correct default values for builtin variables

Author: d-biehl

robotcode/language_server/robotframework/diagnostics/library_doc.py

@@ -943,28 +943,28 @@ def _get_default_variables() -> Any:
             "${False}": False,
             "${None}": None,
             "${null}": None,
-            "${TEST NAME}": None,
+            "${TEST NAME}": '',
             "@{TEST TAGS}": [],
-            "${TEST DOCUMENTATION}": None,
-            "${TEST STATUS}": None,
-            "${TEST MESSAGE}": None,
-            "${PREV TEST NAME}": None,
-            "${PREV TEST STATUS}": None,
-            "${PREV TEST MESSAGE}": None,
-            "${SUITE NAME}": None,
-            "${SUITE SOURCE}": None,
-            "${SUITE DOCUMENTATION}": None,
+            "${TEST DOCUMENTATION}": '',
+            "${TEST STATUS}": '',
+            "${TEST MESSAGE}": '',
+            "${PREV TEST NAME}": '',
+            "${PREV TEST STATUS}": '',
+            "${PREV TEST MESSAGE}": '',
+            "${SUITE NAME}": '',
+            "${SUITE SOURCE}": '',
+            "${SUITE DOCUMENTATION}": '',
             "&{SUITE METADATA}": {},
-            "${SUITE STATUS}": None,
-            "${SUITE MESSAGE}": None,
-            "${KEYWORD STATUS}": None,
-            "${KEYWORD MESSAGE}": None,
-            "${LOG LEVEL}": None,
-            "${OUTPUT FILE}": None,
-            "${LOG FILE}": None,
-            "${REPORT FILE}": None,
-            "${DEBUG FILE}": None,
-            "${OUTPUT DIR}": None,
+            "${SUITE STATUS}": '',
+            "${SUITE MESSAGE}": '',
+            "${KEYWORD STATUS}": '',
+            "${KEYWORD MESSAGE}": '',
+            "${LOG LEVEL}": '',
+            "${OUTPUT FILE}": '',
+            "${LOG FILE}": '',
+            "${REPORT FILE}": '',
+            "${DEBUG FILE}": '',
+            "${OUTPUT DIR}": '',
         }.items():
             __default_variables[k] = v