reporter: Report last line and last column of code snippet (#760)

python_ta/reporters/json_reporter.py

@@ -1,9 +1,10 @@
 import json
+from typing import Dict, List
 
 from pylint.interfaces import IReporter
 from pylint.reporters.ureports.nodes import BaseLayout
 
-from .core import PythonTaReporter
+from .core import NewMessage, PythonTaReporter
 
 
 class JSONReporter(PythonTaReporter):
@@ -17,6 +18,8 @@ class JSONReporter(PythonTaReporter):
 
     OUTPUT_FILENAME = "pyta_report.json"
 
+    messages: Dict[str, List[NewMessage]]
+
     def display_messages(self, layout: BaseLayout) -> None:
         """Hook for displaying the messages of the reporter
 
@@ -30,7 +33,23 @@ def display_messages(self, layout: BaseLayout) -> None:
         output = []
         for k, msgs in self.messages.items():
             output.append(
-                {"filename": k, "msgs": [msg._replace(node=None)._asdict() for msg in msgs]}
+                {
+                    "filename": k,
+                    "msgs": [
+                        {**msg._replace(node=None)._asdict(), **self._snippet_endings(msg)}
+                        for msg in msgs
+                    ],
+                }
             )
 
         self.writeln(json.dumps(output, indent=4))
+
+    def _snippet_endings(self, msg: NewMessage) -> Dict[str, int]:
+        """Return a dictionary containing the index of the last line and the index of the last column of the
+        error reported by the message in msg.
+        """
+        if msg.node is None:
+            line_end, column_end = msg.line, len(self.source_lines[msg.line - 1])
+        else:
+            line_end, column_end = msg.node.end_lineno, msg.node.end_col_offset
+        return {"line_end": line_end, "column_end": column_end}