How to set logging level while running cargo test?

Question

I need to change the logging level while running the unit tests for a library. I am using the cargo test command to run the tests.

Is there any way to specify the logging level on the command line? From the documentation of the log crate, it seems like I need to define an environment variable separately. That may not be convenient as I would like to change the logging level to debug only when a test case fails.

score 13 · Accepted Answer · edited Nov 05 '17 at 16:55

13

Cargo doesn't support this yet, but you are welcome to file an issue for it.

RUST_LOG=debug cargo test should work, you can set environment variables for single commands instead of setting them for the current environment.

More info on the RUST_LOG env variable here.

edited Nov 05 '17 at 16:55

creativcoder

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answered Nov 07 '14 at 19:16

Manishearth

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Actually this style doesn't work in Windows, since working with environment variables in Windows is slightly less straightforward. – Shailesh Kumar Nov 08 '14 at 08:15
@ShaileshKumar `SET RUST_LOG=debug; cargo test; SET RUST_LOG=` – Manishearth Nov 08 '14 at 08:18
Tried that. Have to run each command separately rather than in one line. – Shailesh Kumar Nov 08 '14 at 08:23
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Issue filed https://github.com/rust-lang/cargo/issues/818 – Shailesh Kumar Nov 08 '14 at 08:23
See my answer [here](http://stackoverflow.com/questions/30177845/how-to-initialize-the-logger-for-integration-tests/41335165#41335165) for a quick and dirty solution. – Drazen Urch Dec 26 '16 at 18:51

How to set logging level while running cargo test?

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