//! Measurement of gas consumption for testing purpose.

//!

//! This module provides the `get_available_gas` function, useful for asserting the amount of gas

//! consumed by a particular operation or function call.

//! By calling `get_available_gas` before and after the operation, you can calculate the exact

//! amount of gas used.

use crate::gas::GasBuiltin;

/// Returns the amount of gas available in the `GasBuiltin`.

///

/// Useful for asserting that a certain amount of gas was consumed.

/// Note: The actual gas consumption observed by calls to `get_available_gas` is only exact

/// immediately before calls to `withdraw_gas`.

///

/// # Examples

///

/// ```

/// use core::testing::get_available_gas;

///

/// fn gas_heavy_function() {

/// // ... some gas-intensive code

/// }

///

/// fn test_gas_consumption() {

/// let gas_before = get_available_gas();

/// // Making sure `gas_before` is exact.

/// core::gas::withdraw_gas().unwrap();

///

/// gas_heavy_function();

///

/// let gas_after = get_available_gas();

/// // Making sure `gas_after` is exact

/// core::gas::withdraw_gas().unwrap();

///

/// assert!(gas_before - gas_after < 100_000);

/// }

/// ```

pub extern fn get_available_gas() -> u128 implicits(GasBuiltin) nopanic;

/// Returns the amount of gas available in the `GasBuiltin`, as well as the amount of gas unused in

/// the local wallet.

///

/// Useful for asserting that a certain amount of gas was used.

/// Note: This function call costs exactly `2300` gas, so this may be ignored in calculations.

/// # Examples

///

/// ```

/// use core::testing::get_unspent_gas;

///

/// fn gas_heavy_function() {

/// // ... some gas-intensive code

/// }

///

/// fn test_gas_consumption() {

/// let gas_before = get_unspent_gas();

/// gas_heavy_function();

/// let gas_after = get_unspent_gas();

/// assert!(gas_before - gas_after < 100_000);

/// }

/// ```

pub extern fn get_unspent_gas() -> u128 implicits(GasBuiltin) nopanic;