test: add test for empty arr in subgaph feature query

Author: shiyasmohd

tests/tests/integration_tests.rs

@@ -838,6 +838,42 @@ async fn test_non_fatal_errors(ctx: TestContext) -> anyhow::Result<()> {
     Ok(())
 }
 
+async fn test_empty_subgraph_features(ctx: TestContext) -> anyhow::Result<()> {
+    let subgraph = ctx.subgraph;
+    let query = "query GetEmptySubgraphFeatures() {
+        subgraphFeatures(subgraphs: []) {
+          subgraph
+          specVersion
+          apiVersion
+          features
+          dataSources
+          network
+          handlers
+        }
+      }";
+
+    let resp = subgraph.query(query).await?;
+
+    // The response is now an array, get the first element
+    let features_array = &resp["data"]["subgraphFeatures"];
+    assert!(
+        features_array.is_array(),
+        "subgraphFeatures must return an array"
+    );
+    assert_eq!(
+        features_array.as_array().unwrap().len(),
+        0,
+        "Expected exactly zero subgraph feature set"
+    );
+
+    let exp = json!({
+        "subgraphFeatures": []
+    });
+    assert_eq!(&exp, &resp["data"]);
+
+    Ok(())
+}
+
 async fn test_overloaded_functions(ctx: TestContext) -> anyhow::Result<()> {
     let subgraph = ctx.subgraph;
     // all overloads of the contract function are called
@@ -1132,6 +1168,7 @@ async fn integration_tests() -> anyhow::Result<()> {
         TestCase::new("reverted-calls", test_reverted_calls_are_indexed),
         TestCase::new("host-exports", test_host_exports),
         TestCase::new("non-fatal-errors", test_non_fatal_errors),
+        TestCase::new("non-fatal-errors", test_empty_subgraph_features),
         TestCase::new("overloaded-functions", test_overloaded_functions),
         TestCase::new("poi-for-failed-subgraph", test_poi_for_failed_subgraph),
         TestCase::new("remove-then-update", test_remove_then_update),