0.4.2 - Add more safety and improve test coverage (#9)

* Add argument safety to several public methods

* Implement test for non existing tag in PGN file tags

pypgn/game.py

@@ -24,13 +24,23 @@ class Game:
     def __init__(self, path: str = None):
         """
 
-        :param path: path to pgn file or Lichess game ID or
+        :param path: path to pgn file or Lichess game ID
         :type path: str
         """
-        self.pgn: list = _get_pgn_list(path)
+        if path is not None:
+            self.pgn: list = _get_pgn_list(path)
+        else:
+            self.pgn = None
         self.tags: dict = _get_tags(self.pgn)
         self.moves: List[Move] = _get_moves(self.pgn)
 
+    def open_pgn(self, path: str) -> None:
+        """Sets the pgn attribute
+
+        :param path: path to pgn file or Lichess game ID
+        """
+        self.pgn = _get_pgn_list(path)
+
     def get_pgn_list(self) -> list:
         """Gets and returns a list of lines of the PGN
 
@@ -47,7 +57,10 @@ def get_tag(self, name: str) -> str:
         :return: Value of a tag
         :rtype: str
         """
-        return self.tags[name]
+        if name in self.tags:
+            return self.tags[name]
+        else:
+            raise KeyError(f"This tag does not exist: {name}")
 
     def get_tags(self) -> dict:
         """Gets and returns a map of metadata tags of the PGN
@@ -108,13 +121,13 @@ def get_date(self) -> str:
 
         :return: Date of the game in format YYYY.MM.DD
         """
-        return self.get_tag('Date')
+        return self.get_tag('Date' if 'Date' in self.tags else 'UTCDate')
 
-    def get_move_range(self, start: int, end: int) -> List[Move]:
+    def get_move_range(self, start: int = 1, end: int = None) -> List[Move]:
         """Gets and returns a range of moves
 
         :param start: Start index of moves to get
         :param end: End index of moves to get
         :return: List of moves in given range
         """
-        return self.moves[start - 1:end]
+        return self.moves[start - 1:(end if end is not None else -1)]

pypgn/game_utils.py

@@ -29,6 +29,7 @@ def _get_tags(pgn: list) -> dict:
 
 
 def _get_moves(pgn: list) -> List[Move]:
+    movetext = ''
     for line in pgn:
         if re.search(r'^1\. ', line):
             movetext: str = line

test/test_game.py

@@ -19,11 +19,15 @@ def test_get_pgn_list(self, game_pgn):
     def test_get_tags(self, game_pgn):
         assert type(game_pgn.get_tags()) == dict
 
-    def test_get_tag_value(self, game_pgn):
+    def test_get_tag(self, game_pgn):
         assert game_pgn.get_tag('Event') == "Rated Blitz game"
         assert game_pgn.get_tag('Site') == "https://lichess.org/#"
         assert game_pgn.get_tag('UTCDate') == "2019.11.06"
 
+    def test_get_non_existing_tag(self, game_pgn):
+        with pytest.raises(KeyError):
+            game_pgn.get_tag('SomeTag')
+
     def test_get_move(self, game_pgn):
         assert game_pgn.get_move(4) == ["4.", "d4", "Nc6"]
 
@@ -35,8 +39,7 @@ def test_get_moves(self, game_pgn):
     def test_get_ply(self, game_pgn):
         for i in range(1, game_pgn.get_move_count()):
             move = game_pgn.get_move(i)
-            assert move[1] == game_pgn.get_ply(i, 'w') \
-                   and move[2] == game_pgn.get_ply(i, 'b'), \
+            assert move[1] == game_pgn.get_ply(i, 'w') and move[2] == game_pgn.get_ply(i, 'b'), \
                 "Non-matching ply pair at move %s !" % str(i)
 
     def test_get_move_count(self, game_pgn):