Merge pull request #264 from kozaka-tv/261-in-collection_utilsset_of_…

…the_tuples_from_the_first_position-return-an-empty-set

#261 now on, always a set is returned

modules/database/db_manager.py

@@ -4,7 +4,7 @@
 
 from modules.song_loader.song_data import SongData
 from utils import string_utils
-from utils.collection_utils import set_of_the_tuples_from_the_first_position
+from utils.collection_utils import get_tuples_from_the_first_position_of
 from utils.string_utils import remove_special_chars
 
 log = logging.getLogger()
@@ -44,7 +44,7 @@ def __get_songs_from_db(self, artist, title):
         cur = self.db.cursor()
         songs = cur.execute("SELECT distinct colFileName FROM songs where colArtist like ? and colTitle like ?",
                             ("%" + artist + "%", "%" + title + "%")).fetchall()
-        return set_of_the_tuples_from_the_first_position(songs)
+        return get_tuples_from_the_first_position_of(songs)
 
     def search_song_by_artist_and_title(self, artist, title):
         songs_from_db_without_special_chars = self.__get_songs_from_db(remove_special_chars(artist),
@@ -87,8 +87,8 @@ def insert_song(self, song_data):
 
     def all_song_filenames(self):
         cur = self.db.cursor()
-        all_elements_tuple = cur.execute("SELECT distinct colFileName FROM songs").fetchall()
-        return set_of_the_tuples_from_the_first_position(all_elements_tuple)
+        all_songs = cur.execute("SELECT distinct colFileName FROM songs").fetchall()
+        return get_tuples_from_the_first_position_of(all_songs)
 
     def delete_song_by_filename(self, to_delete):
         cur = self.db.cursor()

tests/utils/test_collection_utils.py

@@ -31,41 +31,50 @@ def test_is_not_empty(test_input, expected):
     assert collection_utils.is_not_empty(test_input) == expected
 
 
-def test_set_of_the_tuples_from_the_first_position__with_none():
+def test_get_tuples_from_the_first_position_of__with_none():
     tuple_to_test = None
 
-    actual = collection_utils.set_of_the_tuples_from_the_first_position(tuple_to_test)
+    # noinspection PyTypeChecker
+    actual = collection_utils.get_tuples_from_the_first_position_of(tuple_to_test)
 
-    assert actual is None
+    assert len(actual) == 0
 
 
-def test_set_of_the_tuples_from_the_first_position__with_an_empty_list_input():
+def test_get_tuples_from_the_first_position_of__with_an_empty_list_input():
     tuple_to_test = []
 
-    actual = collection_utils.set_of_the_tuples_from_the_first_position(tuple_to_test)
+    actual = collection_utils.get_tuples_from_the_first_position_of(tuple_to_test)
 
     assert len(actual) == 0
 
 
-def test_set_of_the_tuples_from_the_first_position__with_1_tuple_and_string_in_the_first_position():
+def test_get_tuples_from_the_first_position_of__with_1_tuple_and_string_in_the_first_position__type_is_set():
+    test_input = [('first tuple 1st', 'first tuple 2nd', 'first tuple 3rd')]
+
+    actual = collection_utils.get_tuples_from_the_first_position_of(test_input)
+
+    assert isinstance(actual, set)
+
+
+def test_get_tuples_from_the_first_position_of__with_1_tuple_and_string_in_the_first_position():
     test_input = [('first tuple 1st', 'first tuple 2nd', 'first tuple 3rd')]
     expected = {'first tuple 1st'}
 
-    actual = collection_utils.set_of_the_tuples_from_the_first_position(test_input)
+    actual = collection_utils.get_tuples_from_the_first_position_of(test_input)
 
     assert actual == expected
 
 
-def test_set_of_the_tuples_from_the_first_position__with_1_tuple_and_int_in_the_first_position():
+def test_get_tuples_from_the_first_position_of__with_1_tuple_and_int_in_the_first_position():
     test_input = [(1, 'first tuple 2nd', 'first tuple 3rd')]
     expected = {1}
 
-    actual = collection_utils.set_of_the_tuples_from_the_first_position(test_input)
+    actual = collection_utils.get_tuples_from_the_first_position_of(test_input)
 
     assert actual == expected
 
 
-def test_set_of_the_tuples_from_the_first_position__with_2_tuples_and_string_in_the_first_position():
+def test_get_tuples_from_the_first_position_of__with_2_tuples_and_string_in_the_first_position():
     test_input = [
         ('first tuple 1st', 'first tuple 2nd', 'first tuple 3rd'),
         ('second tuple 1st', 'second tuple 2nd', 'second tuple 3rd'),
@@ -75,19 +84,19 @@ def test_set_of_the_tuples_from_the_first_position__with_2_tuples_and_string_in_
         'second tuple 1st',
     }
 
-    actual = collection_utils.set_of_the_tuples_from_the_first_position(test_input)
+    actual = collection_utils.get_tuples_from_the_first_position_of(test_input)
 
     assert actual == expected
 
 
-def test_set_of_the_tuples_from_the_first_position__with_2_tuples_and_int_in_the_first_position():
+def test_get_tuples_from_the_first_position_of__with_2_tuples_and_int_in_the_first_position():
     test_input = [
         (1, 'first tuple 2nd', 'first tuple 3rd'),
         (2, 'second tuple 2nd', 'second tuple 3rd'),
     ]
     expected = {1, 2}
 
-    actual = collection_utils.set_of_the_tuples_from_the_first_position(test_input)
+    actual = collection_utils.get_tuples_from_the_first_position_of(test_input)
 
     assert actual == expected
 

utils/collection_utils.py

@@ -9,10 +9,10 @@ def is_not_empty(collection):
     return bool(collection)
 
 
-def set_of_the_tuples_from_the_first_position(tuples):
-    if tuples is None:
-        return None
-    return {item[0] for item in tuples}
+def get_tuples_from_the_first_position_of(list_of_tuples: list[tuple]) -> set:
+    if list_of_tuples is None:
+        return set()
+    return {item[0] for item in list_of_tuples}
 
 
 def repr_in_multi_line(collection):