fix: get_absolute_location includes anchor even if parent is None

Author: rickwierenga

CHANGELOG.md

@@ -129,6 +129,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/).
 - fix get_child_location for resources rotated by 180 degrees (https://github.com/PyLabRobot/pylabrobot/pull/269)
 - volume tracking on channel 1-n (https://github.com/PyLabRobot/pylabrobot/pull/273)
 - correct trash location on Vantage (https://github.com/PyLabRobot/pylabrobot/pull/285)
+- `Resource.get_absolute_location` includes anchor even if parent is None
 
 ### Removed
 

pylabrobot/resources/resource.py

@@ -212,22 +212,24 @@ def get_absolute_location(self, x: str = "l", y: str = "f", z: str = "b") -> Coo
     """
 
     assert self.location is not None, f"Resource {self.name} has no location."
+
+    rotated_anchor = Coordinate(
+      *matrix_vector_multiply_3x3(
+        self.get_absolute_rotation().get_rotation_matrix(),
+        self.get_anchor(x=x, y=y, z=z).vector(),
+      )
+    )
+
     if self.parent is None:
-      return self.location
-    parent_pos = self.parent.get_absolute_location()
+      return self.location + rotated_anchor
 
+    parent_pos = self.parent.get_absolute_location()
     rotated_location = Coordinate(
       *matrix_vector_multiply_3x3(
         self.parent.get_absolute_rotation().get_rotation_matrix(),
         self.location.vector(),
       )
     )
-    rotated_anchor = Coordinate(
-      *matrix_vector_multiply_3x3(
-        self.get_absolute_rotation().get_rotation_matrix(),
-        self.get_anchor(x=x, y=y, z=z).vector(),
-      )
-    )
     return parent_pos + rotated_location + rotated_anchor
 
   def _get_rotated_corners(self) -> List[Coordinate]:

pylabrobot/resources/resource_tests.py

@@ -1,5 +1,3 @@
-"""Tests for Resource"""
-
 import math
 import unittest
 import unittest.mock
@@ -138,6 +136,13 @@ def test_get_absolute_location_with_anchor(self):
       Coordinate(20, 15, 20),
     )
 
+    single = Resource("single", size_x=5, size_y=5, size_z=5)
+    single.location = Coordinate.zero()
+    self.assertEqual(
+      single.get_absolute_location(x="right", y="front", z="top"),
+      Coordinate(5, 0, 5),
+    )
+
   def test_unassign_child(self):
     deck = Deck()
     parent = Resource("parent", size_x=10, size_y=10, size_z=10)