[webkit-dev] Does NRWT let you indicate that a test should fail with a particular failure diff?

Darin Adler darin at apple.com
Fri Jul 1 15:04:43 PDT 2011

On Jul 1, 2011, at 2:54 PM, Dirk Pranke wrote:

> Does that apply to -expected.txt files in the base directories, or just platform-specific exceptions?

Base directories.

Expected files contain output reflecting the behavior of WebKit at the time the test was checked in. The expected result when we re-run a test. Many expected files contain text that says “FAIL” in them. The fact that these expected results are not successes, but rather expected failures does not seem to me to be a subtle point, but one of the basic things about how these tests are set up.

> I wonder how it is that I've been working (admittedly, mostly on tooling) in WebKit for more that two years and this is the first I'm hearing about this.

I’m guessing it’s because you have been working on Chrome.

The Chrome project came up with a different system for testing layered on top of the original layout test machinery based on different concepts. I don’t think anyone ever discussed that system with me; I was the one who created the original layout test system, to help Dave Hyatt originally, and then later the rest of the team started using it.

> Are there reasons we [are] doing things this way[?]

Sure. The idea of the layout test framework is to check if the code is still behaving as it did when the test was created and last run; we want to detect any changes in behavior that are not expected. When there are expected changes in behavior, we change the contents of the expected results files.

It seems possibly helpful to augment the test system with editorial comments about which tests show bugs that we’d want to fix. But I wouldn’t want to stop running all regression tests where the output reflects the effects of a bug or missing feature.

    -- Darin

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