tck support insert NULL (#793)

small change

Co-authored-by: Yee <2520865+yixinglu@users.noreply.github.com>

tests/common/csv_import.py

@@ -111,6 +111,8 @@ class CSVImporter:
         return f'{self._insert_stmt} {src_vid}->{dst_vid}@{rank}:({",".join(props)});'
 
     def value(self, ptype: str, col):
+        if col == "__NULL__" or col == "NULL" or col == "null" or col == "Null":
+            return "NULL"
         return f'"{col}"' if ptype == 'string' else f'{col}'
 
     def vid_str(self, vid: VID, col: str):

tests/data/nba/player.csv

@@ -51,3 +51,7 @@ Grant Hill,Grant Hill,46
 Shaquile O'Neal,Shaquile O'Neal,47
 JaVale McGee,JaVale McGee,31
 Dwight Howard,Dwight Howard,33
+Null1,null,-1
+Null2,Null,-2
+Null3,NULL,-3
+Null4,__NULL__,-4

tests/tck/features/match/Base.feature

@@ -15,6 +15,16 @@ Feature: Basic match
     Then the result should be, in any order, with relax comparison:
       | v            |
       | ("Yao Ming") |
+    When executing query:
+      """
+      MATCH (v:player) WHERE v.age < 0 RETURN v
+      """
+    Then the result should be, in any order, with relax comparison:
+      | v                                      |
+      | ("Null1" :player{age: -1, name: NULL}) |
+      | ("Null2" :player{age: -2, name: NULL}) |
+      | ("Null3" :player{age: -3, name: NULL}) |
+      | ("Null4" :player{age: -4, name: NULL}) |
     When executing query:
       """
       MATCH (v:player) WHERE v.name == "Yao Ming" RETURN v.age AS Age