Add tests for end; clause in query pipelines (#432)

## Product change and motivation

Add tests for `end;` statements

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

Author: flyingsilverfin

rust/parser/test/pipeline.rs

@@ -103,3 +103,76 @@ fetch {
     let parsed = parse_queries(queries).unwrap();
     assert_eq!(parsed.len(), 4);
 }
+
+#[test]
+fn test_single_pipeline_with_optional_end() {
+    // end; is optional for a single pipeline
+    let query_without_end = r#"match
+$x isa movie;
+insert
+$x has rating 5;"#;
+    let parsed_without = parse_query(query_without_end).unwrap();
+    assert!(!parsed_without.has_explicit_end());
+
+    let query_with_end = r#"match
+$x isa movie;
+insert
+$x has rating 5;
+end;"#;
+    let parsed_with = parse_query(query_with_end).unwrap();
+    assert!(parsed_with.has_explicit_end());
+
+    // parse_queries with a single query should return exactly one query
+    // and it should be equivalent to parse_query
+    let parsed_queries = parse_queries(query_with_end).unwrap();
+    assert_eq!(parsed_queries.len(), 1);
+    assert!(parsed_queries[0].has_explicit_end());
+    assert_eq!(parsed_with.to_string(), parsed_queries[0].to_string());
+}
+
+#[test]
+fn test_schema_query_with_optional_end() {
+    // end; is optional for schema queries
+    let query_without_end = r#"define
+entity movie;"#;
+    let parsed_without = parse_query(query_without_end).unwrap();
+    assert!(!parsed_without.has_explicit_end());
+
+    let query_with_end = r#"define
+entity movie;
+end;"#;
+    let parsed_with = parse_query(query_with_end).unwrap();
+    assert!(parsed_with.has_explicit_end());
+}
+
+#[test]
+fn test_all_pipeline_stages_with_end() {
+    // Various pipeline stage combinations with end;
+    let queries = r#"match
+$x isa person;
+end;
+
+match
+$x isa person;
+select $x;
+end;
+
+match
+$x isa person;
+delete $x;
+end;
+
+match
+$x isa person, has name $n;
+reduce $count = count($n);
+end;
+
+insert
+$x isa person, has name "Alice";
+end;"#;
+    let parsed = parse_queries(queries).unwrap();
+    assert_eq!(parsed.len(), 5);
+    for i in 0..5 {
+        assert!(parsed[i].has_explicit_end(), "Query {} should have explicit end", i);
+    }
+}