view tests/test-chg.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

#require chg

  $ cp $HGRCPATH $HGRCPATH.orig

init repo

  $ chg init foo
  $ cd foo

ill-formed config

  $ chg status
  $ echo '=brokenconfig' >> $HGRCPATH
  $ chg status
  hg: parse error at * (glob)
  [255]

  $ cp $HGRCPATH.orig $HGRCPATH

long socket path

  $ sockpath=$TESTTMP/this/path/should/be/longer/than/one-hundred-and-seven/characters/where/107/is/the/typical/size/limit/of/unix-domain-socket
  $ mkdir -p $sockpath
  $ bakchgsockname=$CHGSOCKNAME
  $ CHGSOCKNAME=$sockpath/server
  $ export CHGSOCKNAME
  $ chg root
  $TESTTMP/foo
  $ rm -rf $sockpath
  $ CHGSOCKNAME=$bakchgsockname
  $ export CHGSOCKNAME

  $ cd ..

editor
------

  $ cat >> pushbuffer.py <<EOF
  > def reposetup(ui, repo):
  >     repo.ui.pushbuffer(subproc=True)
  > EOF

  $ chg init editor
  $ cd editor

by default, system() should be redirected to the client:

  $ touch foo
  $ CHGDEBUG= HGEDITOR=cat chg ci -Am channeled --edit 2>&1 \
  > | egrep "HG:|run 'cat"
  chg: debug: * run 'cat "*"' at '$TESTTMP/editor' (glob)
  HG: Enter commit message.  Lines beginning with 'HG:' are removed.
  HG: Leave message empty to abort commit.
  HG: --
  HG: user: test
  HG: branch 'default'
  HG: added foo

but no redirection should be made if output is captured:

  $ touch bar
  $ CHGDEBUG= HGEDITOR=cat chg ci -Am bufferred --edit \
  > --config extensions.pushbuffer="$TESTTMP/pushbuffer.py" 2>&1 \
  > | egrep "HG:|run 'cat"
  [1]

check that commit commands succeeded:

  $ hg log -T '{rev}:{desc}\n'
  1:bufferred
  0:channeled

  $ cd ..

pager
-----

  $ cat >> fakepager.py <<EOF
  > import sys
  > for line in sys.stdin:
  >     sys.stdout.write('paged! %r\n' % line)
  > EOF

enable pager extension globally, but spawns the master server with no tty:

  $ chg init pager
  $ cd pager
  $ cat >> $HGRCPATH <<EOF
  > [extensions]
  > pager =
  > [pager]
  > pager = "$PYTHON" $TESTTMP/fakepager.py
  > EOF
  $ chg version > /dev/null
  $ touch foo
  $ chg ci -qAm foo

pager should be enabled if the attached client has a tty:

  $ chg log -l1 -q --config ui.formatted=True
  paged! '0:1f7b0de80e11\n'
  $ chg log -l1 -q --config ui.formatted=False
  0:1f7b0de80e11

chg waits for pager if runcommand raises

  $ cat > $TESTTMP/crash.py <<EOF
  > from mercurial import registrar
  > cmdtable = {}
  > command = registrar.command(cmdtable)
  > @command(b'crash')
  > def pagercrash(ui, repo, *pats, **opts):
  >     ui.write('going to crash\n')
  >     raise Exception('.')
  > EOF

  $ cat > $TESTTMP/fakepager.py <<EOF
  > from __future__ import absolute_import
  > import sys
  > import time
  > for line in iter(sys.stdin.readline, ''):
  >     if 'crash' in line: # only interested in lines containing 'crash'
  >         # if chg exits when pager is sleeping (incorrectly), the output
  >         # will be captured by the next test case
  >         time.sleep(1)
  >         sys.stdout.write('crash-pager: %s' % line)
  > EOF

  $ cat >> .hg/hgrc <<EOF
  > [extensions]
  > crash = $TESTTMP/crash.py
  > EOF

  $ chg crash --pager=on --config ui.formatted=True 2>/dev/null
  crash-pager: going to crash
  [255]

  $ cd ..

server lifecycle
----------------

chg server should be restarted on code change, and old server will shut down
automatically. In this test, we use the following time parameters:

 - "sleep 1" to make mtime different
 - "sleep 2" to notice mtime change (polling interval is 1 sec)

set up repository with an extension:

  $ chg init extreload
  $ cd extreload
  $ touch dummyext.py
  $ cat <<EOF >> .hg/hgrc
  > [extensions]
  > dummyext = dummyext.py
  > EOF

isolate socket directory for stable result:

  $ OLDCHGSOCKNAME=$CHGSOCKNAME
  $ mkdir chgsock
  $ CHGSOCKNAME=`pwd`/chgsock/server

warm up server:

  $ CHGDEBUG= chg log 2>&1 | egrep 'instruction|start'
  chg: debug: * start cmdserver at $TESTTMP/extreload/chgsock/server.* (glob)

new server should be started if extension modified:

  $ sleep 1
  $ touch dummyext.py
  $ CHGDEBUG= chg log 2>&1 | egrep 'instruction|start'
  chg: debug: * instruction: unlink $TESTTMP/extreload/chgsock/server-* (glob)
  chg: debug: * instruction: reconnect (glob)
  chg: debug: * start cmdserver at $TESTTMP/extreload/chgsock/server.* (glob)

old server will shut down, while new server should still be reachable:

  $ sleep 2
  $ CHGDEBUG= chg log 2>&1 | (egrep 'instruction|start' || true)

socket file should never be unlinked by old server:
(simulates unowned socket by updating mtime, which makes sure server exits
at polling cycle)

  $ ls chgsock/server-*
  chgsock/server-* (glob)
  $ touch chgsock/server-*
  $ sleep 2
  $ ls chgsock/server-*
  chgsock/server-* (glob)

since no server is reachable from socket file, new server should be started:
(this test makes sure that old server shut down automatically)

  $ CHGDEBUG= chg log 2>&1 | egrep 'instruction|start'
  chg: debug: * start cmdserver at $TESTTMP/extreload/chgsock/server.* (glob)

shut down servers and restore environment:

  $ rm -R chgsock
  $ CHGSOCKNAME=$OLDCHGSOCKNAME
  $ cd ..