Add function for toggling status bits

We'll need this for toggling the `command received` bit for most
plc commands.

schunk_egu_egk_gripper_dummy/src/dummy.py

@@ -19,6 +19,8 @@ def __init__(self):
         self.plc_output = "0x0048"
         self.error_byte = 12
         self.diagnostics_byte = 15
+        self.valid_status_bits = list(range(0, 10)) + [11, 12, 13, 14, 16, 17, 31]
+        self.valid_control_bits = list(range(0, 10)) + [11, 12, 13, 14, 16, 30, 31]
         self.reserved_status_bits = [10, 15] + list(range(18, 31))
         self.reserved_control_bits = [10, 15] + list(range(17, 30))
         self.actual_position = "0x0230"
@@ -144,6 +146,15 @@ def get_status_bit(self, bit: int) -> int | bool:
         byte_index, bit_index = divmod(bit, 8)
         return 1 if self.plc_input_buffer[byte_index] & (1 << bit_index) != 0 else 0
 
+    def toggle_status_bit(self, bit: int) -> bool:
+        if bit < 0 or bit > 31:
+            return False
+        if bit in self.reserved_status_bits:
+            return False
+        byte_index, bit_index = divmod(bit, 8)
+        self.plc_input_buffer[byte_index] ^= 1 << bit_index
+        return True
+
     def set_status_error(self, error: str) -> bool:
         try:
             self.plc_input_buffer[self.error_byte] = int(error, 16)

schunk_egu_egk_gripper_dummy/tests/test_plc_communication.py

@@ -33,8 +33,7 @@ def test_dummy_rejects_reading_reserved_status_bits():
 
 def test_dummy_supports_reading_and_writing_bits_in_plc_status():
     dummy = Dummy()
-    valid_bits = list(range(0, 10)) + [11, 12, 13, 14, 16, 17, 31]
-    for bit in valid_bits:
+    for bit in dummy.valid_status_bits:
         dummy.set_status_bit(bit=bit, value=True)
         result = dummy.get_status_bit(bit=bit)
         assert isinstance(result, int)  # successful calls get the bit's value
@@ -44,8 +43,7 @@ def test_dummy_supports_reading_and_writing_bits_in_plc_status():
 def test_dummy_only_touches_specified_status_bits():
     dummy = Dummy()
     before = dummy.get_plc_input()
-    valid_bits = list(range(0, 10)) + [11, 12, 13, 14, 16, 17, 31]
-    for bit in valid_bits:
+    for bit in dummy.valid_status_bits:
         initial_value = dummy.get_status_bit(bit=bit)
         dummy.set_status_bit(bit=bit, value=True)
         dummy.set_status_bit(bit=bit, value=initial_value)
@@ -85,8 +83,7 @@ def test_dummy_rejects_writing_invalid_status_diagnostics():
 
 def test_dummy_supports_reading_bits_in_plc_control():
     dummy = Dummy()
-    valid_bits = list(range(0, 10)) + [11, 12, 13, 14, 16, 30, 31]
-    for bit in valid_bits:
+    for bit in dummy.valid_control_bits:
         result = dummy.get_control_bit(bit=bit)
         assert isinstance(result, int)  # successful calls get the bit's value
 
@@ -98,6 +95,23 @@ def test_dummy_rejects_reading_reserved_control_bits():
         assert not dummy.get_control_bit(bit)
 
 
+def test_dummy_supports_toggling_status_bits():
+    dummy = Dummy()
+    for bit in dummy.valid_status_bits:
+        before = dummy.get_status_bit(bit)
+        dummy.toggle_status_bit(bit=bit)
+        after = dummy.get_status_bit(bit)
+        assert after != before
+        dummy.toggle_status_bit(bit=bit)
+        assert dummy.get_status_bit(bit=bit) == before
+
+
+def test_dummy_rejects_toggling_reserved_status_bits():
+    dummy = Dummy()
+    for bit in dummy.reserved_status_bits:
+        assert not dummy.toggle_status_bit(bit)
+
+
 def test_dummy_supports_reading_target_position():
     dummy = Dummy()
     target_pos = 0.0123