Replaced use of TestCase.fail() with assertRaises().

Also removed try/except/fail antipattern that hides exceptions.

tests/urlpatterns_reverse/tests.py

@@ -5,7 +5,6 @@ Unit tests for reverse URL lookups.
 from __future__ import unicode_literals
 
 import sys
-import unittest
 
 from admin_scripts.tests import AdminScriptTestCase
 
@@ -313,16 +312,9 @@ class URLPatternReverse(SimpleTestCase):
 
     def test_patterns_reported(self):
         # Regression for #17076
-        try:
+        with self.assertRaisesMessage(NoReverseMatch, r"1 pattern(s) tried: ['people/(?P<name>\\w+)/$']"):
             # this url exists, but requires an argument
             reverse("people", args=[])
-        except NoReverseMatch as e:
-            pattern_description = r"1 pattern(s) tried: ['people/(?P<name>\\w+)/$']"
-            self.assertIn(pattern_description, str(e))
-        else:
-            # we can't use .assertRaises, since we want to inspect the
-            # exception
-            self.fail("Expected a NoReverseMatch, but none occurred.")
 
     @override_script_prefix('/script:name/')
     def test_script_name_escaping(self):
@@ -339,7 +331,7 @@ class URLPatternReverse(SimpleTestCase):
         )
 
 
-class ResolverTests(unittest.TestCase):
+class ResolverTests(SimpleTestCase):
     @ignore_warnings(category=RemovedInDjango20Warning)
     def test_resolver_repr(self):
         """
@@ -359,10 +351,7 @@ class ResolverTests(unittest.TestCase):
         urls = 'urlpatterns_reverse.named_urls'
         proxy_url = reverse_lazy('named-url1', urlconf=urls)
         resolver = get_resolver(urls)
-        try:
-            resolver.resolve(proxy_url)
-        except TypeError:
-            self.fail('Failed to coerce lazy object to text')
+        resolver.resolve(proxy_url)
 
     def test_resolver_reverse(self):
         resolver = get_resolver('urlpatterns_reverse.named_urls')
@@ -407,32 +396,31 @@ class ResolverTests(unittest.TestCase):
             [{'type': RegexURLResolver}, {'type': RegexURLPattern, 'name': None}],
             [{'type': RegexURLResolver}, {'type': RegexURLResolver}],
         ]
-        try:
+        with self.assertRaisesMessage(Resolver404, "tried") as cm:
             resolve('/included/non-existent-url', urlconf=urls)
-            self.fail('resolve did not raise a 404')
-        except Resolver404 as e:
-            # make sure we at least matched the root ('/') url resolver:
-            self.assertIn('tried', e.args[0])
-            tried = e.args[0]['tried']
-            self.assertEqual(
-                len(e.args[0]['tried']),
-                len(url_types_names),
-                'Wrong number of tried URLs returned.  Expected %s, got %s.' % (
-                    len(url_types_names), len(e.args[0]['tried'])
-                )
+        e = cm.exception
+        # make sure we at least matched the root ('/') url resolver:
+        self.assertIn('tried', e.args[0])
+        tried = e.args[0]['tried']
+        self.assertEqual(
+            len(e.args[0]['tried']),
+            len(url_types_names),
+            'Wrong number of tried URLs returned.  Expected %s, got %s.' % (
+                len(url_types_names), len(e.args[0]['tried'])
             )
-            for tried, expected in zip(e.args[0]['tried'], url_types_names):
-                for t, e in zip(tried, expected):
-                    self.assertIsInstance(t, e['type']), str('%s is not an instance of %s') % (t, e['type'])
-                    if 'name' in e:
-                        if not e['name']:
-                            self.assertIsNone(t.name, 'Expected no URL name but found %s.' % t.name)
-                        else:
-                            self.assertEqual(
-                                t.name,
-                                e['name'],
-                                'Wrong URL name.  Expected "%s", got "%s".' % (e['name'], t.name)
-                            )
+        )
+        for tried, expected in zip(e.args[0]['tried'], url_types_names):
+            for t, e in zip(tried, expected):
+                self.assertIsInstance(t, e['type']), str('%s is not an instance of %s') % (t, e['type'])
+                if 'name' in e:
+                    if not e['name']:
+                        self.assertIsNone(t.name, 'Expected no URL name but found %s.' % t.name)
+                    else:
+                        self.assertEqual(
+                            t.name,
+                            e['name'],
+                            'Wrong URL name.  Expected "%s", got "%s".' % (e['name'], t.name)
+                        )
 
     def test_namespaced_view_detail(self):
         resolver = get_resolver('urlpatterns_reverse.nested_urls')
@@ -918,17 +906,11 @@ class DefaultErrorHandlerTests(SimpleTestCase):
 
     def test_default_handler(self):
         "If the urls.py doesn't specify handlers, the defaults are used"
-        try:
-            response = self.client.get('/test/')
-            self.assertEqual(response.status_code, 404)
-        except AttributeError:
-            self.fail("Shouldn't get an AttributeError due to undefined 404 handler")
+        response = self.client.get('/test/')
+        self.assertEqual(response.status_code, 404)
 
-        try:
-            with self.assertRaises(ValueError):
-                self.client.get('/bad_view/')
-        except AttributeError:
-            self.fail("Shouldn't get an AttributeError due to undefined 500 handler")
+        with self.assertRaisesMessage(ValueError, "I don't think I'm getting good"):
+            self.client.get('/bad_view/')
 
 
 @override_settings(ROOT_URLCONF=None)