defmt-test: Fix #[ignore] attribute

[liam-b]

It seems to know that the test should be ignored but runs it anyway. I have a minimal reproducible example repo based on the app template modified for the Pixhawk 6C (running an STM32H743).

I did have to move defmt-rtt to version 0.3 because of #713 and I couldn't get flip-link working yet so it is disabled.

Running cargo test --test integration gives me:

   Compiling defmt-test-ignore-bug v0.1.0 (/Users/liam/src/tmp/defmt-test-ignore-bug)
    Finished test [optimized + debuginfo] target(s) in 0.71s
     Running tests/integration.rs (target/thumbv7em-none-eabihf/debug/deps/integration-7afe1656c338520d)
(HOST) INFO  flashing program (8 pages / 8.00 KiB)
(HOST) INFO  success!
────────────────────────────────────────────────────────────────────────────────
(1/2) running `it_works`...
└─ integration::tests::__defmt_test_entry @ tests/integration.rs:13
(2/2) ignoring `it_does_not_work`...
└─ integration::tests::__defmt_test_entry @ tests/integration.rs:19
ERROR panicked at 'should be ignored'
└─ integration::tests::it_does_not_work @ tests/integration.rs:20
────────────────────────────────────────────────────────────────────────────────
(HOST) WARN  no RAM region appears to contain the stack; probe-run can't determine if this was a stack overflow
stack backtrace:
   0: HardFaultTrampoline
      <exception entry>
   1: lib::inline::__udf
        at ./asm/inline.rs:181:5
   2: __udf
        at ./asm/lib.rs:51:17
   3: cortex_m::asm::udf
        at /Users/liam/.cargo/registry/src/github.com-1ecc6299db9ec823/cortex-m-0.7.7/src/asm.rs:43:5
   4: _defmt_panic
        at src/lib.rs:14:5
   5: main
   6: Reset
(HOST) ERROR the program panicked
error: test failed, to rerun pass `--test integration`

Caused by:
  process didn't exit successfully: `probe-run --chip STM32H743VIHx /Users/liam/src/tmp/defmt-test-ignore-bug/target/thumbv7em-none-eabihf/debug/deps/integration-7afe1656c338520d` (exit status: 6)

[Urhengulas]

Hi @liam-b, defmt-test doesn't support a #[ignore] attribute at the moment. See https://crates.io/crates/defmt-test regarding what defmt-test can and cannot do.

If you implement it, I am happy to review and merge.

[jonas-schievink]

#618 implemented support for #[ignore], but has a bug where the function will be run regardless: #618 (comment)

[Urhengulas]

A call to the ignored function is currently added here:

defmt/firmware/defmt-test/macros/src/lib.rs

Lines 372 to 373 in f5315e0

	if ignore {
	unit_test_calls.push(quote!(let _ = #call;));

Instead there should be no call, but we should print that the test is ignored.

You can print with quote!{ defmt::println!(...) }.