Added stage tests and tidied up rescue

openflexure_microscope/rescue/check_sangaboard.py

@@ -0,0 +1,44 @@
+from .error_sources import ErrorSource, WarningSource
+
+from openflexure_microscope.config import user_configuration
+
+
+def main():
+    error_sources = []
+
+    try:
+        from sangaboard import Sangaboard
+    except Exception as e:  # pylint: disable=W0703
+        error_sources.append(ErrorSource(
+            "Sangaboard module could not be imported."
+        ))
+    else:
+        configuration = user_configuration.load()
+        stage_type = configuration["stage"].get("type")
+        stage_port = configuration["stage"].get("port")
+
+        error_sources.append(WarningSource(
+            "Stage serial port is not specified in configuration. Application will scan ports for a Sangaboard."
+        ))
+
+
+        # If any Sangaboard-based stage is configured for use
+        if stage_type in ("SangaBoard", "SangaStage", "SangaDeltaStage"):
+            # Try connecting on the specified port
+            try:
+                _ = Sangaboard(stage_port)
+            except FileNotFoundError as e:  # pylint: disable=W0703
+                if stage_port:
+                    error_sources.append(ErrorSource(
+                        f"No {stage_type} device was found on the configured port {stage_port}."
+                    ))
+                else:
+                    error_sources.append(ErrorSource(
+                        f"No {stage_type} device was found during port scanning."
+                    ))
+        else:
+            error_sources.append(ErrorSource(
+                f"Invalid stage type {stage_type} specified in configuration file."
+            ))
+
+    return error_sources