Comments for "https://os.phil-opp.com/testing/"

[utterances-bot]

This is a general purpose comment thread for the Testing post.

[leggettc18]

I'm not sure if I did something wrong, but by following along with this guide exactly I was receiving an error about fmt being undeclared after setting up the CompareMessage implementation. I fixed it by adding use core::fmt; and use core::fmt::Write; at the top of the file, and increasing the PANIC_LINE by 2 to compensate. Did I miss a step along the way or is there a missing step in the guide?

[phil-opp]

@leggettc18 You did nothing wrong, I forgot to mention these imports. Fixed in 1f97103. Thanks for reporting!

[Lorithan]

I'm unable to run cargo xtest. Instead I keep keeping the message

error[E0463]: can't find crate for std
|
= note: the x86_64-blog_os-1954185736335484285 target may not be installed

cargo xbuild works fine, though.

[AntoineSebert]

Try cargo xtest --target x86_64-blog_os.json.

I have the same problem but couldn't figure out why the file isn't automatically found.

[phil-opp]

@AntoineSebert Do you have a build.target key defined in your .cargo/config file?

@Beidah Sounds like forgot a #![no_std] attribute (perhaps the conditional attribute in your lib.rs?). Or you accidentally use a dependency that uses std.

[AntoineSebert]

@phil-opp Yes it's there. The problem seems to have disappread today, and anyway it's not a big deal.

[AntoineSebert]

The recent improvements in the test framework now produce text outputs that are not colored in green, thus making the test result less visible within the terminal.
Is there a way to specify a color for the text when calling print/println macros ?

[phil-opp]

Yes, there is! You can use ANSI escape codes for coloring. For example, you can create a type to print something in green:

use core::fmt;

struct Green(&'static str);

impl fmt::Display for Green {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { 
        write!(f, "\x1B[32m")?; // prefix code
        write!(f, "{}", self.0)?;
        write!(f, "\x1B[0m")?; // postfix code
        Ok(())
    }
}

Now you can do serial_println!("{}", Green("[ok]")); at the end of your test.

I opened #603 for adding this to the post.

[bytesnail]

In the process of adding tests, I encountered some strange errors. In this test, I simply created a writer, but failed, and judging from the error message, it seems that it did not execute any tests at all, because I did not see the information printed by test_runner or panic_handler on the console.

lws@lsw:/document/project/flandre-os/FlandreOS$ cargo xtest test_default_writer
   Compiling flandre_os v0.0.1 (/document/project/flandre-os/FlandreOS)
    Finished dev [unoptimized + debuginfo] target(s) in 0.33s
     Running target/x86_64-flandre_os/debug/deps/flandre_os-d120248f92b70111
Building bootloader
   Compiling bootloader v0.6.0 (/work/tool/rust/cargo/registry/src/mirrors.ustc.edu.cn-61ef6e0cd06fb9b8/bootloader-0.6.0)
    Finished release [optimized + debuginfo] target(s) in 0.72s
Running: `qemu-system-x86_64 -drive format=raw,file=/document/project/flandre-os/FlandreOS/target/x86_64-flandre_os/debug/deps/bootimage-flandre_os-d120248f92b70111.bin -device isa-debug-exit,iobase=0xf4,iosize=0x04 -serial stdio -display none test_default_writer`
qemu-system-x86_64: -display none: drive with bus=0, unit=0 (index=0) exists
error: test failed, to rerun pass '--lib'

[bytesnail]

I did all kinds of printing tests and the printing function seemed to work normally, but when I tried to add some tests to ensure that these functions would not be damaged in future modifications, I got the above errors.

[bjorn3]

I think passing a test name to cargo xtest doesnt work. Try running just cargo xtest.

[phil-opp]

I think passing a test name to cargo xtest doesnt work. Try running just cargo xtest.

Yes, as you see from the "Running: …" output, the test_default_writer is directly passed as an argument to QEMU, which does not understand it and exits with an error. Passing the name of a single test is a feature of the default test runner and not available in our bare-metal environment because our kernel does not get any arguments passed when it's started.

What you can do is to run the tests of the library component through cargo xtest --lib and the tests of the binary through cargo xtest --bin blog_os. You can also run an individual integration test through cargo xtest --test test_name.