[EXPERIMENTAL] Fix some graph tests

manim/mobject/graph.py

@@ -7,6 +7,7 @@
     "DiGraph",
 ]
 
+import contextlib
 import itertools as it
 from collections.abc import Hashable, Iterable, Sequence
 from copy import copy
@@ -18,7 +19,7 @@
 if TYPE_CHECKING:
     from typing import TypeAlias
 
-    from manim.scene.scene import Scene
+    from manim.animation.scene_buffer import SceneBuffer
     from manim.typing import Point3D, Point3DLike
 
     NxGraph: TypeAlias = nx.classes.graph.Graph | nx.classes.digraph.DiGraph
@@ -908,10 +909,12 @@ def _add_vertices_animation(self, *args, anim_args=None, **kwargs):
 
         vertex_mobjects = self._create_vertices(*args, **kwargs)
 
-        def on_finish(scene: Scene):
+        def on_finish(buf: SceneBuffer | None):
             for v in vertex_mobjects:
-                scene.remove(v[-1])
                 self._add_created_vertex(*v)
+                if buf is not None:
+                    with contextlib.suppress(Exception):
+                        buf.replace(v[-1])
 
         return AnimationGroup(
             *(animation(v[-1], **anim_args) for v in vertex_mobjects),
@@ -1565,6 +1568,9 @@ def update_edges(self, graph):
     def __repr__(self: Graph) -> str:
         return f"Undirected graph on {len(self.vertices)} vertices and {len(self.edges)} edges"
 
+    def __str__(self: Graph) -> str:
+        return self.__repr__()
+
 
 class DiGraph(GenericGraph):
     """A directed graph.
@@ -1782,3 +1788,6 @@ def update_edges(self, graph):
 
     def __repr__(self: DiGraph) -> str:
         return f"Directed graph on {len(self.vertices)} vertices and {len(self.edges)} edges"
+
+    def __str__(self: DiGraph) -> str:
+        return self.__repr__()

tests/module/mobject/test_graph.py

@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+import numpy as np
 import pytest
 
 from manim import DiGraph, Graph, LabeledLine, Manager, Scene, Text, tempconfig
@@ -134,9 +135,9 @@ def test_custom_graph_layout_dict():
         [1, 2, 3], [(1, 2), (2, 3)], layout={1: [0, 0, 0], 2: [1, 1, 0], 3: [1, -1, 0]}
     )
     assert str(G) == "Undirected graph on 3 vertices and 2 edges"
-    assert all(G.vertices[1].get_center() == [0, 0, 0])
-    assert all(G.vertices[2].get_center() == [1, 1, 0])
-    assert all(G.vertices[3].get_center() == [1, -1, 0])
+    np.testing.assert_allclose(G.vertices[1].get_center(), [0, 0, 0])
+    np.testing.assert_allclose(G.vertices[2].get_center(), [1, 1, 0])
+    np.testing.assert_allclose(G.vertices[3].get_center(), [1, -1, 0])
 
 
 def test_graph_layouts():
@@ -165,9 +166,9 @@ def layout_func(graph, scale):
         return {vertex: [vertex, vertex, 0] for vertex in graph}
 
     G = Graph([1, 2, 3], [(1, 2), (2, 3)], layout=layout_func)
-    assert all(G.vertices[1].get_center() == [1, 1, 0])
-    assert all(G.vertices[2].get_center() == [2, 2, 0])
-    assert all(G.vertices[3].get_center() == [3, 3, 0])
+    np.testing.assert_allclose(G.vertices[1].get_center(), [1, 1, 0])
+    np.testing.assert_allclose(G.vertices[2].get_center(), [2, 2, 0])
+    np.testing.assert_allclose(G.vertices[3].get_center(), [3, 3, 0])
 
 
 def test_custom_graph_layout_function_with_kwargs():