tests: divorce blackbox test from test-dispatch.py

I used test-dispatch.py to demonstrate what would happen if
a log file changed from being readonly to writable, by
having it replace a directory (proxy for readonly/not-writable)
with a log file in between transactions of a running python
process (proxy for Mercurial).

This commit makes it easier for people to follow what the test
is doing, by creating a real file that people can read.

tests/blackbox-readonly-dispatch.py

@@ -1,35 +1,36 b''
 from __future__ import absolute_import, print_function
 import os
 from mercurial import (
     dispatch,
 )
 
 def testdispatch(cmd):
     """Simple wrapper around dispatch.dispatch()
 
     Prints command and result value, but does not handle quoting.
     """
     print("running: %s" % (cmd,))
     req = dispatch.request(cmd.split())
     result = dispatch.dispatch(req)
     print("result: %r" % (result,))
 
-testdispatch("init test1")
-os.chdir('test1')
-
 # create file 'foo', add and commit
 f = open('foo', 'wb')
 f.write('foo\n')
 f.close()
 testdispatch("add foo")
 testdispatch("commit -m commit1 -d 2000-01-01 foo")
 
 # append to file 'foo' and commit
 f = open('foo', 'ab')
 f.write('bar\n')
 f.close()
+# remove blackbox.log directory (proxy for readonly log file)
+os.rmdir(".hg/blackbox.log")
+# replace it with the real blackbox.log file
+os.rename(".hg/blackbox.log-", ".hg/blackbox.log")
 testdispatch("commit -m commit2 -d 2000-01-02 foo")
 
 # check 88803a69b24 (fancyopts modified command table)
 testdispatch("log -r 0")
 testdispatch("log -r tip")

tests/test-blackbox.t

@@ -1,195 +1,195 b''
 setup
   $ cat >> $HGRCPATH <<EOF
   > [extensions]
   > blackbox=
   > mock=$TESTDIR/mockblackbox.py
   > mq=
   > EOF
   $ hg init blackboxtest
   $ cd blackboxtest
 
 command, exit codes, and duration
 
   $ echo a > a
   $ hg add a
   $ hg blackbox --config blackbox.dirty=True
   1970/01/01 00:00:00 bob @0000000000000000000000000000000000000000 (5000)> add a
   1970/01/01 00:00:00 bob @0000000000000000000000000000000000000000 (5000)> add a exited 0 after * seconds (glob)
   1970/01/01 00:00:00 bob @0000000000000000000000000000000000000000+ (5000)> blackbox
 
 incoming change tracking
 
 create two heads to verify that we only see one change in the log later
   $ hg commit -ma
   $ hg up null
   0 files updated, 0 files merged, 1 files removed, 0 files unresolved
   $ echo b > b
   $ hg commit -Amb
   adding b
   created new head
 
 clone, commit, pull
   $ hg clone . ../blackboxtest2
   updating to branch default
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ echo c > c
   $ hg commit -Amc
   adding c
   $ cd ../blackboxtest2
   $ hg pull
   pulling from $TESTTMP/blackboxtest (glob)
   searching for changes
   adding changesets
   adding manifests
   adding file changes
   added 1 changesets with 1 changes to 1 files
   (run 'hg update' to get a working copy)
   $ hg blackbox -l 6
   1970/01/01 00:00:00 bob @6563da9dcf87b1949716e38ff3e3dfaa3198eb06 (5000)> pull
   1970/01/01 00:00:00 bob @6563da9dcf87b1949716e38ff3e3dfaa3198eb06 (5000)> updated served branch cache in * seconds (glob)
   1970/01/01 00:00:00 bob @6563da9dcf87b1949716e38ff3e3dfaa3198eb06 (5000)> wrote served branch cache with 1 labels and 2 nodes
   1970/01/01 00:00:00 bob @6563da9dcf87b1949716e38ff3e3dfaa3198eb06 (5000)> 1 incoming changes - new heads: d02f48003e62
   1970/01/01 00:00:00 bob @6563da9dcf87b1949716e38ff3e3dfaa3198eb06 (5000)> pull exited 0 after * seconds (glob)
   1970/01/01 00:00:00 bob @6563da9dcf87b1949716e38ff3e3dfaa3198eb06 (5000)> blackbox -l 6
 
 we must not cause a failure if we cannot write to the log
 
   $ hg rollback
   repository tip rolled back to revision 1 (undo pull)
 
   $ mv .hg/blackbox.log .hg/blackbox.log-
   $ mkdir .hg/blackbox.log
   $ hg --debug incoming
   warning: cannot write to blackbox.log: * (glob)
   comparing with $TESTTMP/blackboxtest (glob)
   query 1; heads
   searching for changes
   all local heads known remotely
   changeset:   2:d02f48003e62c24e2659d97d30f2a83abe5d5d51
   tag:         tip
   phase:       draft
   parent:      1:6563da9dcf87b1949716e38ff3e3dfaa3198eb06
   parent:      -1:0000000000000000000000000000000000000000
   manifest:    2:ab9d46b053ebf45b7996f2922b9893ff4b63d892
   user:        test
   date:        Thu Jan 01 00:00:00 1970 +0000
   files+:      c
   extra:       branch=default
   description:
   c
   
   
   $ hg pull
   pulling from $TESTTMP/blackboxtest (glob)
   searching for changes
   adding changesets
   adding manifests
   adding file changes
   added 1 changesets with 1 changes to 1 files
   (run 'hg update' to get a working copy)
 
 a failure reading from the log is fatal
 
   $ hg blackbox -l 3
   abort: *$TESTTMP/blackboxtest2/.hg/blackbox.log* (glob)
   [255]
 
   $ rmdir .hg/blackbox.log
   $ mv .hg/blackbox.log- .hg/blackbox.log
 
 backup bundles get logged
 
   $ touch d
   $ hg commit -Amd
   adding d
   created new head
   $ hg strip tip
   0 files updated, 0 files merged, 1 files removed, 0 files unresolved
   saved backup bundle to $TESTTMP/blackboxtest2/.hg/strip-backup/*-backup.hg (glob)
   $ hg blackbox -l 6
   1970/01/01 00:00:00 bob @73f6ee326b27d820b0472f1a825e3a50f3dc489b (5000)> strip tip
   1970/01/01 00:00:00 bob @6563da9dcf87b1949716e38ff3e3dfaa3198eb06 (5000)> saved backup bundle to $TESTTMP/blackboxtest2/.hg/strip-backup/73f6ee326b27-7612e004-backup.hg
   1970/01/01 00:00:00 bob @6563da9dcf87b1949716e38ff3e3dfaa3198eb06 (5000)> updated base branch cache in * seconds (glob)
   1970/01/01 00:00:00 bob @6563da9dcf87b1949716e38ff3e3dfaa3198eb06 (5000)> wrote base branch cache with 1 labels and 2 nodes
   1970/01/01 00:00:00 bob @6563da9dcf87b1949716e38ff3e3dfaa3198eb06 (5000)> strip tip exited 0 after * seconds (glob)
   1970/01/01 00:00:00 bob @6563da9dcf87b1949716e38ff3e3dfaa3198eb06 (5000)> blackbox -l 6
 
 extension and python hooks - use the eol extension for a pythonhook
 
   $ echo '[extensions]' >> .hg/hgrc
   $ echo 'eol=' >> .hg/hgrc
   $ echo '[hooks]' >> .hg/hgrc
   $ echo 'update = echo hooked' >> .hg/hgrc
   $ hg update
   hooked
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   1 other heads for branch "default"
   $ hg blackbox -l 6
   1970/01/01 00:00:00 bob @6563da9dcf87b1949716e38ff3e3dfaa3198eb06 (5000)> update
   1970/01/01 00:00:00 bob @6563da9dcf87b1949716e38ff3e3dfaa3198eb06 (5000)> writing .hg/cache/tags2-visible with 0 tags
   1970/01/01 00:00:00 bob @6563da9dcf87b1949716e38ff3e3dfaa3198eb06 (5000)> pythonhook-preupdate: hgext.eol.preupdate finished in * seconds (glob)
   1970/01/01 00:00:00 bob @d02f48003e62c24e2659d97d30f2a83abe5d5d51 (5000)> exthook-update: echo hooked finished in * seconds (glob)
   1970/01/01 00:00:00 bob @d02f48003e62c24e2659d97d30f2a83abe5d5d51 (5000)> update exited 0 after * seconds (glob)
   1970/01/01 00:00:00 bob @d02f48003e62c24e2659d97d30f2a83abe5d5d51 (5000)> blackbox -l 6
 
 log rotation
 
   $ echo '[blackbox]' >> .hg/hgrc
   $ echo 'maxsize = 20 b' >> .hg/hgrc
   $ echo 'maxfiles = 3' >> .hg/hgrc
   $ hg status
   $ hg status
   $ hg status
   $ hg tip -q
   2:d02f48003e62
   $ ls .hg/blackbox.log*
   .hg/blackbox.log
   .hg/blackbox.log.1
   .hg/blackbox.log.2
   $ cd ..
 
   $ hg init blackboxtest3
   $ cd blackboxtest3
   $ hg blackbox
   1970/01/01 00:00:00 bob @0000000000000000000000000000000000000000 (5000)> blackbox
   $ mv .hg/blackbox.log .hg/blackbox.log-
   $ mkdir .hg/blackbox.log
   $ sed -e 's/\(.*test1.*\)/#\1/; s#\(.*commit2.*\)#os.rmdir(".hg/blackbox.log")\
   > os.rename(".hg/blackbox.log-", ".hg/blackbox.log")\
   > \1#' $TESTDIR/test-dispatch.py > ../test-dispatch.py
-  $ python ../test-dispatch.py
+  $ python $TESTDIR/blackbox-readonly-dispatch.py
   running: add foo
   result: 0
   running: commit -m commit1 -d 2000-01-01 foo
   result: None
   running: commit -m commit2 -d 2000-01-02 foo
   result: None
   running: log -r 0
   changeset:   0:0e4634943879
   user:        test
   date:        Sat Jan 01 00:00:00 2000 +0000
   summary:     commit1
   
   result: None
   running: log -r tip
   changeset:   1:45589e459b2e
   tag:         tip
   user:        test
   date:        Sun Jan 02 00:00:00 2000 +0000
   summary:     commit2
   
   result: None
   $ hg blackbox
   1970/01/01 00:00:00 bob @0e46349438790c460c5c9f7546bfcd39b267bbd2 (5000)> commit -m commit2 -d 2000-01-02 foo
   1970/01/01 00:00:00 bob @0e46349438790c460c5c9f7546bfcd39b267bbd2 (5000)> updated served branch cache in * seconds (glob)
   1970/01/01 00:00:00 bob @0e46349438790c460c5c9f7546bfcd39b267bbd2 (5000)> wrote served branch cache with 1 labels and 1 nodes
   1970/01/01 00:00:00 bob @45589e459b2edfbf3dbde7e01f611d2c1e7453d7 (5000)> commit -m commit2 -d 2000-01-02 foo exited 0 after * seconds (glob)
   1970/01/01 00:00:00 bob @45589e459b2edfbf3dbde7e01f611d2c1e7453d7 (5000)> log -r 0
   1970/01/01 00:00:00 bob @45589e459b2edfbf3dbde7e01f611d2c1e7453d7 (5000)> writing .hg/cache/tags2-visible with 0 tags
   1970/01/01 00:00:00 bob @45589e459b2edfbf3dbde7e01f611d2c1e7453d7 (5000)> log -r 0 exited 0 after * seconds (glob)
   1970/01/01 00:00:00 bob @45589e459b2edfbf3dbde7e01f611d2c1e7453d7 (5000)> log -r tip
   1970/01/01 00:00:00 bob @45589e459b2edfbf3dbde7e01f611d2c1e7453d7 (5000)> log -r tip exited 0 after * seconds (glob)
   1970/01/01 00:00:00 bob @45589e459b2edfbf3dbde7e01f611d2c1e7453d7 (5000)> blackbox
 
 cleanup
   $ cd ..