Fix edge case for code actions

Resolves #96

jedi_language_server/text_edit_utils.py

@@ -162,13 +162,20 @@ def get_opcode_position_lookup(
     structure within which one can look up opcode-friendly values. It
     relies on the `RangeDict` above, which lets you look up a value
     within a range of linear values
+
+    Range contains padding at the start and the end to accommodate edge cases
+    within editors.
     """
     original_lines = code.splitlines(keepends=True)
     line_lookup = RangeDict()
+    last_line_number = len(original_lines) - 1
     start = 0
     for line, code_line in enumerate(original_lines):
         end = start + len(code_line)
-        key = range(start, end)
+        key = range(
+            start if line != 0 else start - 1,
+            end if line != last_line_number else end + 1,
+        )
         line_lookup[key] = LinePosition(start, end, line, code_line)
         start = end
     return line_lookup

tests/lsp_tests/test_refactoring.py

@@ -238,3 +238,54 @@ def test_lsp_code_action() -> None:
         actual[1]["edit"]["documentChanges"][0]["edits"] = []
 
         assert_that(actual, is_(expected))
+
+
+def test_lsp_code_action2() -> None:
+    """Tests edge case for code actions.
+
+    Identified in: https://github.com/pappasam/jedi-language-server/issues/96
+    """
+
+    with session.LspSession() as ls_session:
+        ls_session.initialize()
+        uri = as_uri((REFACTOR_TEST_ROOT / "code_action_test2.py"))
+        actual = ls_session.text_document_code_action(
+            {
+                "textDocument": {"uri": uri},
+                "range": {
+                    "start": {"line": 2, "character": 6},
+                    "end": {"line": 2, "character": 6},
+                },
+                "context": {"diagnostics": []},
+            }
+        )
+
+        expected = [
+            {
+                "title": StringPattern(
+                    r"Extract expression into function 'func_\w+'"
+                ),
+                "kind": "refactor.extract",
+                "edit": {
+                    "documentChanges": [
+                        {
+                            "textDocument": {
+                                "uri": uri,
+                                "version": 0,
+                            },
+                            "edits": [],
+                        }
+                    ]
+                },
+            },
+        ]
+
+        # Cannot use hamcrest directly for this due to unpredictable
+        # variations in how the text edits are generated.
+
+        assert_that(len(actual), is_(len(expected)))
+
+        # Remove the edits
+        actual[0]["edit"]["documentChanges"][0]["edits"] = []
+
+        assert_that(actual, is_(expected))

tests/test_data/refactoring/code_action_test2.py

@@ -0,0 +1,3 @@
+import random
+
+random.gauss