bpo-46411: Modernize exception handling in tests

Lib/test/test_argparse.py

@@ -102,8 +102,8 @@ def stderr_to_parser_error(parse_args, *args, **kwargs):
                 if getattr(result, key) is sys.stderr:
                     setattr(result, key, old_stderr)
             return result
-        except SystemExit:
-            code = sys.exc_info()[1].code
+        except SystemExit as e:
+            code = e.code
             stdout = sys.stdout.getvalue()
             stderr = sys.stderr.getvalue()
             raise ArgumentParserError(
@@ -1850,8 +1850,7 @@ def __call__(self, parser, namespace, value, option_string=None):
                     raise AssertionError('value: %s' % value)
                 assert expected_ns == namespace, ('expected %s, got %s' %
                                                   (expected_ns, namespace))
-            except AssertionError:
-                e = sys.exc_info()[1]
+            except AssertionError as e:
                 raise ArgumentParserError('opt_action failed: %s' % e)
             setattr(namespace, 'spam', value)
 
@@ -1876,8 +1875,7 @@ def __call__(self, parser, namespace, value, option_string=None):
                     raise AssertionError('value: %s' % value)
                 assert expected_ns == namespace, ('expected %s, got %s' %
                                                   (expected_ns, namespace))
-            except AssertionError:
-                e = sys.exc_info()[1]
+            except AssertionError as e:
                 raise ArgumentParserError('arg_action failed: %s' % e)
             setattr(namespace, 'badger', value)
 

Lib/test/test_builtin.py

@@ -581,8 +581,8 @@ def __dir__(self):
         # dir(traceback)
         try:
             raise IndexError
-        except:
-            self.assertEqual(len(dir(sys.exc_info()[2])), 4)
+        except IndexError as e:
+            self.assertEqual(len(dir(e.__traceback__)), 4)
 
         # test that object has a __dir__()
         self.assertEqual(sorted([].__dir__()), dir([]))

Lib/test/test_inspect.py

@@ -135,8 +135,8 @@ def test_excluding_predicates(self):
         self.istest(inspect.iscode, 'mod.spam.__code__')
         try:
             1/0
-        except:
-            tb = sys.exc_info()[2]
+        except Exception as e:
+            tb = e.__traceback__
             self.istest(inspect.isframe, 'tb.tb_frame')
             self.istest(inspect.istraceback, 'tb')
             if hasattr(types, 'GetSetDescriptorType'):

Lib/test/test_logging.py

@@ -5524,8 +5524,8 @@ def test_compute_rollover(self, when=when, exp=exp):
                     print('currentSecond: %s' % currentSecond, file=sys.stderr)
                     print('r: %s' % r, file=sys.stderr)
                     print('result: %s' % result, file=sys.stderr)
-                except Exception:
-                    print('exception in diagnostic code: %s' % sys.exc_info()[1], file=sys.stderr)
+                except Exception as e:
+                    print('exception in diagnostic code: %s' % e, file=sys.stderr)
         self.assertEqual(exp, actual)
         rh.close()
     setattr(TimedRotatingFileHandlerTest, "test_compute_rollover_%s" % when, test_compute_rollover)

Lib/test/test_raise.py

@@ -12,8 +12,8 @@
 def get_tb():
     try:
         raise OSError()
-    except:
-        return sys.exc_info()[2]
+    except OSError as e:
+        return e.__traceback__
 
 
 class Context:

Lib/test/test_zipimport.py

@@ -710,8 +710,8 @@ def testDoctestSuite(self):
     def doTraceback(self, module):
         try:
             module.do_raise()
-        except:
-            tb = sys.exc_info()[2].tb_next
+        except Exception as e:
+            tb = e.__traceback__.tb_next
 
             f,lno,n,line = extract_tb(tb, 1)[0]
             self.assertEqual(line, raise_src.strip())