Address PR review: soften runs-across comment, randomize names, add alias cleanup

Signed-off-by: Eric Wei <mengwei.eric@gmail.com>

Author: mengweieric

integ-test/src/test/java/org/opensearch/sql/sql/VectorSearchIT.java

@@ -671,23 +671,24 @@ public void testTrailingCommaInVectorRejected() throws IOException {
 
   // ── Alias with multiple backing indices ───────────────────────────────
   // vectorSearch() accepts an alias as `table=`. When the alias points at multiple backing
-  // indices with matching knn_vector mappings, planning must succeed — the query then runs
-  // across all backing indices just like a regular alias query. Execution requires the k-NN
-  // plugin, which is not installed on the default integ-test cluster, so these tests verify
-  // the planning path via _explain only.
+  // indices, planning must accept the alias string instead of treating it as a wildcard or
+  // multi-target. Execution correctness over compatible knn_vector mappings is a separate
+  // concern covered by k-NN-enabled tests/follow-up; these tests lock in planning acceptance
+  // only, via _explain on the default no-kNN cluster.
 
   @Test
   public void testExplainOverAliasWithMultipleBackingIndices() throws IOException {
     // Create two indices with identical keyword mappings (no knn_vector, since the plugin is
     // not installed) and a shared alias. We only assert the planner accepts the alias; whether
     // k-NN accepts the alias at execution is a separate concern tested on a k-NN-enabled
     // cluster.
-    String idx1 = "vector_alias_backing_1";
-    String idx2 = "vector_alias_backing_2";
-    String alias = "vector_alias_combined";
+    // Randomized names so a stale alias/index left by an aborted prior run of this class does
+    // not shadow a fresh setup — a concrete risk on local reruns.
+    String suffix = java.util.UUID.randomUUID().toString().replace("-", "").substring(0, 8);
+    String idx1 = "vector_alias_backing_1_" + suffix;
+    String idx2 = "vector_alias_backing_2_" + suffix;
+    String alias = "vector_alias_combined_" + suffix;
     try {
-      deleteIndexIfExists(idx1);
-      deleteIndexIfExists(idx2);
       createSimpleIndex(idx1);
       createSimpleIndex(idx2);
       addToAlias(idx1, alias);
@@ -702,6 +703,9 @@ public void testExplainOverAliasWithMultipleBackingIndices() throws IOException
       assertThat(explain, containsString("VectorSearchIndexScan"));
       assertThat(explain, containsString(alias));
     } finally {
+      // Deleting the backing indices removes the alias automatically, but delete the alias
+      // first for robustness against partial setup failures.
+      deleteAliasIfExists(alias);
       deleteIndexIfExists(idx1);
       deleteIndexIfExists(idx2);
     }
@@ -731,4 +735,12 @@ private void deleteIndexIfExists(String indexName) {
       // Index does not exist, which is fine.
     }
   }
+
+  private void deleteAliasIfExists(String aliasName) {
+    try {
+      client().performRequest(new Request("DELETE", "/_all/_alias/" + aliasName));
+    } catch (IOException ignored) {
+      // Alias does not exist, which is fine.
+    }
+  }
 }