message: add random commits in proptest
diff: @@ -1338,12 +1338,14 @@ mod tests {
  enum IndexingOp {
  AddDoc { id: u64 },
  DeleteDoc { id: u64 },
  + Commit,
  }
  fn operation_strategy() -> impl Strategy<Value = IndexingOp> {
  prop_oneof![
  (0u64..10u64).prop_map(|id| IndexingOp::DeleteDoc { id }),
  (0u64..10u64).prop_map(|id| IndexingOp::AddDoc { id }),
  + (0u64..2u64).prop_map(|_| IndexingOp::Commit ),
  ]
  }
  @@ -1357,6 +1359,7 @@ mod tests {
  IndexingOp::DeleteDoc { id } => {
  ids.retain(|&id_val| id_val != id);
  }
  + _ => {}
  }
  }
  ids.sort();
  @@ -1387,11 +1390,14 @@ mod tests {
  IndexingOp::DeleteDoc { id } => {
  index_writer.delete_term(Term::from_field_u64(id_field, id));
  }
  + IndexingOp::Commit => {
  + index_writer.commit()?;
  + }
  }
  }
  index_writer.commit()?;
  let searcher = index.reader()?.searcher();
  - let ids: Vec<u64> = searcher
  + let mut ids: Vec<u64> = searcher
  .segment_readers()
  .iter()
  .flat_map(|segment_reader| {
  @@ -1401,6 +1407,7 @@ mod tests {
  .map(move |doc| ff_reader.get(doc))
  })
  .collect();
  + ids.sort();
  assert_eq!(ids, expected_ids(ops));
  Ok(())
  