Add tests for raise translation and raise_() functionality.

1. Uncomment the Test_raise tests now that support for tracebacks has been
added. Add test_unknown_value() to test for #455.

2. Run the test_raise_() test now that #455 is fixed. Add a test for #387
(raise_(E, V, T) now detects if V is an instance of E and no longer blindly
calls E(V)).

Author: vermaport

tests/test_future/test_libfuturize_fixers.py

@@ -702,133 +702,140 @@ def test_with_future_print_function(self):
 #             except (Exception, SystemExit):
 #                 pass"""
 #         self.unchanged(s)
-#
-# class Test_raise(FixerTestCase):
-#     fixer = "raise"
-#
-#     def test_basic(self):
-#         b = """raise Exception, 5"""
-#         a = """raise Exception(5)"""
-#         self.check(b, a)
-#
-#     def test_prefix_preservation(self):
-#         b = """raise Exception,5"""
-#         a = """raise Exception(5)"""
-#         self.check(b, a)
-#
-#         b = """raise   Exception,    5"""
-#         a = """raise   Exception(5)"""
-#         self.check(b, a)
-#
-#     def test_with_comments(self):
-#         b = """raise Exception, 5 # foo"""
-#         a = """raise Exception(5) # foo"""
-#         self.check(b, a)
-#
-#         b = """raise E, (5, 6) % (a, b) # foo"""
-#         a = """raise E((5, 6) % (a, b)) # foo"""
-#         self.check(b, a)
-#
-#         b = """def foo():
-#                     raise Exception, 5, 6 # foo"""
-#         a = """def foo():
-#                     raise Exception(5).with_traceback(6) # foo"""
-#         self.check(b, a)
-#
-#     def test_None_value(self):
-#         b = """raise Exception(5), None, tb"""
-#         a = """raise Exception(5).with_traceback(tb)"""
-#         self.check(b, a)
-#
-#     def test_tuple_value(self):
-#         b = """raise Exception, (5, 6, 7)"""
-#         a = """raise Exception(5, 6, 7)"""
-#         self.check(b, a)
-#
-#     def test_tuple_detection(self):
-#         b = """raise E, (5, 6) % (a, b)"""
-#         a = """raise E((5, 6) % (a, b))"""
-#         self.check(b, a)
-#
-#     def test_tuple_exc_1(self):
-#         b = """raise (((E1, E2), E3), E4), V"""
-#         a = """raise E1(V)"""
-#         self.check(b, a)
-#
-#     def test_tuple_exc_2(self):
-#         b = """raise (E1, (E2, E3), E4), V"""
-#         a = """raise E1(V)"""
-#         self.check(b, a)
-#
-#     # These should produce a warning
-#
-#     def test_string_exc(self):
-#         s = """raise 'foo'"""
-#         self.warns_unchanged(s, "Python 3 does not support string exceptions")
-#
-#     def test_string_exc_val(self):
-#         s = """raise "foo", 5"""
-#         self.warns_unchanged(s, "Python 3 does not support string exceptions")
-#
-#     def test_string_exc_val_tb(self):
-#         s = """raise "foo", 5, 6"""
-#         self.warns_unchanged(s, "Python 3 does not support string exceptions")
-#
-#     # These should result in traceback-assignment
-#
-#     def test_tb_1(self):
-#         b = """def foo():
-#                     raise Exception, 5, 6"""
-#         a = """def foo():
-#                     raise Exception(5).with_traceback(6)"""
-#         self.check(b, a)
-#
-#     def test_tb_2(self):
-#         b = """def foo():
-#                     a = 5
-#                     raise Exception, 5, 6
-#                     b = 6"""
-#         a = """def foo():
-#                     a = 5
-#                     raise Exception(5).with_traceback(6)
-#                     b = 6"""
-#         self.check(b, a)
-#
-#     def test_tb_3(self):
-#         b = """def foo():
-#                     raise Exception,5,6"""
-#         a = """def foo():
-#                     raise Exception(5).with_traceback(6)"""
-#         self.check(b, a)
-#
-#     def test_tb_4(self):
-#         b = """def foo():
-#                     a = 5
-#                     raise Exception,5,6
-#                     b = 6"""
-#         a = """def foo():
-#                     a = 5
-#                     raise Exception(5).with_traceback(6)
-#                     b = 6"""
-#         self.check(b, a)
-#
-#     def test_tb_5(self):
-#         b = """def foo():
-#                     raise Exception, (5, 6, 7), 6"""
-#         a = """def foo():
-#                     raise Exception(5, 6, 7).with_traceback(6)"""
-#         self.check(b, a)
-#
-#     def test_tb_6(self):
-#         b = """def foo():
-#                     a = 5
-#                     raise Exception, (5, 6, 7), 6
-#                     b = 6"""
-#         a = """def foo():
-#                     a = 5
-#                     raise Exception(5, 6, 7).with_traceback(6)
-#                     b = 6"""
-#         self.check(b, a)
+
+class Test_raise(FixerTestCase):
+    fixer = "raise"
+
+    def test_basic(self):
+        b = """raise Exception, 5"""
+        a = """raise Exception(5)"""
+        self.check(b, a)
+
+    def test_prefix_preservation(self):
+        b = """raise Exception,5"""
+        a = """raise Exception(5)"""
+        self.check(b, a)
+
+        b = """raise   Exception,    5"""
+        a = """raise   Exception(5)"""
+        self.check(b, a)
+
+    def test_with_comments(self):
+        b = """raise Exception, 5 # foo"""
+        a = """raise Exception(5) # foo"""
+        self.check(b, a)
+
+        b = """def foo():
+                    raise Exception, 5, 6 # foo"""
+        a = """def foo():
+                    raise Exception(5).with_traceback(6) # foo"""
+        self.check(b, a)
+
+    def test_None_value(self):
+        b = """raise Exception(5), None, tb"""
+        a = """raise Exception(5).with_traceback(tb)"""
+        self.check(b, a)
+
+    def test_tuple_value(self):
+        b = """raise Exception, (5, 6, 7)"""
+        a = """raise Exception(5, 6, 7)"""
+        self.check(b, a)
+
+    def test_tuple_exc_1(self):
+        b = """raise (((E1, E2), E3), E4), 5"""
+        a = """raise E1(5)"""
+        self.check(b, a)
+
+    def test_tuple_exc_2(self):
+        b = """raise (E1, (E2, E3), E4), 5"""
+        a = """raise E1(5)"""
+        self.check(b, a)
+
+    def test_unknown_value(self):
+        b = """
+        raise E, V"""
+        a = """
+        from future.utils import raise_
+        raise_(E, V)"""
+        self.check(b, a)
+
+    def test_unknown_value_with_traceback_with_comments(self):
+        b = """
+        raise E, Func(arg1, arg2, arg3), tb # foo"""
+        a = """
+        from future.utils import raise_
+        raise_(E, Func(arg1, arg2, arg3), tb) # foo"""
+        self.check(b, a)
+
+    # These should produce a warning
+
+    def test_string_exc(self):
+        s = """raise 'foo'"""
+        self.warns_unchanged(s, "Python 3 does not support string exceptions")
+
+    def test_string_exc_val(self):
+        s = """raise "foo", 5"""
+        self.warns_unchanged(s, "Python 3 does not support string exceptions")
+
+    def test_string_exc_val_tb(self):
+        s = """raise "foo", 5, 6"""
+        self.warns_unchanged(s, "Python 3 does not support string exceptions")
+
+    # These should result in traceback-assignment
+
+    def test_tb_1(self):
+        b = """def foo():
+                    raise Exception, 5, 6"""
+        a = """def foo():
+                    raise Exception(5).with_traceback(6)"""
+        self.check(b, a)
+
+    def test_tb_2(self):
+        b = """def foo():
+                    a = 5
+                    raise Exception, 5, 6
+                    b = 6"""
+        a = """def foo():
+                    a = 5
+                    raise Exception(5).with_traceback(6)
+                    b = 6"""
+        self.check(b, a)
+
+    def test_tb_3(self):
+        b = """def foo():
+                    raise Exception,5,6"""
+        a = """def foo():
+                    raise Exception(5).with_traceback(6)"""
+        self.check(b, a)
+
+    def test_tb_4(self):
+        b = """def foo():
+                    a = 5
+                    raise Exception,5,6
+                    b = 6"""
+        a = """def foo():
+                    a = 5
+                    raise Exception(5).with_traceback(6)
+                    b = 6"""
+        self.check(b, a)
+
+    def test_tb_5(self):
+        b = """def foo():
+                    raise Exception, (5, 6, 7), 6"""
+        a = """def foo():
+                    raise Exception(5, 6, 7).with_traceback(6)"""
+        self.check(b, a)
+
+    def test_tb_6(self):
+        b = """def foo():
+                    a = 5
+                    raise Exception, (5, 6, 7), 6
+                    b = 6"""
+        a = """def foo():
+                    a = 5
+                    raise Exception(5, 6, 7).with_traceback(6)
+                    b = 6"""
+        self.check(b, a)
 #
 # class Test_throw(FixerTestCase):
 #     fixer = "throw"

tests/test_future/test_utils.py

@@ -110,11 +110,7 @@ def test_isbytes(self):
         self.assertFalse(isbytes(self.s))
         self.assertFalse(isbytes(self.s2))
 
-    @unittest.skipIf(PY3, 'test_raise_ currently fails on Py3')
     def test_raise_(self):
-        """
-        The with_value() test currently fails on Py3
-        """
         def valerror():
             try:
                 raise ValueError("Apples!")
@@ -173,6 +169,23 @@ def bar():
             pass
         # incorrectly raises a TypeError on Py3 as of v0.15.2.
 
+    def test_raise_custom_exception(self):
+        """
+        Test issue #387.
+        """
+        class CustomException(Exception):
+            def __init__(self, severity, message):
+                super().__init__("custom message of severity %d: %s" % (
+                    severity, message))
+
+        def raise_custom_exception():
+            try:
+                raise CustomException(1, "hello")
+            except CustomException:
+                raise_(*sys.exc_info())
+
+        self.assertRaises(CustomException, raise_custom_exception)
+
     @skip26
     def test_as_native_str(self):
         """