Use fastapi's background task mechanism for gripper motion

This seems the cleanest approach for now for giving immediate results to
post requests and having the motion run in the background.
Also adapt the unit tests accordingly.

schunk_egu_egk_gripper_dummy/schunk_egu_egk_gripper_dummy/main.py

@@ -1,8 +1,9 @@
 from src.dummy import Dummy
 
-from fastapi import FastAPI, Request, Form
+from fastapi import FastAPI, Request, Form, BackgroundTasks
 from fastapi.middleware.cors import CORSMiddleware
 from typing import Optional
+import string
 
 # Components
 dummy = Dummy()
@@ -25,9 +26,16 @@ async def post(
     value: str = Form(...),
     elem: Optional[int] = Form(None),
     callback: Optional[str] = Form(None),
+    background_tasks: BackgroundTasks = None,
 ):
     msg = {"inst": inst, "value": value, "elem": elem, "callback": callback}
-    return dummy.post(msg)
+
+    if msg["inst"] not in dummy.data:
+        return {"result": 1}
+    if not all(digit in string.hexdigits for digit in str(msg["value"])):
+        return {"result": 1}
+    background_tasks.add_task(dummy.post, msg)
+    return {"result": 0}
 
 
 @server.get("/adi/{path}")

schunk_egu_egk_gripper_dummy/src/dummy.py

@@ -3,7 +3,6 @@
 import os
 from pathlib import Path
 import json
-import string
 import struct
 
 
@@ -17,14 +16,14 @@ def __init__(self):
         self.data = None
         self.plc_input = "0x0040"
         self.plc_output = "0x0048"
+        self.actual_position = "0x0230"
+        self.actual_speed = "0x0238"
         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"
-        self.actual_speed = "0x0238"
 
         enum_config = os.path.join(
             Path(__file__).resolve().parents[1], "config/enum.json"
@@ -62,13 +61,6 @@ def _run(self) -> None:
         print("Done")
 
     def post(self, msg: dict) -> dict:
-        if "inst" not in msg and "value" not in msg:
-            return {"result": 1}
-        if msg["inst"] not in self.data:
-            return {"result": 1}
-        if not all(digit in string.hexdigits for digit in msg["value"]):
-            return {"result": 1}
-
         if msg["inst"] == self.plc_output:
             self.plc_output_buffer = bytearray(bytes.fromhex(msg["value"]))
         else:

schunk_egu_egk_gripper_dummy/tests/test_plc_communication.py

@@ -128,19 +128,17 @@ def test_dummy_supports_reading_target_speed():
 
 def test_dummy_supports_writing_actual_position():
     dummy = Dummy()
-    inst = "0x0230"  # <actual_pos>
     pos = 0.123
     dummy.set_actual_position(pos)
-    read_pos = dummy.data[inst][0]
+    read_pos = dummy.data[dummy.actual_position][0]
     read_pos = struct.unpack("f", bytes.fromhex(read_pos))[0]
     assert pytest.approx(read_pos) == pos
 
 
 def test_dummy_supports_writing_actual_speed():
     dummy = Dummy()
-    inst = "0x0238"  # <actual_vel>
     speed = 66.5
     dummy.set_actual_speed(speed)
-    read_speed = dummy.data[inst][0]
+    read_speed = dummy.data[dummy.actual_speed][0]
     read_speed = struct.unpack("f", bytes.fromhex(read_speed))[0]
     assert pytest.approx(read_speed) == speed

schunk_egu_egk_gripper_dummy/tests/test_requests.py

@@ -1,4 +1,6 @@
 from src.dummy import Dummy
+from schunk_egu_egk_gripper_dummy.main import server
+from fastapi.testclient import TestClient
 
 
 def test_dummy_responds_correctly_to_info_requests():
@@ -80,18 +82,19 @@ def test_dummy_stores_post_requests():
 
 
 def test_dummy_rejects_invalid_post_requests():
-    dummy = Dummy()
+    client = TestClient(server)
+
     valid_data = "AABBCCDD"
     valid_inst = "0x0238"
     data = {"inst": valid_inst, "value": valid_data}
-    assert dummy.post(data) == {"result": 0}
+    assert client.post("/adi/update.json", data=data).json() == {"result": 0}
 
     invalid_data = "hello:)"
     valid_inst = "0x0238"
     data = {"inst": valid_inst, "value": invalid_data}
-    assert dummy.post(data) == {"result": 1}
+    assert client.post("/adi/update.json", data=data).json() == {"result": 1}
 
     valid_data = "AABBCCDD"
     invalid_inst = "0x9999"
     data = {"inst": invalid_inst, "value": valid_data}
-    assert dummy.post(data) == {"result": 1}
+    assert client.post("/adi/update.json", data=data).json() == {"result": 1}