How to test my bench-marking functions?

Question

I have written benchmarking functions from my pallet. How I can test these benchmarking functions please?

Answer 1

You have to add the following line to your benchmarking. For example like in pallet-assets. Make sure to adjust it to your needs.

impl_benchmark_test_suite!(
    MyPallet,
    crate::mock::new_test_ext(),
    crate::mock::Test
)

This will create a unit test for each benchmark and run it a few times with different values for each component. Starting the tests looks like this:

cargo test -p pallet-whatever --features runtime-benchmarks

as described in the docs and README.md.
If you try this for example for the lottery pallet, you should see the following output:

test benchmarking::bench_start_lottery ... ok
test benchmarking::bench_stop_repeat ... ok
test benchmarking::bench_on_initialize_end ... ok
test benchmarking::bench_set_calls ... ok
test benchmarking::bench_buy_ticket ... ok
test benchmarking::bench_on_initialize_repeat ... ok

Each line is the output of one benchmark unit-test.
Please not that benchmark tests are no-std and that normally you cannot use functions from the mock.rs since it is std. You can, however, create a nostd_mock.rs with helper functions that are usable from tests and benchmarks.