Tape.head goes at the end! (#130)

Signed-off-by: Michel Hidalgo <[email protected]>

bdai_ros2_wrappers/bdai_ros2_wrappers/utilities.py

@@ -232,7 +232,7 @@ def head(self) -> Optional[T]:
                 return None
             if len(self._content) == 0:
                 return None
-            return self._content[0]
+            return self._content[-1]
 
     @overload
     def content(

bdai_ros2_wrappers/test/test_utilities.py

@@ -9,6 +9,15 @@
 from bdai_ros2_wrappers.utilities import Tape, either_or, ensure, namespace_with
 
 
+def test_tape_head() -> None:
+    tape: Tape[int] = Tape()
+    assert tape.head is None
+    expected_sequence = list(range(10))
+    for i in expected_sequence:
+        tape.write(i)
+        assert tape.head == i
+
+
 def test_tape_content_iteration() -> None:
     tape: Tape[int] = Tape()
     expected_sequence = list(range(10))