Enable CI for robot devices with mocked versions (#398)

Co-authored-by: Simon Alibert <75076266+aliberts@users.noreply.github.com>

tests/mock_dynamixel_sdk.py

@@ -0,0 +1,87 @@
+"""Mocked classes and functions from dynamixel_sdk to allow for continuous integration
+and testing code logic that requires hardware and devices (e.g. robot arms, cameras)
+
+Warning: These mocked versions are minimalist. They do not exactly mock every behaviors
+from the original classes and functions (e.g. return types might be None instead of boolean).
+"""
+
+# from dynamixel_sdk import COMM_SUCCESS
+
+DEFAULT_BAUDRATE = 9_600
+COMM_SUCCESS = 0  # tx or rx packet communication success
+
+
+def convert_to_bytes(value, bytes):
+    # TODO(rcadene): remove need to mock `convert_to_bytes` by implemented the inverse transform
+    # `convert_bytes_to_value`
+    del bytes  # unused
+    return value
+
+
+class PortHandler:
+    def __init__(self, port):
+        self.port = port
+        # factory default baudrate
+        self.baudrate = DEFAULT_BAUDRATE
+
+    def openPort(self):  # noqa: N802
+        return True
+
+    def closePort(self):  # noqa: N802
+        pass
+
+    def setPacketTimeoutMillis(self, timeout_ms):  # noqa: N802
+        del timeout_ms  # unused
+
+    def getBaudRate(self):  # noqa: N802
+        return self.baudrate
+
+    def setBaudRate(self, baudrate):  # noqa: N802
+        self.baudrate = baudrate
+
+
+class PacketHandler:
+    def __init__(self, protocol_version):
+        del protocol_version  # unused
+        # Use packet_handler.data to communicate across Read and Write
+        self.data = {}
+
+
+class GroupSyncRead:
+    def __init__(self, port_handler, packet_handler, address, bytes):
+        self.packet_handler = packet_handler
+
+    def addParam(self, motor_index):  # noqa: N802
+        if motor_index not in self.packet_handler.data:
+            # Initialize motor default values
+            self.packet_handler.data[motor_index] = {
+                # Key (int) are from X_SERIES_CONTROL_TABLE
+                7: motor_index,  # ID
+                8: DEFAULT_BAUDRATE,  # Baud_rate
+                10: 0,  # Drive_Mode
+                64: 0,  # Torque_Enable
+                # Set 2560 since calibration values for Aloha gripper is between start_pos=2499 and end_pos=3144
+                # For other joints, 2560 will be autocorrected to be in calibration range
+                132: 2560,  # Present_Position
+            }
+
+    def txRxPacket(self):  # noqa: N802
+        return COMM_SUCCESS
+
+    def getData(self, index, address, bytes):  # noqa: N802
+        return self.packet_handler.data[index][address]
+
+
+class GroupSyncWrite:
+    def __init__(self, port_handler, packet_handler, address, bytes):
+        self.packet_handler = packet_handler
+        self.address = address
+
+    def addParam(self, index, data):  # noqa: N802
+        self.changeParam(index, data)
+
+    def txPacket(self):  # noqa: N802
+        return COMM_SUCCESS
+
+    def changeParam(self, index, data):  # noqa: N802
+        self.packet_handler.data[index][self.address] = data