---
title: assert_called (subscriber assertions)
sidebar_label: assert_called
sidebar_position: 2
description: "assert_called(n) checks that a subscriber's handler ran exactly n times, counting a batch as one call."
---
import Tabs from '@theme/Tabs';
import TabItem from '@theme/TabItem';
# assert_called
[`assert_called(n)`](api:ruststream::testing::SubscriberAssertions::assert_called) checks that a subscriber's handler ran exactly `n` times, counting a batch as one call.
`n` is the number of handler calls.
A single-message handler is called once per delivery, and once more for each redelivery.
A batch handler is called once per batch, so here `n` counts batches; [`assert_batch_sizes`](./assert-batch-sizes.md) shows how big each one was.
A publish through the harness runs to completion before it returns, so three publishes make three calls.
On failure it panics with the number of calls it found.
[`assert_called_once`](./assert-called-once.md) is the same check for one call, and [`outcomes`](./outcomes.md) shows how each call settled.
A destination's [`assert_called(n)`](../published-assertions/assert-called.md) counts publishes instead.
## Example
<Tabs groupId="api">
<TabItem value="macros" label="Macros">
```rust reference="examples/testing_subscriber_calls.rs#assert_called"
```
</TabItem>
<TabItem value="manual" label="Manual">
```rust reference="examples/manual/testing_subscriber_calls.rs#assert_called"
```
</TabItem>
</Tabs>