fix - corrections for setting stroke related attributes on VMobject (#1051)

Author: ksachdeva

manim/mobject/types/vectorized_mobject.py

@@ -186,14 +186,20 @@ def set_stroke(
         if background:
             array_name = "background_stroke_rgbas"
             width_name = "background_stroke_width"
+            opacity_name = "background_stroke_opacity"
+            color_name = "background_stroke_color"
         else:
             array_name = "stroke_rgbas"
             width_name = "stroke_width"
+            opacity_name = "stroke_opacity"
+            color_name = "stroke_color"
         self.update_rgbas_array(array_name, color, opacity)
         if width is not None:
             setattr(self, width_name, width)
         if opacity is not None:
-            self.stroke_opacity = opacity
+            setattr(self, opacity_name, opacity)
+        if color is not None:
+            setattr(self, color_name, color)
         return self
 
     def set_background_stroke(self, **kwargs):

tests/test_stroke.py

@@ -0,0 +1,24 @@
+from manim import VMobject
+import manim.utils.color as C
+
+
+def test_stroke_props_in_ctor():
+    m = VMobject(stroke_color=C.ORANGE, stroke_width=10)
+    assert m.stroke_color == C.ORANGE
+    assert m.stroke_width == 10
+
+
+def test_set_stroke():
+    m = VMobject()
+    m.set_stroke(color=C.ORANGE, width=2, opacity=0.8)
+    assert m.stroke_width == 2
+    assert m.stroke_opacity == 0.8
+    assert m.stroke_color == C.ORANGE
+
+
+def test_set_background_stroke():
+    m = VMobject()
+    m.set_stroke(color=C.ORANGE, width=2, opacity=0.8, background=True)
+    assert m.background_stroke_width == 2
+    assert m.background_stroke_opacity == 0.8
+    assert m.background_stroke_color == C.ORANGE