test to check that the right Builds flag values get removed

tests/rewritemeta.TestCase

@@ -115,6 +115,25 @@ class RewriteMetaTest(unittest.TestCase):
             [{'versionCode': 0}],
         )
 
+    def test_remove_blank_flags_from_builds_values_to_purge(self):
+        self.assertEqual(
+            rewritemeta.remove_blank_flags_from_builds(
+                [
+                    {
+                        'antifeatures': dict(),
+                        'forceversion': False,
+                        'init': None,
+                        'rm': '',
+                        'scandelete': list(),
+                        'versionCode': 0,
+                    },
+                    {'antifeatures': list(), 'versionCode': 1},
+                    {'antifeatures': '', 'versionCode': 2},
+                ]
+            ),
+            [{'versionCode': 0}, {'versionCode': 1}, {'versionCode': 2}],
+        )
+
     def test_rewrite_no_builds(self):
         os.chdir(self.testdir)
         Path('metadata').mkdir()