Don't run with no tests

Running with no tests is meaningless. It's also likely an issue with
installation and should be communicated clearly.

Closes-bug: 1472922
Change-Id: I951ee7862dd90c03ea19895bb0201d4622ee6f91

bandit/bandit.py

@@ -142,6 +142,12 @@ def main():
             )
             sys.exit(2)
 
+    # no point running if there are no tests available
+    if not b_mgr.has_tests:
+        logger.error('Could not find any tests to apply, please check '
+                     'the configuration.')
+        sys.exit(2)
+
     # initiate file discovery step within Bandit Manager
     b_mgr.discover_files(args.targets, args.recursive)
 

bandit/core/manager.py

@@ -81,6 +81,10 @@ class BanditManager():
         self.progress = self.b_conf.get_setting('progress')
         self.scores = []
 
+    @property
+    def has_tests(self):
+        return self.b_ts.has_tests
+
     @property
     def get_logger(self):
         return self.logger

bandit/core/test_set.py

@@ -213,3 +213,7 @@ class BanditTestSet():
         self.logger.debug('get_tests returning scoped_tests : %s',
                           scoped_tests)
         return scoped_tests
+
+    @property
+    def has_tests(self):
+        return bool(self.tests)