[1.10.x] Replaced use of TestCase.fail() with assertRaises().

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

Backport of c9ae09addffb839403312131d4251e9d8b454508 from master

3 files changed, 7 insertions, 16 deletions

diff --git a/tests/forms_tests/tests/test_error_messages.py b/tests/forms_tests/tests/test_error_messages.py
index 0632107e1e..315e72604d 100644
--- a/tests/forms_tests/tests/test_error_messages.py
+++ b/tests/forms_tests/tests/test_error_messages.py
@@ -16,11 +16,9 @@ from django.utils.safestring import mark_safe
 
 class AssertFormErrorsMixin(object):
     def assertFormErrors(self, expected, the_callable, *args, **kwargs):
-        try:
+        with self.assertRaises(ValidationError) as cm:
             the_callable(*args, **kwargs)
-            self.fail("Testing the 'clean' method on %s failed to raise a ValidationError.")
-        except ValidationError as e:
-            self.assertEqual(e.messages, expected)
+        self.assertEqual(cm.exception.messages, expected)
 
 
 class FormsErrorMessagesTestCase(SimpleTestCase, AssertFormErrorsMixin):
diff --git a/tests/forms_tests/tests/test_forms.py b/tests/forms_tests/tests/test_forms.py
index 89d8d6bb67..2bd49b7361 100644
--- a/tests/forms_tests/tests/test_forms.py
+++ b/tests/forms_tests/tests/test_forms.py
@@ -173,11 +173,9 @@ class FormsTestCase(SimpleTestCase):
         self.assertFalse(p.is_bound)
         self.assertEqual(p.errors, {})
         self.assertFalse(p.is_valid())
-        try:
+        with self.assertRaises(AttributeError):
             p.cleaned_data
-            self.fail('Attempts to access cleaned_data when validation fails should fail.')
-        except AttributeError:
-            pass
+
         self.assertHTMLEqual(
             str(p),
             """<tr><th><label for="id_first_name">First name:</label></th><td>
@@ -2168,11 +2166,9 @@ Password: <input type="password" name="password" required />
         self.assertEqual(p.errors['last_name'], ['This field is required.'])
         self.assertEqual(p.errors['birthday'], ['This field is required.'])
         self.assertEqual(p['first_name'].errors, ['This field is required.'])
-        try:
+        # Accessing a nonexistent field.
+        with self.assertRaises(KeyError):
             p['person1-first_name'].errors
-            self.fail('Attempts to access non-existent fields should fail.')
-        except KeyError:
-            pass
 
         # In this example, the data doesn't have a prefix, but the form requires it, so
         # the form doesn't "see" the fields.
diff --git a/tests/forms_tests/tests/test_formsets.py b/tests/forms_tests/tests/test_formsets.py
index f367d22397..d432a5d2d9 100644
--- a/tests/forms_tests/tests/test_formsets.py
+++ b/tests/forms_tests/tests/test_formsets.py
@@ -1012,11 +1012,8 @@ class FormsFormsetTestCase(SimpleTestCase):
 
         # confirm indexing of formset
         self.assertEqual(formset[0], forms[0])
-        try:
+        with self.assertRaises(IndexError):
             formset[3]
-            self.fail('Requesting an invalid formset index should raise an exception')
-        except IndexError:
-            pass
 
         # Formsets can override the default iteration order
         class BaseReverseFormSet(BaseFormSet):