From 6030c80ee02bf9710523d39028b41dc8587f0478 Mon Sep 17 00:00:00 2001
From: Marc Wouts <marc.wouts@gmail.com>
Date: Tue, 23 Oct 2018 21:41:26 +0200
Subject: [PATCH] Test metadata filtering

#105 #106 #110
---
 jupytext/metadata_filter.py   | 54 +++++++++++++++++------------------
 tests/test_metadata_filter.py | 28 ++++++++++++++++++
 2 files changed, 55 insertions(+), 27 deletions(-)
 create mode 100644 tests/test_metadata_filter.py

diff --git a/jupytext/metadata_filter.py b/jupytext/metadata_filter.py
index 996ef53ca..c3f28af0f 100644
--- a/jupytext/metadata_filter.py
+++ b/jupytext/metadata_filter.py
@@ -1,45 +1,45 @@
 """Notebook and cell metadata filtering"""
 
 
-def parse_metadata_config(metadata_config):
+def parse_metadata_config(metadata_config, actual_keys, filtered_keys=None):
     """Return additional and excluded sets that correspond to a config of the form
     'entry_one,entry_two-negative_entry_one,negative_entry_two"""
-    if not metadata_config:
-        return set(), set()
-
-    if isinstance(metadata_config, list):
-        return set(metadata_config), set()
-
-    if isinstance(metadata_config, tuple):
-        additional, excluded = metadata_config
-        return set(additional), set(excluded)
+    if metadata_config is True:
+        metadata_config = 'all'
+    elif metadata_config is False:
+        metadata_config = '-all'
+    elif metadata_config is None:
+        metadata_config = ''
 
     if '-' in metadata_config:
         additional, excluded = metadata_config.split('-', 1)
-        additional = additional.split(',')
-        excluded = excluded.split(',')
-        return set(additional), set(excluded)
+        excluded = set(excluded.split(',')).difference({''})
+        if not additional and 'all' not in excluded:
+            additional = set(filtered_keys or actual_keys)
+        else:
+            additional = set(additional.split(',')).difference({''})
+    else:
+        additional = set(metadata_config.split(',')).difference({''})
+        excluded = set()
+
+    if 'all' in additional:
+        additional = actual_keys
+    if 'all' in excluded:
+        excluded = actual_keys.difference(additional)
 
-    additional = metadata_config.split(',')
-    return set(additional), set()
+    return additional, excluded
 
 
 def filter_metadata(metadata, user_metadata_config, default_metadata_config):
     """Filter the cell or notebook metadata, according to the user preference"""
-    if user_metadata_config is True:
-        return metadata
-
-    if user_metadata_config is False:
-        return {}
-
     actual_keys = set(metadata.keys())
-    default_positive, default_negative = parse_metadata_config(default_metadata_config)
-    user_positive, user_negative = parse_metadata_config(user_metadata_config)
+    default_positive, default_negative = parse_metadata_config(default_metadata_config, actual_keys)
+    user_positive, user_negative = parse_metadata_config(
+        user_metadata_config, actual_keys,
+        actual_keys.intersection(default_positive).difference(default_negative))
 
-    if not default_positive:
-        keep_keys = actual_keys.difference(default_negative.difference(user_positive)).difference(user_negative)
-    else:
-        keep_keys = actual_keys.intersection(default_positive.union(user_positive)).difference(user_negative)
+    keep_keys = actual_keys.intersection(default_positive.difference(user_negative).union(user_positive)) \
+        .difference(default_negative.difference(user_positive).union(user_negative))
 
     for key in actual_keys:
         if key not in keep_keys:
diff --git a/tests/test_metadata_filter.py b/tests/test_metadata_filter.py
new file mode 100644
index 000000000..a91b2742e
--- /dev/null
+++ b/tests/test_metadata_filter.py
@@ -0,0 +1,28 @@
+from jupytext.metadata_filter import filter_metadata
+
+
+def to_dict(keys):
+    return {key: None for key in keys}
+
+
+def test_metadata_filter_default():
+    assert filter_metadata(to_dict(['technical', 'user', 'preserve']), None, '-technical'
+                           ) == to_dict(['user', 'preserve'])
+    assert filter_metadata(to_dict(['technical', 'user', 'preserve']), None, 'preserve-all'
+                           ) == to_dict(['preserve'])
+
+
+def test_metadata_filter_user_plus_default():
+    assert filter_metadata(to_dict(['technical', 'user', 'preserve']), '-user', '-technical'
+                           ) == to_dict(['preserve'])
+    assert filter_metadata(to_dict(['technical', 'user', 'preserve']), 'all-user', '-technical'
+                           ) == to_dict(['preserve', 'technical'])
+    assert filter_metadata(to_dict(['technical', 'user', 'preserve']), 'user', 'preserve-all'
+                           ) == to_dict(['user', 'preserve'])
+
+
+def test_metadata_filter_user_overrides_default():
+    assert filter_metadata(to_dict(['technical', 'user', 'preserve']), 'all-user', '-technical'
+                           ) == to_dict(['technical', 'preserve'])
+    assert filter_metadata(to_dict(['technical', 'user', 'preserve']), 'user-all', 'preserve'
+                           ) == to_dict(['user'])