diff --git a/src/frontend/src/handler/alter_source_column.rs b/src/frontend/src/handler/alter_source_column.rs
index 385fc34dba44a..ef91e011365e7 100644
--- a/src/frontend/src/handler/alter_source_column.rs
+++ b/src/frontend/src/handler/alter_source_column.rs
@@ -171,10 +171,9 @@ pub fn alter_definition_add_column(definition: &str, column: ColumnDef) -> Resul
 
 #[cfg(test)]
 pub mod tests {
-    use std::collections::HashMap;
+    use std::collections::BTreeMap;
 
     use risingwave_common::catalog::{DEFAULT_DATABASE_NAME, DEFAULT_SCHEMA_NAME};
-    use risingwave_common::types::DataType;
 
     use crate::catalog::root_catalog::SchemaPath;
     use crate::test_utils::LocalFrontend;
@@ -211,47 +210,103 @@ pub mod tests {
             .await
             .unwrap();
 
-        let get_source = || {
+        let get_source = |name: &str| {
             let catalog_reader = session.env().catalog_reader().read_guard();
             catalog_reader
-                .get_source_by_name(DEFAULT_DATABASE_NAME, schema_path, "s")
+                .get_source_by_name(DEFAULT_DATABASE_NAME, schema_path, name)
                 .unwrap()
                 .0
                 .clone()
         };
 
-        let source = get_source();
-        let columns: HashMap<_, _> = source
+        let source = get_source("s");
+
+        let sql = "alter source s_shared add column v2 varchar;";
+        frontend.run_sql(sql).await.unwrap();
+
+        let altered_source = get_source("s_shared");
+        let altered_columns: BTreeMap<_, _> = altered_source
             .columns
             .iter()
             .map(|col| (col.name(), (col.data_type().clone(), col.column_id())))
             .collect();
 
-        let sql = "alter source s_shared add column v2 varchar;";
-        assert_eq!("Feature is not yet implemented: alter shared source\nTracking issue: https://github.com/risingwavelabs/risingwave/issues/16003", &frontend.run_sql(sql).await.unwrap_err().to_string());
+        // Check the new column is added.
+        // Check the old columns and IDs are not changed.
+        expect_test::expect![[r#"
+            {
+                "_row_id": (
+                    Serial,
+                    #0,
+                ),
+                "_rw_kafka_offset": (
+                    Varchar,
+                    #4,
+                ),
+                "_rw_kafka_partition": (
+                    Varchar,
+                    #3,
+                ),
+                "_rw_kafka_timestamp": (
+                    Timestamptz,
+                    #2,
+                ),
+                "v1": (
+                    Int32,
+                    #1,
+                ),
+                "v2": (
+                    Varchar,
+                    #5,
+                ),
+            }
+        "#]]
+        .assert_debug_eq(&altered_columns);
+
+        // Check version
+        assert_eq!(source.version + 1, altered_source.version);
+
+        // Check definition
+        expect_test::expect!["CREATE SOURCE s_shared (v1 INT, v2 CHARACTER VARYING) WITH (connector = 'kafka', topic = 'abc', properties.bootstrap.server = 'localhost:29092') FORMAT PLAIN ENCODE JSON"].assert_eq(&altered_source.definition);
+
         let sql = "alter source s add column v2 varchar;";
         frontend.run_sql(sql).await.unwrap();
 
-        let altered_source = get_source();
-
-        let altered_columns: HashMap<_, _> = altered_source
+        let altered_source = get_source("s");
+        let altered_columns: BTreeMap<_, _> = altered_source
             .columns
             .iter()
             .map(|col| (col.name(), (col.data_type().clone(), col.column_id())))
             .collect();
 
-        // Check the new column.
-        assert_eq!(columns.len() + 1, altered_columns.len());
-        assert_eq!(altered_columns["v2"].0, DataType::Varchar);
-
+        // Check the new column is added.
         // Check the old columns and IDs are not changed.
-        assert_eq!(columns["v1"], altered_columns["v1"]);
+        expect_test::expect![[r#"
+            {
+                "_row_id": (
+                    Serial,
+                    #0,
+                ),
+                "_rw_kafka_timestamp": (
+                    Timestamptz,
+                    #2,
+                ),
+                "v1": (
+                    Int32,
+                    #1,
+                ),
+                "v2": (
+                    Varchar,
+                    #3,
+                ),
+            }
+        "#]]
+        .assert_debug_eq(&altered_columns);
 
         // Check version
         assert_eq!(source.version + 1, altered_source.version);
 
         // Check definition
-        let altered_sql = r#"CREATE SOURCE s (v1 INT, v2 CHARACTER VARYING) WITH (connector = 'kafka', topic = 'abc', properties.bootstrap.server = 'localhost:29092') FORMAT PLAIN ENCODE JSON"#;
-        assert_eq!(altered_sql, altered_source.definition);
+        expect_test::expect!["CREATE SOURCE s (v1 INT, v2 CHARACTER VARYING) WITH (connector = 'kafka', topic = 'abc', properties.bootstrap.server = 'localhost:29092') FORMAT PLAIN ENCODE JSON"].assert_eq(&altered_source.definition);
     }
 }