view tests/test-narrow-pull.t @ 39772:ae531f5e583c

testing: add interface unit tests for file storage

Our strategy for supporting alternate storage backends is to define
interfaces for everything then "code to the interface."

We already have interfaces for various primitives, including file
and manifest storage.

What we don't have is generic unit tests for those interfaces. Up
to this point we've been relying on high-level integration tests
(mainly in the form of existing .t tests) to test alternate storage
backends. And my experience with developing the "simple store" test
extension is that such testing is very tedious: it takes several
minutes to run all tests and when you find a failure, it is often
non-trivial to debug.

This commit starts to change that.

This commit introduces the mercurial.testing.storage module. It
contains testing code for storage. Currently, it defines some
unittest.TestCase classes for testing the file storage interfaces.
It also defines some factory functions that allow a caller to easily
spawn a custom TestCase "bound" to a specific file storage backend
implementation.

A new .py test has been added. It simply defines a callable to produce
filelog and transaction instances on demand and then "registers" the
various test classes so the filelog class can be tested with the
storage interface unit tests.

As part of writing the tests, I identified a couple of apparent
bugs in revlog.py and filelog.py! These are tracked with inline
TODO comments.

Writing the tests makes it more obvious where the storage interface
is lacking. For example, we raise either IndexError or
error.LookupError for missing revisions depending on whether we
use an integer revision or a node. Also, we raise error.RevlogError
in various places when we should be raising a storage-agnostic
error type.

The storage interfaces are currently far from perfect and there is much
work to be done to improve them. But at least with this commit we
finally have the start of unit tests that can be used to "qualify"
the behavior of a storage backend. And when implementing and debugging
new storage backends, we now have an obvious place to define new
tests and have obvious places to insert breakpoints to facilitate
debugging. This should be invaluable when implementing new storage
backends.

I added the mercurial.testing package because these interface
conformance tests are generic and need to be usable by all storage
backends. Having the code live in tests/ would make it difficult for
storage backends implemented in extensions to test their interface
conformance. First, it would require obtaining a copy of Mercurial's
storage test code in order to test. Second, it would make testing
against multiple Mercurial versions difficult, as you would need to
import N copies of the storage testing code in order to achieve test
coverage. By making the test code part of the Mercurial distribution
itself, extensions can `import mercurial.testing.*` to access and run
the test code. The test will run against whatever Mercurial version
is active.

FWIW I've always wanted to move parts of run-tests.py into the
mercurial.* package to make the testing story simpler (e.g. imagine an
`hg debugruntests` command that could invoke the test harness). While I
have no plans to do that in the near future, establishing the
mercurial.testing package does provide a natural home for that code
should someone do this in the future.

Differential Revision: https://phab.mercurial-scm.org/D4650

  $ . "$TESTDIR/narrow-library.sh"

  $ hg init master
  $ cd master
  $ cat >> .hg/hgrc <<EOF
  > [narrow]
  > serveellipses=True
  > EOF
  $ for x in `$TESTDIR/seq.py 10`
  > do
  >   echo $x > "f$x"
  >   hg add "f$x"
  >   hg commit -m "Commit f$x"
  > done
  $ cd ..

narrow clone a couple files, f2 and f8

  $ hg clone --narrow ssh://user@dummy/master narrow --include "f2" --include "f8"
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 5 changesets with 2 changes to 2 files
  new changesets *:* (glob)
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd narrow
  $ ls
  f2
  f8
  $ cat f2 f8
  2
  8

  $ cd ..

change every upstream file twice

  $ cd master
  $ for x in `$TESTDIR/seq.py 10`
  > do
  >   echo "update#1 $x" >> "f$x"
  >   hg commit -m "Update#1 to f$x" "f$x"
  > done
  $ for x in `$TESTDIR/seq.py 10`
  > do
  >   echo "update#2 $x" >> "f$x"
  >   hg commit -m "Update#2 to f$x" "f$x"
  > done
  $ cd ..

look for incoming changes

  $ cd narrow
  $ hg incoming --limit 3
  comparing with ssh://user@dummy/master
  searching for changes
  changeset:   5:ddc055582556
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     Update#1 to f1
  
  changeset:   6:f66eb5ad621d
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     Update#1 to f2
  
  changeset:   7:c42ecff04e99
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     Update#1 to f3
  

Interrupting the pull is safe
  $ hg --config hooks.pretxnchangegroup.bad=false pull -q
  transaction abort!
  rollback completed
  abort: pretxnchangegroup.bad hook exited with status 1
  [255]
  $ hg id
  223311e70a6f tip

pull new changes down to the narrow clone. Should get 8 new changesets: 4
relevant to the narrow spec, and 4 ellipsis nodes gluing them all together.

  $ hg pull
  pulling from ssh://user@dummy/master
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 9 changesets with 4 changes to 2 files
  new changesets *:* (glob)
  (run 'hg update' to get a working copy)
  $ hg log -T '{rev}: {desc}\n'
  13: Update#2 to f10
  12: Update#2 to f8
  11: Update#2 to f7
  10: Update#2 to f2
  9: Update#2 to f1
  8: Update#1 to f8
  7: Update#1 to f7
  6: Update#1 to f2
  5: Update#1 to f1
  4: Commit f10
  3: Commit f8
  2: Commit f7
  1: Commit f2
  0: Commit f1
  $ hg update tip
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved

add a change and push it

  $ echo "update#3 2" >> f2
  $ hg commit -m "Update#3 to f2" f2
  $ hg log f2 -T '{rev}: {desc}\n'
  14: Update#3 to f2
  10: Update#2 to f2
  6: Update#1 to f2
  1: Commit f2
  $ hg push
  pushing to ssh://user@dummy/master
  searching for changes
  remote: adding changesets
  remote: adding manifests
  remote: adding file changes
  remote: added 1 changesets with 1 changes to 1 files
  $ cd ..

  $ cd master
  $ hg log f2 -T '{rev}: {desc}\n'
  30: Update#3 to f2
  21: Update#2 to f2
  11: Update#1 to f2
  1: Commit f2
  $ hg log -l 3 -T '{rev}: {desc}\n'
  30: Update#3 to f2
  29: Update#2 to f10
  28: Update#2 to f9

Can pull into repo with a single commit

  $ cd ..
  $ hg clone -q --narrow ssh://user@dummy/master narrow2 --include "f1" -r 0
  $ cd narrow2
  $ hg pull -q -r 1
  transaction abort!
  rollback completed
  abort: pull failed on remote
  [255]

Can use 'hg share':
  $ cat >> $HGRCPATH <<EOF
  > [extensions]
  > share=
  > EOF

  $ cd ..
  $ hg share narrow2 narrow2-share
  updating working directory
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd narrow2-share
  $ hg status

We should also be able to unshare without breaking everything:
  $ hg unshare
  $ hg verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  checked 1 changesets with 1 changes to 1 files