Add validation test for CurrentTimestamp

Author: Mariam-Almesfer

backends-velox/src/test/scala/org/apache/gluten/functions/ScalarFunctionsValidateSuite.scala

@@ -1521,4 +1521,22 @@ abstract class ScalarFunctionsValidateSuite extends FunctionsValidateSuite {
         }
     }
   }
+
+  test("current_timestamp") {
+    withSQLConf("spark.sql.optimizer.excludedRules" -> "") {
+      val df = spark.sql("SELECT current_timestamp()")
+
+      val optimizedPlan = df.queryExecution.optimizedPlan.toString()
+      assert(
+        optimizedPlan.contains("Project") && !optimizedPlan.contains("CurrentTimestamp"),
+        s"Expected CurrentTimestamp to be folded to a literal, but got: $optimizedPlan"
+      )
+
+      checkFallbackOperators(df, 1)
+
+      val result = df.collect()
+      assert(result.length == 1, "Expected exactly one row")
+      assert(result(0).getTimestamp(0) != null, "Expected a non-null timestamp")
+    }
+  }
 }

docs/get-started/VeloxABFS.md

@@ -8,15 +8,41 @@ ABFS is an important data store for big data users. This doc discusses config de
 
 # Working with ABFS
 
-## Configuring ABFS Access Token
+## Configuring ABFS Authentication Type
 
-To configure access to your storage account, replace <storage-account> with the name of your account. This property aligns with Spark configurations. By setting this config multiple times using different storage account names, you can access multiple ABFS accounts.
+The authentication mechanism for an Azure storage account is controlled by the following property. Replace `<storage-account>` with the name of your Azure Storage account. Defaults to `SharedKey` if not set.
+
+```sh
+spark.hadoop.fs.azure.account.auth.type.<storage-account>.dfs.core.windows.net  SharedKey
+```
+
+Allowed values are `SharedKey`, `OAuth`, and `SAS`.
+
+## Configuring ABFS Access Key
+
+To configure access to your storage account using a shared key, replace `<storage-account>` with the name of your account. This property aligns with Spark configurations. By setting this config multiple times using different storage account names, you can access multiple ABFS accounts.
 
 ```sh
 spark.hadoop.fs.azure.account.key.<storage-account>.dfs.core.windows.net  XXXXXXXXX
 ```
 
-### Other authentatication methods are not yet supported.
+## Configuring ABFS SAS Token
+
+To authenticate using a pre-generated SAS (Shared Access Signature) token, set the following property. This token provides scoped and time-limited access to specific resources.
+
+```sh
+spark.hadoop.fs.azure.sas.fixed.token.<storage-account>.dfs.core.windows.net  XXXXXXXXX
+```
+
+## Configuring ABFS OAuth
+
+To authenticate using OAuth 2.0, set the following properties. Replace `<storage-account>` with the name of your Azure Storage account and `<tenant-id>` with your Azure AD tenant ID.
+
+```sh
+spark.hadoop.fs.azure.account.oauth2.client.id.<storage-account>.dfs.core.windows.net      XXXXXXXXX
+spark.hadoop.fs.azure.account.oauth2.client.secret.<storage-account>.dfs.core.windows.net  XXXXXXXXX
+spark.hadoop.fs.azure.account.oauth2.client.endpoint.<storage-account>.dfs.core.windows.net  https://login.microsoftonline.com/<tenant-id>/oauth2/token
+```
 
 # Local Caching support