Ensure Bank timestamp always increases, and make test less brittle

runtime/src/bank.rs

@@ -69,6 +69,7 @@ use solana_stake_program::stake_state::{self, Delegation, PointValue};
 use solana_vote_program::{vote_instruction::VoteInstruction, vote_state::VoteState};
 use std::{
  cell::RefCell,
+ cmp::max,
  collections::{HashMap, HashSet},
  convert::{TryFrom, TryInto},
  mem,
@@ -1385,7 +1386,7 @@ impl Bank {
 
  EpochTimestamps {
  first_slot: self.slot,
- timestamp: epoch_timestamp,
+ timestamp: max(epoch_timestamp, self.unix_timestamp_from_genesis()),
  ..EpochTimestamps::default()
  }
  .create_account(self.inherit_sysvar_account_balance(account))
@@ -9507,11 +9508,16 @@ mod tests {
  genesis_config.epoch_schedule = EpochSchedule::new(32);
  let mut bank = Arc::new(Bank::new(&genesis_config));
  let recent_timestamp: UnixTimestamp = bank.unix_timestamp_from_genesis();
+ let slot_duration = Duration::from_nanos(bank.ns_per_slot as u64);
 
+ let timestamp_slot_12 = recent_timestamp + (12 * slot_duration).as_secs() as i64;
+ let timestamp_slot_22 = recent_timestamp + (22 * slot_duration).as_secs() as i64;
+ let slowdown_secs = 4;
+ let timestamp_slot_22 = timestamp_slot_22 + slowdown_secs;
  bank.update_sysvar_account(&sysvar::epoch_timestamps::id(), |account| {
  let mut samples = HashMap::new();
- samples.insert(12, Some(recent_timestamp));
- samples.insert(22, Some(recent_timestamp + 6));
+ samples.insert(12, Some(timestamp_slot_12));
+ samples.insert(22, Some(timestamp_slot_22));
 
  EpochTimestamps {
  first_slot: bank.slot,
@@ -9528,7 +9534,10 @@ mod tests {
  )
  .unwrap();
  assert_eq!(epoch_timestamps.first_slot, bank.slot());
- assert_eq!(epoch_timestamps.timestamp, recent_timestamp + 9);
+ assert_eq!(
+ epoch_timestamps.timestamp,
+ bank.unix_timestamp_from_genesis() + (slowdown_secs / 2)
+ );
  assert!(epoch_timestamps.samples.is_empty());
  }