Println to debug integration tests?

help
1

Maybe strange question, but I want to debug some tests (for myself) with temporary println! macro, but seems I can operate with assert only.

Can I use println! in tests for output or that's wrong idea even for development needs?

2

By default, the test harness hides all output from println and friends unless the test fails. Your options are:

  • Make the test fail in addition to your printlns.
  • Use the --show-output option, to show output even from failing tests.
  • Use the --nocapture option, to not capture output at all (this means that unless you are running exactly one test, output from multiple threadswill be interleaved).

Such test options need to be explicitly passed to the test binary and not Cargo, like this:

cargo test -- --show-output

or

cargo test --test my_integration_test -- --nocapture my_test_function_name
1 Like
3

Thank you much!