From b43a89e4234fdc8df402b01b5bea38c6ed1b3eea Mon Sep 17 00:00:00 2001
From: Jussi Saurio <jussi.saurio@gmail.com>
Date: Sat, 27 Sep 2025 09:38:02 +0300
Subject: [PATCH] Add regression tests for ALTER TABLE stuff

---
 tests/integration/query_processing/mod.rs     |   1 +
 .../integration/query_processing/test_ddl.rs  | 134 ++++++++++++++++++
 2 files changed, 135 insertions(+)
 create mode 100644 tests/integration/query_processing/test_ddl.rs

diff --git a/tests/integration/query_processing/mod.rs b/tests/integration/query_processing/mod.rs
index 742cdf52c..fd30cac1e 100644
--- a/tests/integration/query_processing/mod.rs
+++ b/tests/integration/query_processing/mod.rs
@@ -1,4 +1,5 @@
 mod test_btree;
+mod test_ddl;
 mod test_read_path;
 mod test_write_path;
 
diff --git a/tests/integration/query_processing/test_ddl.rs b/tests/integration/query_processing/test_ddl.rs
new file mode 100644
index 000000000..990101973
--- /dev/null
+++ b/tests/integration/query_processing/test_ddl.rs
@@ -0,0 +1,134 @@
+use crate::common::TempDatabase;
+
+#[test]
+fn test_fail_drop_indexed_column() -> anyhow::Result<()> {
+    let _ = env_logger::try_init();
+    let tmp_db = TempDatabase::new_with_rusqlite("CREATE TABLE t (a, b);", true);
+    let conn = tmp_db.connect_limbo();
+
+    conn.execute("CREATE INDEX i ON t (a)")?;
+    let res = conn.execute("ALTER TABLE t DROP COLUMN a");
+    assert!(res.is_err(), "Expected error when dropping indexed column");
+    Ok(())
+}
+
+#[test]
+fn test_fail_drop_unique_column() -> anyhow::Result<()> {
+    let _ = env_logger::try_init();
+    let tmp_db = TempDatabase::new_with_rusqlite("CREATE TABLE t (a UNIQUE, b);", true);
+    let conn = tmp_db.connect_limbo();
+
+    let res = conn.execute("ALTER TABLE t DROP COLUMN a");
+    assert!(res.is_err(), "Expected error when dropping UNIQUE column");
+    Ok(())
+}
+
+#[test]
+fn test_fail_drop_compound_unique_column() -> anyhow::Result<()> {
+    let _ = env_logger::try_init();
+    let tmp_db = TempDatabase::new_with_rusqlite("CREATE TABLE t (a, b, UNIQUE(a, b));", true);
+    let conn = tmp_db.connect_limbo();
+
+    let res = conn.execute("ALTER TABLE t DROP COLUMN a");
+    assert!(
+        res.is_err(),
+        "Expected error when dropping column in compound UNIQUE"
+    );
+    Ok(())
+}
+
+#[test]
+fn test_fail_drop_primary_key_column() -> anyhow::Result<()> {
+    let _ = env_logger::try_init();
+    let tmp_db = TempDatabase::new_with_rusqlite("CREATE TABLE t (a PRIMARY KEY, b);", true);
+    let conn = tmp_db.connect_limbo();
+
+    let res = conn.execute("ALTER TABLE t DROP COLUMN a");
+    assert!(
+        res.is_err(),
+        "Expected error when dropping PRIMARY KEY column"
+    );
+    Ok(())
+}
+
+#[test]
+fn test_fail_drop_compound_primary_key_column() -> anyhow::Result<()> {
+    let _ = env_logger::try_init();
+    let tmp_db = TempDatabase::new_with_rusqlite("CREATE TABLE t (a, b, PRIMARY KEY(a, b));", true);
+    let conn = tmp_db.connect_limbo();
+
+    let res = conn.execute("ALTER TABLE t DROP COLUMN a");
+    assert!(
+        res.is_err(),
+        "Expected error when dropping column in compound PRIMARY KEY"
+    );
+    Ok(())
+}
+
+#[test]
+fn test_fail_drop_partial_index_column() -> anyhow::Result<()> {
+    let _ = env_logger::try_init();
+    let tmp_db = TempDatabase::new_with_rusqlite("CREATE TABLE t (a, b);", true);
+    let conn = tmp_db.connect_limbo();
+
+    conn.execute("CREATE INDEX i ON t (b) WHERE a > 0")?;
+    let res = conn.execute("ALTER TABLE t DROP COLUMN a");
+    assert!(
+        res.is_err(),
+        "Expected error when dropping column referenced by partial index"
+    );
+    Ok(())
+}
+
+#[test]
+fn test_fail_drop_view_column() -> anyhow::Result<()> {
+    let _ = env_logger::try_init();
+    let tmp_db = TempDatabase::new_with_rusqlite("CREATE TABLE t (a, b);", true);
+    let conn = tmp_db.connect_limbo();
+
+    conn.execute("CREATE VIEW v AS SELECT a, b FROM t")?;
+    let res = conn.execute("ALTER TABLE t DROP COLUMN a");
+    assert!(
+        res.is_err(),
+        "Expected error when dropping column referenced by view"
+    );
+    Ok(())
+}
+
+// FIXME: this should rewrite the view to reference the new column name
+#[test]
+fn test_fail_rename_view_column() -> anyhow::Result<()> {
+    let _ = env_logger::try_init();
+    let tmp_db = TempDatabase::new_with_rusqlite("CREATE TABLE t (a, b);", true);
+    let conn = tmp_db.connect_limbo();
+
+    conn.execute("CREATE VIEW v AS SELECT a, b FROM t")?;
+    let res = conn.execute("ALTER TABLE t RENAME a TO c");
+    assert!(
+        res.is_err(),
+        "Expected error when renaming column referenced by view"
+    );
+    Ok(())
+}
+
+#[test]
+fn test_allow_drop_unreferenced_columns() -> anyhow::Result<()> {
+    let _ = env_logger::try_init();
+    let tmp_db = TempDatabase::new_with_rusqlite(
+        "CREATE TABLE t (pk INTEGER PRIMARY KEY, indexed INTEGER, viewed INTEGER, partial INTEGER, compound1 INTEGER, compound2 INTEGER, unused1 INTEGER, unused2 INTEGER, unused3 INTEGER);",
+        true
+    );
+    let conn = tmp_db.connect_limbo();
+
+    conn.execute("CREATE INDEX idx ON t(indexed)")?;
+    conn.execute("CREATE VIEW v AS SELECT viewed FROM t")?;
+    conn.execute("CREATE INDEX partial_idx ON t(compound1) WHERE partial > 0")?;
+    conn.execute("CREATE INDEX compound_idx ON t(compound1, compound2)")?;
+
+    // Should be able to drop unused columns
+    conn.execute("ALTER TABLE t DROP COLUMN unused1")?;
+    conn.execute("ALTER TABLE t DROP COLUMN unused2")?;
+    conn.execute("ALTER TABLE t DROP COLUMN unused3")?;
+
+    Ok(())
+}