Update diagnostics/os_diagnostics.py

diagnostics/os_diagnostics.py

@@ -1,6 +1,7 @@
 from pybricks.parameters import Port
 from uerrno import EAGAIN, EBUSY, ECANCELED, EINVAL, EIO, ENODEV, EOPNOTSUPP, EPERM, ETIMEDOUT
 import uio
+import ujson
 from pybricks.iodevices import UARTDevice as _UARTDevice
 from pybricks.tools import wait, multitask, run_task
 
@@ -65,6 +66,11 @@ class OSDiagnostics:
         uiotestobject.print_results()
         self.successfultests += uiotestobject.successfultests
         self.failedtests.update(uiotestobject.failedtests)
+    def testUJSON(self):
+        ujsontestobject = UJSONTest(self.hub, self.motorclass)
+        ujsontestobject.print_results()
+        self.successfultests += ujsontestobject.successfultests
+        self.failedtests.update(ujsontestobject.failedtests)
 
     
 
@@ -336,3 +342,80 @@ class UIOTest(OSDiagnostics):
             print("Failed tests:")
             for key, value in self.failedtests.items():
                 print(f"  {key}: {value}")
+class UJSONTest:
+    def __init__(self, hub, motorclass):
+        self.hub = hub
+        self.motorclass = motorclass
+        self.successfultests = 0
+        self.failedtests = {}
+
+    # Tests ujson.dumps() and ujson.loads()
+    def testdumpsloads(self):
+        try:
+            original = {"robot": "Pybricks", "speed": 500, "active": True}
+
+            json_str = ujson.dumps(original)
+            print(f"Serialized (via dumps()): {json_str}")
+
+            restored = ujson.loads(json_str)
+            print(f"Deserialized (via loads()): {restored}")
+
+            # TODO: After confirming dumps/loads works on this system, add equality tests
+
+            print("Completed Test 1/3: dumps/loads - SUCCESSFUL")
+            self.successfultests += 1
+        except Exception as ex:
+            print("An unexpected error occurred.")
+            print("Completed Test 1/3: dumps/loads - FAILED")
+            self.failedtests["dumps/loads"] = getattr(ex, "errno", str(ex))
+
+    # Tests ujson.loads() raising ValueError on malformed input
+    def testloadsinvalid(self):
+        try:
+            ujson.loads("{not valid json}")
+            print("No error raised.")
+            print("Completed Test 2/3: loads invalid - FAILED")
+            self.failedtests["loads_invalid"] = "No error raised"
+        except ValueError:
+            print("ValueError raised on malformed JSON, as expected.")
+            print("Completed Test 2/3: loads invalid - SUCCESSFUL")
+            self.successfultests += 1
+        except Exception as ex:
+            print("An unexpected error occurred.")
+            print("Completed Test 2/3: loads invalid - FAILED")
+            self.failedtests["loads_invalid"] = getattr(ex, "errno", str(ex))
+
+    # Tests ujson.dump() and ujson.load() using a uio.StringIO stream
+    def testdumpload(self):
+        try:
+            original = {"hub": "SPIKE Prime", "port": "A", "value": 42}
+
+            stream = uio.StringIO()
+            ujson.dump(original, stream)
+            print(f"Serialized to stream (via dump()): {stream.getvalue()}")
+
+            stream.seek(0)
+            restored = ujson.load(stream)
+            print(f"Deserialized from stream (via load()): {restored}")
+
+            stream.close()
+
+            # TODO: After confirming dump/load works on this system, add
+            # equality assertions to verify round-trip fidelity.
+
+            print("Completed Test 3/3: dump/load (stream) - SUCCESSFUL")
+            self.successfultests += 1
+        except Exception as ex:
+            print("An unexpected error occurred.")
+            print("Completed Test 3/3: dump/load (stream) - FAILED")
+            self.failedtests["dump/load"] = getattr(ex, "errno", str(ex))
+
+    def print_results(self):
+        self.testdumpsloads()
+        self.testloadsinvalid()
+        self.testdumpload()
+        print(f"\n=== Results: {self.successfultests}/3 tests passed ===")
+        if self.failedtests:
+            print("Failed tests:")
+            for key, value in self.failedtests.items():
+                print(f"  {key}: {value}")