view tests/test-convert-cvsnt-mergepoints.t @ 39788: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 cvs

  $ filterpath()
  > {
  >     eval "$@" | sed "s:$CVSROOT:*REPO*:g"
  > }
  $ cvscall()
  > {
  >     cvs -f "$@"
  > }

output of 'cvs ci' varies unpredictably, so discard most of it
-- just keep the part that matters

  $ cvsci()
  > {
  >     cvs -f ci -f "$@" > /dev/null
  > }
  $ hgcat()
  > {
  >     hg --cwd src-hg cat -r tip "$1"
  > }
  $ echo "[extensions]" >> $HGRCPATH
  $ echo "convert = " >> $HGRCPATH

create cvs repository

  $ mkdir cvsmaster
  $ cd cvsmaster
  $ CVSROOT=`pwd`
  $ export CVSROOT
  $ CVS_OPTIONS=-f
  $ export CVS_OPTIONS
  $ cd ..
  $ rmdir cvsmaster
  $ filterpath cvscall -Q -d "$CVSROOT" init

checkout #1: add foo.txt

  $ cvscall -Q checkout -d cvsworktmp .
  $ cd cvsworktmp
  $ mkdir foo
  $ cvscall -Q add foo
  $ cd foo
  $ echo foo > foo.txt
  $ cvscall -Q add foo.txt
  $ cvsci -m "add foo.txt" foo.txt
  $ cd ../..
  $ rm -rf cvsworktmp

checkout #2: create MYBRANCH1 and modify foo.txt on it

  $ cvscall -Q checkout -d cvswork foo
  $ cd cvswork
  $ cvscall -q rtag -b -R MYBRANCH1 foo
  $ cvscall -Q update -P -r MYBRANCH1
  $ echo bar > foo.txt
  $ cvsci -m "bar" foo.txt
  $ echo baz > foo.txt
  $ cvsci -m "baz" foo.txt

create MYBRANCH1_2 and modify foo.txt some more

  $ cvscall -q rtag -b -R -r MYBRANCH1 MYBRANCH1_2 foo
  $ cvscall -Q update -P -r MYBRANCH1_2
  $ echo bazzie > foo.txt
  $ cvsci -m "bazzie" foo.txt

create MYBRANCH1_1 and modify foo.txt yet again

  $ cvscall -q rtag -b -R MYBRANCH1_1 foo
  $ cvscall -Q update -P -r MYBRANCH1_1
  $ echo quux > foo.txt
  $ cvsci -m "quux" foo.txt

merge MYBRANCH1 to MYBRANCH1_1

  $ filterpath cvscall -Q update -P -jMYBRANCH1
  rcsmerge: warning: conflicts during merge
  RCS file: *REPO*/foo/foo.txt,v
  retrieving revision 1.1
  retrieving revision 1.1.2.2
  Merging differences between 1.1 and 1.1.2.2 into foo.txt

carefully placed sleep to dodge cvs bug (optimization?) where it
sometimes ignores a "commit" command if it comes too fast (the -f
option in cvsci seems to work for all the other commits in this
script)

  $ sleep 1
  $ echo xyzzy > foo.txt
  $ cvsci -m "merge1+clobber" foo.txt

#if unix-permissions

return to trunk and merge MYBRANCH1_2

  $ cvscall -Q update -P -A
  $ filterpath cvscall -Q update -P -jMYBRANCH1_2
  RCS file: *REPO*/foo/foo.txt,v
  retrieving revision 1.1
  retrieving revision 1.1.2.2.2.1
  Merging differences between 1.1 and 1.1.2.2.2.1 into foo.txt
  $ cvsci -m "merge2" foo.txt
  $ REALCVS=`which cvs`
  $ echo "for x in \$*; do if [ \"\$x\" = \"rlog\" ]; then echo \"RCS file: $CVSROOT/foo/foo.txt,v\"; cat \"$TESTDIR/test-convert-cvsnt-mergepoints.rlog\"; exit 0; fi; done; $REALCVS \$*" > ../cvs
  $ chmod +x ../cvs
  $ PATH=..:${PATH} hg debugcvsps --parents foo
  collecting CVS rlog
  7 log entries
  creating changesets
  7 changeset entries
  ---------------------
  PatchSet 1 
  Date: * (glob)
  Author: user
  Branch: HEAD
  Tag: (none) 
  Branchpoints: MYBRANCH1, MYBRANCH1_1 
  Log:
  foo.txt
  
  Members: 
  	foo.txt:INITIAL->1.1 
  
  ---------------------
  PatchSet 2 
  Date: * (glob)
  Author: user
  Branch: MYBRANCH1
  Tag: (none) 
  Parent: 1
  Log:
  bar
  
  Members: 
  	foo.txt:1.1->1.1.2.1 
  
  ---------------------
  PatchSet 3 
  Date: * (glob)
  Author: user
  Branch: MYBRANCH1
  Tag: (none) 
  Branchpoints: MYBRANCH1_2 
  Parent: 2
  Log:
  baz
  
  Members: 
  	foo.txt:1.1.2.1->1.1.2.2 
  
  ---------------------
  PatchSet 4 
  Date: * (glob)
  Author: user
  Branch: MYBRANCH1_1
  Tag: (none) 
  Parent: 1
  Log:
  quux
  
  Members: 
  	foo.txt:1.1->1.1.4.1 
  
  ---------------------
  PatchSet 5 
  Date: * (glob)
  Author: user
  Branch: MYBRANCH1_2
  Tag: (none) 
  Parent: 3
  Log:
  bazzie
  
  Members: 
  	foo.txt:1.1.2.2->1.1.2.2.2.1 
  
  ---------------------
  PatchSet 6 
  Date: * (glob)
  Author: user
  Branch: HEAD
  Tag: (none) 
  Parents: 1,5
  Log:
  merge
  
  Members: 
  	foo.txt:1.1->1.2 
  
  ---------------------
  PatchSet 7 
  Date: * (glob)
  Author: user
  Branch: MYBRANCH1_1
  Tag: (none) 
  Parents: 4,3
  Log:
  merge
  
  Members: 
  	foo.txt:1.1.4.1->1.1.4.2 
  
#endif

  $ cd ..