---
title: Time Travel
description:
  Jump the Surfnet clock forward to an absolute slot, epoch, or Unix timestamp.
  Useful for tests that exercise vesting schedules, lockups, expiration windows,
  or epoch boundaries.
---

The Surfpool runtime exposes three time-travel helpers. Each one moves the local
clock to an absolute target (not a relative offset) and returns the updated
`EpochInfo` so tests can assert that the runtime actually reached the requested
time.

| Helper                                               | Target                         | Returns                                  |
| ---------------------------------------------------- | ------------------------------ | ---------------------------------------- |
| `time_travel_to_slot` / `timeTravelToSlot`           | Absolute slot number           | `EpochInfo` with the new `absolute_slot` |
| `time_travel_to_epoch` / `timeTravelToEpoch`         | Absolute epoch number          | `EpochInfo` with the new `epoch`         |
| `time_travel_to_timestamp` / `timeTravelToTimestamp` | Unix timestamp in milliseconds | `EpochInfo` reflecting the implied slot  |

<Callout type="warn" title="Forward only">
  Time travel can only move the clock **forward**. Calling these methods with a
  target in the past is a no-op — the helper returns the current `EpochInfo`
  unchanged.
</Callout>

## Jump To A Slot

<CodeTabs storage="surfpool-lang">

```rust !! title="Rust"
use surfpool_sdk::Surfnet;

let surfnet = Surfnet::start().await?;
let cheats = surfnet.cheatcodes();

let info = cheats.time_travel_to_slot(1_000_000)?;
assert!(info.absolute_slot >= 1_000_000);
```

```ts !! title="TypeScript"
import { Surfnet } from "@solana/surfpool";

const surfnet = Surfnet.start();
try {
  const info = surfnet.timeTravelToSlot(1_000_000);
  console.assert(info.absoluteSlot >= 1_000_000);
} finally {
  surfnet.stop();
}
```

</CodeTabs>

## Jump To An Epoch

<CodeTabs storage="surfpool-lang">

```rust !! title="Rust"
let info = cheats.time_travel_to_epoch(420)?;
assert_eq!(info.epoch, 420);
```

```ts !! title="TypeScript"
const info = surfnet.timeTravelToEpoch(420);
console.assert(info.epoch === 420);
```

</CodeTabs>

## Jump To A Unix Timestamp

Pass the timestamp in **milliseconds**, not seconds. The runtime computes the
closest slot at that timestamp.

<CodeTabs storage="surfpool-lang">

```rust !! title="Rust"
// 2030-01-01T00:00:00Z
let info = cheats.time_travel_to_timestamp(1_893_456_000_000)?;
```

```ts !! title="TypeScript"
// 2030-01-01T00:00:00Z
const info = surfnet.timeTravelToTimestamp(1_893_456_000_000);
```

</CodeTabs>

## Common Patterns

### Test A Lockup Or Vesting Window

The example below is a sketch — `assertWithdrawFails` and
`assertWithdrawSucceeds` are placeholders for whatever client-side helpers your
test suite uses to assert on RPC behavior.

```ts
import { Surfnet } from "@solana/surfpool";

const surfnet = Surfnet.start();
const beneficiary = Surfnet.newKeypair();

// 1. Set up a vesting account that unlocks at slot 1,000,000.
surfnet.setAccount(/* ...lockup program state... */);

// 2. Verify withdrawal fails before unlock.
await assertWithdrawFails(surfnet.rpcUrl, beneficiary);

// 3. Travel past the unlock slot.
surfnet.timeTravelToSlot(1_000_001);

// 4. Verify withdrawal succeeds.
await assertWithdrawSucceeds(surfnet.rpcUrl, beneficiary);

surfnet.stop();
```

### Drive A Multi-Epoch Scenario

<Callout type="warn" title="Intermediate slots are skipped">
  Time travel jumps directly to the target — moving from epoch 1 to epoch 5
  skips the slots in between. If your program needs each intermediate epoch
  boundary to fire (for example, to credit per-epoch rewards), call
  `time_travel_to_epoch` once per epoch with any required transactions in
  between.
</Callout>

```rust
for epoch in 2..=5 {
    cheats.time_travel_to_epoch(epoch)?;
    surfnet.rpc_client().send_transaction(&claim_rewards_tx)?;
}
```

## EpochInfo Shape

Both SDKs return an `EpochInfo`-shaped object with these fields:

| Field             | Rust                             | JS                          |
| ----------------- | -------------------------------- | --------------------------- |
| Absolute slot     | `absolute_slot: u64`             | `absoluteSlot: number`      |
| Slot within epoch | `slot_index: u64`                | `slotIndex: number`         |
| Slots per epoch   | `slots_in_epoch: u64`            | `slotsInEpoch: number`      |
| Epoch number      | `epoch: u64`                     | `epoch: number`             |
| Block height      | `block_height: u64`              | `blockHeight: number`       |
| Transaction count | `transaction_count: Option<u64>` | `transactionCount?: number` |