Implement of logic for the only_n_last_entities

podcast_downloader/__main__.py

@@ -26,8 +26,8 @@
     flatten_rss_links_data,
     get_raw_rss_entries_from_web,
     limit_file_name,
-    only_last_entity,
     only_entities_from_date,
+    only_last_n_entities,
 )
 
 
@@ -78,7 +78,7 @@ def configuration_to_function_on_empty_directory(
     configuration_value: str,
 ) -> Callable[[Iterable[RSSEntity]], Iterable[RSSEntity]]:
     if configuration_value == "download_last":
-        return only_last_entity
+        return partial(only_last_n_entities, 1)
 
     if configuration_value == "download_all_from_feed":
         return lambda source: source
@@ -90,6 +90,11 @@ def configuration_to_function_on_empty_directory(
         from_date = get_n_age_date(int(from_n_day_match[1]), local_time)
         return only_entities_from_date(from_date)
 
+    last_n_episodes = re.match(r"^download_last_(\d+)_episodes", configuration_value)
+    if last_n_episodes:
+        download_limit = int(last_n_episodes[1])
+        return partial(only_last_n_entities, download_limit)
+
     from_nth_day_match = re.match(r"^download_from_(.*)", configuration_value)
     if from_nth_day_match:
         day_label = parse_day_label(from_nth_day_match[1])

podcast_downloader/rss.py

@@ -110,8 +110,10 @@ def build_only_new_entities(
     )
 
 
-def only_last_entity(raw_rss_entries: Iterator[RSSEntity]) -> Iterator[RSSEntity]:
-    return islice(raw_rss_entries, 1)
+def only_last_n_entities(
+    n: int, raw_rss_entries: Iterator[RSSEntity]
+) -> Iterator[RSSEntity]:
+    return islice(raw_rss_entries, n)
 
 
 def is_entity_newer(from_date: time.struct_time, entity: RSSEntity) -> bool:

tests/only_n_last_entities_test.py

@@ -0,0 +1,36 @@
+import unittest
+
+from podcast_downloader.rss import only_last_n_entities
+from commons import rss_entity_generator
+
+
+class TestOnlyNLastRSSEntity(unittest.TestCase):
+    def test_get_only_last_n_rss_entities_happy_path(self):
+        # Assign
+        entity_1, entity_2, entity_3, entity_4, entity_5 = rss_entity_generator(limit=5)
+
+        rss_entities = [entity_1, entity_2, entity_3, entity_4, entity_5]
+        expected = [entity_1, entity_2]
+
+        # Act
+        result = list(only_last_n_entities(2, rss_entities))
+
+        # Assert
+        self.assertSequenceEqual(
+            result, expected, "Only the last entity should be return as result"
+        )
+
+    def test_get_only_last_n_rss_entities_less_than_required(self):
+        # Assign
+        entity_1 = rss_entity_generator(limit=1)
+
+        rss_entities = [entity_1]
+        expected = [entity_1]
+
+        # Act
+        result = list(only_last_n_entities(2, rss_entities))
+
+        # Assert
+        self.assertSequenceEqual(
+            result, expected, "Only the last entity should be return as result"
+        )