testing: allow Hypothesis to enable extensions
This adds support for testing extensions, including both tests
that extensions don't change behaviour and test for specific
commands.
We use the precondition system to determine what commands are
available to us. If we never use any commands enabled by an
extension then that extension is *skippable* and should not
have changed the behaviour of the test. We thus rerun the test
with an environment variable which is designed to turn off the
extension.
$ hg init
$ echo a > a
$ hg ci -Ama
adding a
$ hg an a
0: a
$ hg --config ui.strict=False an a
0: a
$ echo "[ui]" >> $HGRCPATH
$ echo "strict=True" >> $HGRCPATH
$ hg an a
hg: unknown command 'an'
Mercurial Distributed SCM
basic commands:
add add the specified files on the next commit
annotate show changeset information by line for each file
clone make a copy of an existing repository
commit commit the specified files or all outstanding changes
diff diff repository (or selected files)
export dump the header and diffs for one or more changesets
forget forget the specified files on the next commit
init create a new repository in the given directory
log show revision history of entire repository or files
merge merge another revision into working directory
pull pull changes from the specified source
push push changes to the specified destination
remove remove the specified files on the next commit
serve start stand-alone webserver
status show changed files in the working directory
summary summarize working directory state
update update working directory (or switch revisions)
(use "hg help" for the full list of commands or "hg -v" for details)
[255]
$ hg annotate a
0: a
should succeed - up is an alias, not an abbreviation
$ hg up
0 files updated, 0 files merged, 0 files removed, 0 files unresolved