fix unit test

Author: Jiayu Liu

datafusion/tests/sql.rs

@@ -2906,13 +2906,15 @@ async fn test_current_timestamp_expressions_non_optimized() -> Result<()> {
     let t2 = t2_naive.timestamp();
     assert!(t1 <= t2 && t2 <= t3);
     assert_eq!(res2, res1);
+
+    Ok(())
 }
 
 #[tokio::test]
 async fn test_random_expression() -> Result<()> {
     let mut ctx = create_ctx()?;
-    let sql = format!("SELECT random() r1");
-    let actual = execute(&mut ctx, sql.as_str()).await;
+    let sql = "SELECT random() r1";
+    let actual = execute(&mut ctx, sql).await;
     let r1 = actual[0][0].parse::<f64>().unwrap();
     assert!(0.0 <= r1);
     assert!(r1 < 1.0);