fix: correct no-prefix no-suffix exclude for top-level dirs

Resolves PyCQA#975

bandit/core/manager.py

@@ -216,9 +216,6 @@ def discover_files(self, targets, recursive=False, excluded_paths=""):
         # if there are command line provided exclusions add them to the list
         if excluded_paths:
             for path in excluded_paths.split(","):
-                if os.path.isdir(path):
-                    path = os.path.join(path, "*")
-
                 excluded_path_globs.append(path)
 
         # build list of files we will analyze

tests/unit/core/test_manager.py

@@ -255,25 +255,25 @@ def test_discover_files_exclude_dir(self, isdir):
         self.assertEqual(["./x/y.py"], self.manager.excluded_files)
 
         # Test exclude dir without wildcard
-        isdir.side_effect = [True, False]
+        isdir.side_effect = [False]
         self.manager.discover_files(["./x/y.py"], True, "./x/")
         self.assertEqual([], self.manager.files_list)
         self.assertEqual(["./x/y.py"], self.manager.excluded_files)
 
         # Test exclude dir without wildcard or trailing slash
-        isdir.side_effect = [True, False]
+        isdir.side_effect = [False]
         self.manager.discover_files(["./x/y.py"], True, "./x")
         self.assertEqual([], self.manager.files_list)
         self.assertEqual(["./x/y.py"], self.manager.excluded_files)
 
         # Test exclude top-level dir without prefix or suffix
-        isdir.side_effect = [True, False]
+        isdir.side_effect = [False]
         self.manager.discover_files(["./x/y/z.py"], True, "x")
         self.assertEqual([], self.manager.files_list)
         self.assertEqual(["./x/y/z.py"], self.manager.excluded_files)
 
         # Test exclude lower-level dir without prefix or suffix
-        isdir.side_effect = [False, False]
+        isdir.side_effect = [False]
         self.manager.discover_files(["./x/y/z.py"], True, "y")
         self.assertEqual([], self.manager.files_list)
         self.assertEqual(["./x/y/z.py"], self.manager.excluded_files)