tests: add coverage for git.changelog.headrevs(...) Differential Revision: https://phab.mercurial-scm.org/D10523

git: make changelog.tiprev() return int instead of tuple (issue6510) Differential Revision: https://phab.mercurial-scm.org/D10522

git: fix partial node matching Looks like everything is meant to be a str here. Differential Revision: https://phab.mercurial-scm.org/D10521

tests: stabilize test-git-interop.t for some versions of git Not sure why this differs on my system, but it's likely due to running 2.17.1 on Ubuntu 18.04. Differential Revision: https://phab.mercurial-scm.org/D10520

manifests: push down expected node length into the parser This strictly enforces the node length in the manifest lines according to what the repository expects. One test case moves large hash testing into the non-treemanifest part as treemanifests don't provide an interface for overriding just the node length for now. Differential Revision: https://phab.mercurial-scm.org/D10533

core: don't hard-code node length Differential Revision: https://phab.mercurial-scm.org/D10536

core: don't hard-code hex node lengths Differential Revision: https://phab.mercurial-scm.org/D10535

tests: bump default timeout to 360s A number of tests hit or almost hit the default limit even on modern hardware. While the tests are ideally split into smaller pieces, that's non-trivial work. HyperThreading and similar technologies can trigger this often, even without any other load on the machine. Differential Revision: https://phab.mercurial-scm.org/D10534

enforcesinglehead-test: add the expected node output next to the error this make it simpler to validate that the test is correct. Differential Revision: https://phab.mercurial-scm.org/D10545

revlog: code for `revlogv0` in its own module This code is mostly unused compatiblity code. Yet it take a prohiminent place in the `revlog.py` module. That module is already quite big, so we move all that code in a dedicated module. Differential Revision: https://phab.mercurial-scm.org/D10511