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# core::starknet::testing::set_chain_id

Set the transaction chain id.

## Signature

```rust theme={null}
pub fn set_chain_id(chain_id: felt252)
```

#### Arguments

`chain_id` - The chain id to set.
After a call to `set_chain_id`, `starknet::get_execution_info().tx_info.chain_id` will return
the set value.