test(databricks): add explicit tests for SET VAR / SET VARIABLE [CLAUDE] (#7490)

SET VAR and SET VARIABLE were already supported via inheritance from
SparkParser (fixed in #7235), but had no Databricks-specific test
coverage. Adds round-trip identity tests for all main variants.

Closes #7358

Co-authored-by: Giorgos Michas <geomichas96@gmail.com>

Author: baruchoxman

tests/dialects/test_databricks.py

@@ -491,6 +491,15 @@ def test_overlay(self):
             "SELECT OVERLAY('Spark SQL' PLACING 'ANSI ' FROM 7 FOR 0)",
         )
 
+    def test_set_variable(self):
+        # Both SET VAR and SET VARIABLE are synonyms; both normalize to SET VARIABLE on output
+        self.validate_identity("SET VAR v = 5", "SET VARIABLE v = 5")
+        self.validate_identity("SET VARIABLE v = 5")
+        self.validate_identity("SET VARIABLE v1 = 1, v2 = '2'")
+        self.validate_identity("SET VARIABLE (v1, v2) = (SELECT 1, 2)")
+        self.validate_identity("SET VARIABLE v = (SELECT MAX(c1) FROM VALUES (1), (2) AS T(c1))")
+        self.validate_identity("SET VARIABLE v = DEFAULT")
+ 
     def test_iff(self):
         # IFF is a synonym for IF in Databricks; it normalizes to IF on output
         self.validate_all(