unicode
+        self.assertGreater('bug', u'ant')
+        self.assertGreater(u'bug', 'ant')
+        self.assertGreaterEqual('bug', u'ant')
+        self.assertGreaterEqual(u'bug', 'ant')
+        self.assertGreaterEqual('ant', u'ant')
+        self.assertGreaterEqual(u'ant', 'ant')
+        self.assertLess('ant', u'bug')
+        self.assertLess(u'ant', 'bug')
+        self.assertLessEqual('ant', u'bug')
+        self.assertLessEqual(u'ant', 'bug')
+        self.assertLessEqual('ant', u'ant')
+        self.assertLessEqual(u'ant', 'ant')
+        self.assertRaises(self.failureException, self.assertGreater, 'ant', u'bug')
+        self.assertRaises(self.failureException, self.assertGreater, u'ant', 'bug')
+        self.assertRaises(self.failureException, self.assertGreater, 'ant', u'ant')
+        self.assertRaises(self.failureException, self.assertGreater, u'ant', 'ant')
+        self.assertRaises(self.failureException, self.assertGreaterEqual, 'ant',
+                          u'bug')
+        self.assertRaises(self.failureException, self.assertGreaterEqual, u'ant',
+                          'bug')
+        self.assertRaises(self.failureException, self.assertLess, 'bug', u'ant')
+        self.assertRaises(self.failureException, self.assertLess, u'bug', 'ant')
+        self.assertRaises(self.failureException, self.assertLess, 'ant', u'ant')
+        self.assertRaises(self.failureException, self.assertLess, u'ant', 'ant')
+        self.assertRaises(self.failureException, self.assertLessEqual, 'bug', u'ant')
+        self.assertRaises(self.failureException, self.assertLessEqual, u'bug', 'ant')
+
+    def testAssertMultiLineEqual(self):
+        sample_text = b"""\
+http://www.python.org/doc/2.3/lib/module-unittest.html
+test case
+    A test case is the smallest unit of testing. [...]
+"""
+        revised_sample_text = b"""\
+http://www.python.org/doc/2.4.1/lib/module-unittest.html
+test case
+    A test case is the smallest unit of testing. [...] You may provide your
+    own implementation that does not subclass from TestCase, of course.
+"""
+        sample_text_error = b"""
+- http://www.python.org/doc/2.3/lib/module-unittest.html
+?                             ^
++ http://www.python.org/doc/2.4.1/lib/module-unittest.html
+?                             ^^^
+  test case
+-     A test case is the smallest unit of testing. [...]
++     A test case is the smallest unit of testing. [...] You may provide your
+?                                                       +++++++++++++++++++++
++     own implementation that does not subclass from TestCase, of course.
+"""
+
+        for type_changer in (lambda x: x, lambda x: x.decode('utf8')):
+            try:
+                self.assertMultiLineEqual(type_changer(sample_text),
+                                          type_changer(revised_sample_text))
+            except self.failureException, e:
+                # no fair testing ourself with ourself, use assertEqual..
+                self.assertEqual(sample_text_error, str(e).encode('utf8'))
+
+    def testAssertIsNone(self):
+        self.assertIsNone(None)
+        self.assertRaises(self.failureException, self.assertIsNone, False)
+        self.assertIsNotNone('DjZoPloGears on Rails')
+        self.assertRaises(self.failureException, self.assertIsNotNone, None)
+
+    def testAssertRegexpMatches(self):
+        self.assertRegexpMatches('asdfabasdf', r'ab+')
+        self.assertRaises(self.failureException, self.assertRegexpMatches,
+                          'saaas', r'aaaa')
+
+    def testAssertRaisesRegexp(self):
+        class ExceptionMock(Exception):
+            pass
+
+        def Stub():
+            raise ExceptionMock('We expect')
+
+        self.assertRaisesRegexp(ExceptionMock, re.compile('expect$'), Stub)
+        self.assertRaisesRegexp(ExceptionMock, 'expect$', Stub)
+        self.assertRaisesRegexp(ExceptionMock, u'expect$', Stub)
+
+    def testAssertNotRaisesRegexp(self):
+        self.assertRaisesRegexp(
+                self.failureException, '^Exception not raised$',
+                self.assertRaisesRegexp, Exception, re.compile('x'),
+                lambda: None)
+        self.assertRaisesRegexp(
+                self.failureException, '^Exception not raised$',
+                self.assertRaisesRegexp, Exception, 'x',
+                lambda: None)
+        self.assertRaisesRegexp(
+                self.failureException, '^Exception not raised$',
+                self.assertRaisesRegexp, Exception, u'x',
+                lambda: None)
+
+    def testAssertRaisesRegexpMismatch(self):
+        def Stub():
+            raise Exception('Unexpected')
+
+        self.assertRaisesRegexp(
+                self.failureException,
+                r'"\^Expected\$" does not match "Unexpected"',
+                self.assertRaisesRegexp, Exception, '^Expected$',
+                Stub)
+        self.assertRaisesRegexp(
+                self.failureException,
+                r'"\^Expected\$" does not match "Unexpected"',
+                self.assertRaisesRegexp, Exception, u'^Expected$',
+                Stub)
+        self.assertRaisesRegexp(
+                self.failureException,
+                r'"\^Expected\$" does not match "Unexpected"',
+                self.assertRaisesRegexp, Exception,
+                re.compile('^Expected$'), Stub)
+
 
 class Test_TestSkipping(TestCase):
 
@@ -2386,20 +2756,20 @@ class Test_Assertions(TestCase):
     def test_AlmostEqual(self):
         self.failUnlessAlmostEqual(1.00000001, 1.0)
         self.failIfAlmostEqual(1.0000001, 1.0)
-        self.assertRaises(AssertionError,
+        self.assertRaises(self.failureException,
                           self.failUnlessAlmostEqual, 1.0000001, 1.0)
-        self.assertRaises(AssertionError,
+        self.assertRaises(self.failureException,
                           self.failIfAlmostEqual, 1.00000001, 1.0)
 
         self.failUnlessAlmostEqual(1.1, 1.0, places=0)
-        self.assertRaises(AssertionError,
+        self.assertRaises(self.failureException,
                           self.failUnlessAlmostEqual, 1.1, 1.0, places=1)
 
         self.failUnlessAlmostEqual(0, .1+.1j, places=0)
         self.failIfAlmostEqual(0, .1+.1j, places=1)
-        self.assertRaises(AssertionError,
+        self.assertRaises(self.failureException,
                           self.failUnlessAlmostEqual, 0, .1+.1j, places=1)
-        self.assertRaises(AssertionError,
+        self.assertRaises(self.failureException,
                           self.failIfAlmostEqual, 0, .1+.1j, places=0)
 
     def test_assertRaises(self):
@@ -2409,7 +2779,7 @@ class Test_Assertions(TestCase):
         self.assertRaises(KeyError, _raise, KeyError("key"))
         try:
             self.assertRaises(KeyError, lambda: None)
-        except AssertionError as e:
+        except self.failureException as e:
             self.assert_("KeyError not raised" in e, str(e))
         else:
             self.fail("assertRaises() didn't fail")
@@ -2426,7 +2796,7 @@ class Test_Assertions(TestCase):
         try:
             with self.assertRaises(KeyError):
                 pass
-        except AssertionError as e:
+        except self.failureException as e:
             self.assert_("KeyError not raised" in e, str(e))
         else:
             self.fail("assertRaises() didn't fail")