Fix coveralls integration

[johanneskoester]

This PR provides a fix for the broken coveralls integration.

1. It also looks in stderr for the output of cargo. Otherwise, the test binary won't be found by the regex.
2. It pins kcov to a specific version, in order to avoid unexpected changes in the behavior of kcov.
3. It creates the kcov output directory before execution. Otherwise, kcov would exit with an error.

This fixes issue #58.
Note that this PR subsumes #64, #61, and #55.

[autohuonw]

Thanks for the pull request, and welcome! You should hear from @huonw (or someone else) soon.

[coveralls]

Coverage increased (+9.6%) to 88.889% when pulling 12b95ad on johanneskoester:master into af51893 on huonw:master.

[coveralls]

Coverage increased (+9.6%) to 88.889% when pulling 12b95ad on johanneskoester:master into af51893 on huonw:master.

[coveralls]

Coverage increased (+9.6%) to 88.889% when pulling 12b95ad on johanneskoester:master into af51893 on huonw:master.

[coveralls]

Coverage increased (+9.6%) to 88.889% when pulling 12b95ad on johanneskoester:master into af51893 on huonw:master.

[coveralls]

Coverage increased (+9.6%) to 88.889% when pulling 12b95ad on johanneskoester:master into af51893 on huonw:master.

[coveralls]

Coverage increased (+9.6%) to 88.889% when pulling 12b95ad on johanneskoester:master into af51893 on huonw:master.

[coveralls]

Coverage increased (+9.6%) to 88.889% when pulling 12b95ad on johanneskoester:master into af51893 on huonw:master.

[johanneskoester]

Some test cases fail, but they don't look related to my changes. In fact, they also fail with the master branch without my changes.

[SimonKagstrom]

Out of interest, what options are passed to kcov? I don't remember removing any command line option since v31, there are just a few added ones (speaking as the kcov developer). It would be great to just see the entire kcov command line from a failing run.

There are improvements and bug fixes in kcov since v31, so it would be unfortunate to be stuck with that. That said, I agree fixing a version is good - the kcov HEAD is sometimes broken for obvious reasons.

[johanneskoester]

This PR uses v33 already. It turned out that the recent changes where not the cause of the problem. It was rather a combination of changes in rust and bugs in the codebase of travis-cargo.

[gnzlbg]

Any progress on this, @huonw ?

[gnzlbg]

I've posted this on internals: https://users.rust-lang.org/t/travis-cargo-status-and-future/9621

[fabricedesre]

Is anyone trying to push that to the finish line?

[johanneskoester]

I have moved to this one: https://github.com/roblabla/cargo-travis/
It works flawlessly and is pure rust.

[fabricedesre]

Thanks @johanneskoester !

[janhohenheim]

@huonw any plans on merging this and the other PRs? Even though this repo is no longer actively maintained, it would be nice if the community made fixes found a way into the main branch.