More Color Fixes (#243)

* More color fixes.

* Added assert.

src/scenic/core/object_types.py

@@ -497,9 +497,7 @@ def _specify(cls, context, prop, value):
                     "Color property contains value not between 0 and 1 (inclusive)."
                 )
 
-            if len(value) == 3:
-                value = (value[0], value[1], value[2], 1)
-            elif len(value) != 4:
+            if not 3 <= len(value) <= 4:
                 raise ValueError(f"Color property has incorrect length {len(value)}.")
 
         object.__setattr__(context, prop, value)
@@ -1557,7 +1555,14 @@ def show3D(self, viewer, highlight=False):
         if highlight:
             object_mesh.visual.face_colors = [30, 179, 0, 255]
         elif self.color is not None:
-            r, g, b, a = self.color
+            if len(self.color) == 3:
+                r, g, b = self.color
+                a = 1
+            elif len(self.color) == 4:
+                r, g, b, a = self.color
+            else:
+                assert False
+
             object_mesh.visual.face_colors = [255 * r, 255 * g, 255 * b, 255 * a]
 
         viewer.add_geometry(object_mesh)

tests/simulators/utils/test_colors.py

@@ -1,6 +1,16 @@
 import pytest
 
-from scenic.simulators.utils.colors import NoisyColorDistribution
+from scenic.simulators.utils.colors import Color, NoisyColorDistribution
+from tests.utils import sampleEgoFrom
+
+
+def test_color_class():
+    program = """
+        from scenic.simulators.utils.colors import Color
+        ego = new Object with color Color.defaultCarColor()
+        """
+    ego = sampleEgoFrom(program)
+    assert isinstance(ego.color, Color)
 
 
 def test_add_noise():

tests/syntax/test_specifiers.py

@@ -1180,7 +1180,7 @@ def test_color():
         ego = new Object with color (0.5,0.5,0.5)
         """
     ego = sampleEgoFrom(program)
-    assert ego.color == (0.5, 0.5, 0.5, 1)
+    assert ego.color == (0.5, 0.5, 0.5)
 
     with pytest.raises(ValueError):
         program = """