follow-up to #3491, made errors more consistent. fixes #3527

Author: behackl

manim/animation/animation.py

@@ -193,7 +193,8 @@ def begin(self) -> None:
         """
         if self.run_time <= 0:
             raise ValueError(
-                f"{self} has a runtime of <= 0 seconds, which cannot be rendered correctly! please set a runtime > 0"
+                f"{self} has a run_time of <= 0 seconds, this cannot be rendered correctly. "
+                "Please set the run_time to be positive"
             )
         self.starting_mobject = self.create_starting_mobject()
         if self.suspend_mobject_updating:

manim/animation/composition.py

@@ -86,12 +86,13 @@ def get_all_mobjects(self) -> Sequence[Mobject]:
     def begin(self) -> None:
         if self.run_time <= 0:
             tmp = (
-                "please set a runtime > 0"
+                "Please set the run_time to be positive"
                 if len(self.animations) != 0
-                else "Please add at least one Animation"
+                else "Please add at least one Animation with positive run_time"
             )
             raise ValueError(
-                f"{self} has a runtime of 0 seconds. Which cannot be rendered correctly! {tmp}."
+                f"{self} has a run_time of 0 seconds, this cannot be "
+                f"rendered correctly. {tmp}."
             )
         if self.suspend_mobject_updating:
             self.group.suspend_updating()

tests/module/animation/test_composition.py

@@ -172,10 +172,10 @@ def test_animationgroup_is_passing_remover_to_nested_animationgroups():
 
 
 def test_empty_animation_group_fails():
-    with pytest.raises(ValueError):
+    with pytest.raises(ValueError, match="Please add at least one Animation"):
         AnimationGroup().begin()
 
 
 def test_empty_animation_fails():
-    with pytest.raises(ValueError):
+    with pytest.raises(ValueError, match="Please set the run_time to be positive"):
         FadeIn(None, run_time=0).begin()