Prioritize existing flavor in meta format mapper

fimfarchive/mappers.py

@@ -31,6 +31,7 @@ from arrow import api as arrow, Arrow
 from fimfarchive.exceptions import InvalidStoryError
 from fimfarchive.flavors import MetaFormat
 from fimfarchive.stories import Story
+from fimfarchive.utils import find_flavor
 
 
 __all__ = (
@@ -128,9 +129,13 @@ class MetaFormatMapper(Mapper[Optional[MetaFormat]]):
     }
 
     def __call__(self, story: Story) -> Optional[MetaFormat]:
+        flavor = find_flavor(story, MetaFormat)
+
+        if flavor:
+            return flavor
+
         items = self.spec.items()
         meta = set(story.meta.keys())
-
         matches = {fmt for fmt, spec in items if spec & meta}
 
         if len(matches) == 1:

tests/test_mappers.py

@@ -334,3 +334,12 @@ class TestMetaFormatMapper:
         """
         story = self.merge(story, alpha, beta)
         assert mapper(story) is None
+
+    def test_existing_flavor(self, mapper, story, beta):
+        """
+        Tests existing flavor takes precedence over meta.
+        """
+        story = story.merge(flavors=[MetaFormat.ALPHA])
+        story = self.merge(story, beta, 'misc')
+
+        assert mapper(story) is MetaFormat.ALPHA