Added a few more test cases

Making sure multi-line empty dicts/arrays with and without comments
still properly pass when `forbid: non-empty` is set.

tests/rules/test_braces.py

@@ -68,6 +68,14 @@ class ColonTestCase(RuleTestCase):
                    '  a: 1\n', conf)
         self.check('---\n'
                    'dict: {}\n', conf)
+        self.check('---\n'
+                   'dict: {\n'
+                   '}\n', conf)
+        self.check('---\n'
+                   'dict: {\n'
+                   '# commented: value\n'
+                   '# another: value2\n'
+                   '}\n', conf)
         self.check('---\n'
                    'dict: {a}\n', conf, problem=(2, 8))
         self.check('---\n'

tests/rules/test_brackets.py

@@ -68,6 +68,13 @@ class ColonTestCase(RuleTestCase):
                    '  - b\n', conf)
         self.check('---\n'
                    'array: []\n', conf)
+        self.check('---\n'
+                   'array: [\n\n'
+                   ']\n', conf)
+        self.check('---\n'
+                   'array: [\n'
+                   '# a comment\n'
+                   ']\n', conf)
         self.check('---\n'
                    'array: [a, b]\n', conf, problem=(2, 9))
         self.check('---\n'