[WIP] Fix DF cast pushdown

vortex-datafusion/src/lib.rs

@@ -46,3 +46,47 @@ where
         }
     }
 }
+
+#[cfg(test)]
+mod tests {
+
+    use std::sync::Arc;
+
+    use datafusion::{
+        execution::SessionStateBuilder,
+        prelude::{SessionConfig, SessionContext},
+    };
+
+    use crate::VortexFormatFactory;
+
+    // https://github.com/vortex-data/vortex/issues/6211
+    #[tokio::test]
+    async fn test_cast_int_to_string() -> anyhow::Result<()> {
+        let ctx = {
+            let s = SessionStateBuilder::new()
+                .with_file_formats(vec![Arc::new(VortexFormatFactory::new())])
+                .with_config(SessionConfig::from_env()?)
+                .with_runtime_env(Default::default())
+                .with_default_features()
+                .build();
+            SessionContext::new_with_state(s).enable_url_table()
+        };
+
+        ctx.sql(r#"copy (select 1 as id) to 'example.vortex'"#)
+            .await?
+            .show()
+            .await?;
+
+        ctx.sql(r#"select cast(id as string) as sid from 'example.vortex' where id > 0"#)
+            .await?
+            .show()
+            .await?;
+
+        ctx.sql(r#"select id from 'example.vortex' where cast (id as string) == '1'"#)
+            .await?
+            .show()
+            .await?;
+
+        Ok(())
+    }
+}