Add test for invalid LineCollection args

src/data_morph/shapes/bases/line_collection.py

@@ -23,6 +23,11 @@ class LineCollection(Shape):
     """
 
     def __init__(self, *lines: Iterable[Iterable[Number]]) -> None:
+        # check that lines that have the same starting and ending points raise an error
+        for line in lines:
+            start, end = line
+            if np.allclose(start, end):
+                raise ValueError(f'Line {line} has the same start and end point')
         self.lines = lines
         """Iterable[Iterable[numbers.Number]]: An iterable
         of two (x, y) pairs representing the endpoints of a line."""

tests/shapes/bases/test_line_collection.py

@@ -35,10 +35,10 @@ def test_distance_nonzero(self, line_collection, point, expected_distance):
         assert pytest.approx(line_collection.distance(*point)) == expected_distance
 
     @pytest.mark.parametrize('line', [[(0, 0), (0, 0)], [(-1, -1), (-1, -1)]], ids=str)
-    def test_distance_to_small_line_magnitude(self, line_collection, line):
-        """Test _distance_point_to_line() for small line magnitudes."""
-        distance = line_collection._distance_point_to_line((30, 50), line)
-        assert distance == 9999
+    def test_line_as_point(self, line):
+        """Test LineCollection raises a ValueError for small line magnitudes."""
+        with pytest.raises(ValueError):
+            LineCollection(line)
 
     def test_repr(self, line_collection):
         """Test that the __repr__() method is working."""