test(cubesql): More tests for LIMIT 0

Author: mcheshkov

rust/cubesql/cubesql/src/compile/test/test_cube_scan.rs

@@ -224,3 +224,120 @@ async fn cubescan_limit_offset_limit_offset() {
         );
     }
 }
+
+/// Test that LIMIT 0 is pushed to grouped CubeScan
+#[tokio::test]
+async fn cubescan_limit_zero() {
+    init_testing_logger();
+
+    let query_plan = convert_select_to_query_plan(
+        // language=PostgreSQL
+        r#"
+        SELECT
+            customer_gender
+        FROM
+            KibanaSampleDataEcommerce
+        GROUP BY
+            1
+        LIMIT 0
+        "#
+        .to_string(),
+        DatabaseProtocol::PostgreSQL,
+    )
+    .await;
+
+    let logical_plan = query_plan.as_logical_plan();
+    assert_eq!(
+        logical_plan.find_cube_scan().request,
+        V1LoadRequestQuery {
+            measures: Some(vec![]),
+            dimensions: Some(vec!["KibanaSampleDataEcommerce.customer_gender".to_string()]),
+            segments: Some(vec![]),
+            order: Some(vec![]),
+            limit: Some(0),
+            ..Default::default()
+        }
+    );
+}
+
+/// Test that LIMIT 0 is pushed to ungrouped CubeScan
+#[tokio::test]
+async fn cubescan_ungrouped_limit_zero() {
+    init_testing_logger();
+
+    let query_plan = convert_select_to_query_plan(
+        // language=PostgreSQL
+        r#"
+        SELECT
+            customer_gender
+        FROM
+            KibanaSampleDataEcommerce
+        LIMIT 0
+        "#
+        .to_string(),
+        DatabaseProtocol::PostgreSQL,
+    )
+    .await;
+
+    let logical_plan = query_plan.as_logical_plan();
+    assert_eq!(
+        logical_plan.find_cube_scan().request,
+        V1LoadRequestQuery {
+            measures: Some(vec![]),
+            dimensions: Some(vec!["KibanaSampleDataEcommerce.customer_gender".to_string()]),
+            segments: Some(vec![]),
+            order: Some(vec![]),
+            limit: Some(0),
+            ungrouped: Some(true),
+            ..Default::default()
+        }
+    );
+}
+
+/// Test that LIMIT 0 is pushed to CubeScan for SELECT *
+#[tokio::test]
+async fn cubescan_star_limit_zero() {
+    init_testing_logger();
+
+    let query_plan = convert_select_to_query_plan(
+        // language=PostgreSQL
+        r#"
+        SELECT
+            *
+        FROM
+            KibanaSampleDataEcommerce
+        LIMIT 0
+        "#
+        .to_string(),
+        DatabaseProtocol::PostgreSQL,
+    )
+    .await;
+
+    let logical_plan = query_plan.as_logical_plan();
+    assert_eq!(
+        logical_plan.find_cube_scan().request,
+        V1LoadRequestQuery {
+            measures: Some(vec![
+                "KibanaSampleDataEcommerce.count".to_string(),
+                "KibanaSampleDataEcommerce.maxPrice".to_string(),
+                "KibanaSampleDataEcommerce.sumPrice".to_string(),
+                "KibanaSampleDataEcommerce.minPrice".to_string(),
+                "KibanaSampleDataEcommerce.avgPrice".to_string(),
+                "KibanaSampleDataEcommerce.countDistinct".to_string(),
+            ]),
+            dimensions: Some(vec![
+                "KibanaSampleDataEcommerce.order_date".to_string(),
+                "KibanaSampleDataEcommerce.last_mod".to_string(),
+                "KibanaSampleDataEcommerce.customer_gender".to_string(),
+                "KibanaSampleDataEcommerce.notes".to_string(),
+                "KibanaSampleDataEcommerce.taxful_total_price".to_string(),
+                "KibanaSampleDataEcommerce.has_subscription".to_string(),
+            ]),
+            segments: Some(vec![]),
+            order: Some(vec![]),
+            limit: Some(0),
+            ungrouped: Some(true),
+            ..Default::default()
+        }
+    );
+}