From a2e8b6189f80e723d95782b8a89fcfae797367fa Mon Sep 17 00:00:00 2001
From: Devin D'Angelo <devinjdangelo@gmail.com>
Date: Wed, 13 Mar 2024 19:20:11 -0400
Subject: [PATCH] add roundtrip tests

---
 README.md                               |  1 +
 datafusion/sql/src/unparser/expr.rs     |  4 ++--
 datafusion/sql/tests/sql_integration.rs | 17 ++++++++++-------
 3 files changed, 13 insertions(+), 9 deletions(-)

diff --git a/README.md b/README.md
index e5ac9503be44..abd727672aca 100644
--- a/README.md
+++ b/README.md
@@ -83,6 +83,7 @@ Default features:
 - `parquet`: support for reading the [Apache Parquet] format
 - `regex_expressions`: regular expression functions, such as `regexp_match`
 - `unicode_expressions`: Include unicode aware functions such as `character_length`
+- `unparser` : enables support to reverse LogicalPlans back into SQL
 
 Optional features:
 
diff --git a/datafusion/sql/src/unparser/expr.rs b/datafusion/sql/src/unparser/expr.rs
index 0edcf1a3e3ee..403a7c6193d0 100644
--- a/datafusion/sql/src/unparser/expr.rs
+++ b/datafusion/sql/src/unparser/expr.rs
@@ -461,8 +461,8 @@ impl Unparser<'_> {
             DataType::Binary => todo!(),
             DataType::FixedSizeBinary(_) => todo!(),
             DataType::LargeBinary => todo!(),
-            DataType::Utf8 => todo!(),
-            DataType::LargeUtf8 => todo!(),
+            DataType::Utf8 => Ok(ast::DataType::Varchar(None)),
+            DataType::LargeUtf8 => Ok(ast::DataType::Text),
             DataType::List(_) => todo!(),
             DataType::FixedSizeList(_, _) => todo!(),
             DataType::LargeList(_) => todo!(),
diff --git a/datafusion/sql/tests/sql_integration.rs b/datafusion/sql/tests/sql_integration.rs
index fdf7ab8c3d28..396eebfdd767 100644
--- a/datafusion/sql/tests/sql_integration.rs
+++ b/datafusion/sql/tests/sql_integration.rs
@@ -4493,8 +4493,11 @@ impl TableSource for EmptyTable {
 #[test]
 fn roundtrip_expr() {
     let tests: Vec<(TableReference, &str, &str)> = vec![
-        (TableReference::bare("person"), "age > 35", "age > 35"),
-        (TableReference::bare("person"), "id = '10'", "id = '10'"),
+        (TableReference::bare("person"), "age > 35", "(age > 35)"),
+        (TableReference::bare("person"), "id = '10'", "(id = '10')"),
+        (TableReference::bare("person"), "CAST(id AS VARCHAR)", "CAST(id AS VARCHAR)"),
+        (TableReference::bare("person"), "SUM((age * 2))", "SUM((age * 2))"),
+
     ];
 
     let roundtrip = |table, sql: &str| -> Result<String> {
@@ -4540,15 +4543,15 @@ fn roundtrip_statement() {
         ),
         (
             "select ta.j1_id from j1 ta where ta.j1_id > 1;",
-            r#"SELECT ta.j1_id FROM j1 AS ta WHERE ta.j1_id > 1"#,
+            r#"SELECT ta.j1_id FROM j1 AS ta WHERE (ta.j1_id > 1)"#,
         ),
         (
-            "select ta.j1_id, tb.j2_string from j1 ta join j2 tb on ta.j1_id = tb.j2_id;",
-            r#"SELECT ta.j1_id, tb.j2_string FROM j1 AS ta JOIN j2 AS tb ON ta.j1_id = tb.j2_id"#,
+            "select ta.j1_id, tb.j2_string from j1 ta join j2 tb on (ta.j1_id = tb.j2_id);",
+            r#"SELECT ta.j1_id, tb.j2_string FROM j1 AS ta JOIN j2 AS tb ON (ta.j1_id = tb.j2_id)"#,
         ),
         (
-            "select ta.j1_id, tb.j2_string, tc.j3_string from j1 ta join j2 tb on ta.j1_id = tb.j2_id join j3 tc on ta.j1_id = tc.j3_id;",
-            r#"SELECT ta.j1_id, tb.j2_string, tc.j3_string FROM j1 AS ta JOIN j2 AS tb ON ta.j1_id = tb.j2_id JOIN j3 AS tc ON ta.j1_id = tc.j3_id"#,
+            "select ta.j1_id, tb.j2_string, tc.j3_string from j1 ta join j2 tb on (ta.j1_id = tb.j2_id) join j3 tc on (ta.j1_id = tc.j3_id);",
+            r#"SELECT ta.j1_id, tb.j2_string, tc.j3_string FROM j1 AS ta JOIN j2 AS tb ON (ta.j1_id = tb.j2_id) JOIN j3 AS tc ON (ta.j1_id = tc.j3_id)"#,
         ),
     ];