message: Pass the rng to `build` method.
diff: @@ -665,7 +665,7 @@ impl<C: Context<ValidatorId = ValidatorId>, DS: DeliveryStrategy<C>>
  self
  }
  - fn build(mut self) -> Result<HighwayTestHarness<C, DS>, BuilderError> {
  + fn build<R: Rng>(mut self, rng: &mut R) -> Result<HighwayTestHarness<C, DS>, BuilderError> {
  if self.validators_secs.is_empty() {
  return Err(BuilderError::NoValidators);
  }
  @@ -878,7 +878,7 @@ mod test_harness {
  .consensus_values(vec![1])
  .weight_limits(1, 5)
  .ftt(1)
  - .build()
  + .build(&mut rand)
  .ok()
  .expect("Construction was successful");
  @@ -905,7 +905,7 @@ mod test_harness {
  .validators(validators)
  .consensus_values((0..10).collect())
  .weight_limits(3, 5)
  - .build()
  + .build(&mut rand)
  .ok()
  .expect("Construction was successful");
  