Tests: cli: Detect and handle the `-d ''` case

tests/test_cli.py

@@ -139,7 +139,19 @@ class CommandLineTestCase(unittest.TestCase):
         self.assertEqual(ctx.exception.code, -1)
 
         out, err = sys.stdout.getvalue(), sys.stderr.getvalue()
-        self.assertRegexpMatches(out + err, r'^invalid config')
+        self.assertEqual(out, '')
+        self.assertRegexpMatches(err, r'^invalid config: no such rule')
+
+    def test_run_with_empty_config(self):
+        sys.stdout, sys.stderr = StringIO(), StringIO()
+        with self.assertRaises(SystemExit) as ctx:
+            cli.run(('-d', '', 'file'))
+
+        self.assertEqual(ctx.exception.code, -1)
+
+        out, err = sys.stdout.getvalue(), sys.stderr.getvalue()
+        self.assertEqual(out, '')
+        self.assertRegexpMatches(err, r'^invalid config: not a dict')
 
     def test_run_version(self):
         sys.stdout, sys.stderr = StringIO(), StringIO()

yamllint/cli.py

@@ -88,7 +88,7 @@ def run(argv=None):
 
     try:
         if args.config_data is not None:
-            if ':' not in args.config_data:
+            if args.config_data != '' and ':' not in args.config_data:
                 args.config_data = 'extends: ' + args.config_data
             conf = YamlLintConfig(content=args.config_data)
         elif args.config_file is not None:

yamllint/config.py

@@ -59,6 +59,9 @@ class YamlLintConfig(object):
         except Exception as e:
             raise YamlLintConfigError('invalid config: %s' % e)
 
+        if type(conf) != dict:
+            raise YamlLintConfigError('invalid config: not a dict')
+
         self.rules = conf.get('rules', {})
 
         # Does this conf override another conf that we need to load?