MWLServer now supports C-ECHO (#122)

`MWLServer`: registers a C-ECHO handler and adds `Verification` to its supported presentation contexts.

`PACSServer`: adds `Verification` to its supported presentation contexts. A C-ECHO handler was already registered, but without the Verification context the association would be rejected before reaching it. pynetdicom's [Verification Service Examples](https://pydicom.github.io/pynetdicom/stable/examples/verification.html) shows that an SCP must explicitly call `ae.add_supported_context(Verification)`.

Author: carlosmartinez

src/server.py

@@ -14,6 +14,7 @@
     DigitalMammographyXRayImageStorageForProcessing,  # type: ignore[attr-defined]
     ModalityPerformedProcedureStep,  # type: ignore[attr-defined]
     ModalityWorklistInformationFind,  # type: ignore[attr-defined]
+    Verification,  # type: ignore[attr-defined]
 )
 
 from services.dicom.c_echo import CEcho
@@ -68,6 +69,7 @@ def start(self):
             dicom_uid.JPEG2000Lossless,
         ]
         self.ae = AE(ae_title=self.ae_title)
+        self.ae.add_supported_context(Verification)
         self.ae.add_supported_context(DigitalMammographyXRayImageStorageForPresentation, transfer_syntaxes)
         self.ae.add_supported_context(DigitalMammographyXRayImageStorageForProcessing, transfer_syntaxes)
 
@@ -120,10 +122,12 @@ def start(self):
         logger.info(f"Starting MWL server: {self.ae_title} on port {self.port}")
 
         self.ae = AE(ae_title=self.ae_title)
+        self.ae.add_supported_context(Verification)
         self.ae.add_supported_context(ModalityWorklistInformationFind)
         self.ae.add_supported_context(ModalityPerformedProcedureStep)
 
         handlers = [
+            (evt.EVT_C_ECHO, CEcho().call),
             (evt.EVT_C_FIND, CFind(self.storage).call),
             (evt.EVT_N_CREATE, NCreate(self.storage).call),
             (evt.EVT_N_SET, NSet(self.storage).call),

tests/test_server.py

@@ -7,6 +7,7 @@
     DigitalMammographyXRayImageStorageForProcessing,
     ModalityPerformedProcedureStep,
     ModalityWorklistInformationFind,
+    Verification,
 )
 
 from server import MWLServer, PACSServer
@@ -54,6 +55,7 @@ def test_start(self, mock_c_store, mock_c_echo, mock_ae, _mock_pacs_storage, _mo
 
         mock_ae.assert_called_once_with(ae_title="SCREENING_PACS")
         add_context_calls = [call.args[0] for call in mock_ae.return_value.add_supported_context.call_args_list]
+        assert Verification in add_context_calls
         assert DigitalMammographyXRayImageStorageForPresentation in add_context_calls
         assert DigitalMammographyXRayImageStorageForProcessing in add_context_calls
         mock_ae.return_value.start_server.assert_called_once_with(
@@ -100,7 +102,8 @@ def test_init_defaults(self, mock_storage):
         mock_storage.assert_called_once_with("/var/lib/pacs/worklist.db")
 
     @patch(f"{MWLServer.__module__}.AE")
-    def test_start(self, mock_ae, _):
+    @patch(f"{MWLServer.__module__}.CEcho")
+    def test_start(self, mock_c_echo, mock_ae, _):
         subject = MWLServer()
         mock_ae_instance = MagicMock()
         mock_ae.return_value = mock_ae_instance
@@ -110,6 +113,7 @@ def test_start(self, mock_ae, _):
         assert subject.ae == mock_ae_instance
 
         mock_ae.assert_called_once_with(ae_title="MWL_SCP")
+        mock_ae_instance.add_supported_context.assert_any_call(Verification)
         mock_ae_instance.add_supported_context.assert_any_call(
             ModalityWorklistInformationFind,
         )
@@ -121,7 +125,8 @@ def test_start(self, mock_ae, _):
         assert args[0] == ("0.0.0.0", 4243)
         assert kwargs["block"] is True
         assert "evt_handlers" in kwargs
-        assert len(kwargs["evt_handlers"]) == 3
+        assert (evt.EVT_C_ECHO, mock_c_echo.return_value.call) in kwargs["evt_handlers"]
+        assert len(kwargs["evt_handlers"]) == 4
 
     @patch(f"{MWLServer.__module__}.AE")
     def test_stop(self, *_):