tests/test-serve.t

debugcommands: introduce actions to perform deterministic reads

"readavailable" is useful as a debugging device to see what data is
available on a pipe. But the mechanism isn't deterministic because
what's available on a pipe is highly conditional on timing, system
load, OS behavior, etc. This makes it not suitable for tests.

We introduce "ereadline," "read," and "eread" for performing
deterministic I/O operations (at least on blocking file descriptors).

We stop short of converting existing consumers of "readavailable"
in tests because we're working out race conditions and deadlocks
on Windows. But the goal is to eventually move tests away from
"readavailable" to these new APIs.

Differential Revision: https://phab.mercurial-scm.org/D2720

#require serve

  $ hgserve()
  > {
  >    hg serve -a localhost -d --pid-file=hg.pid -E errors.log -v $@ \
  >        | sed -e "s/:$HGPORT1\\([^0-9]\\)/:HGPORT1\1/g" \
  >              -e "s/:$HGPORT2\\([^0-9]\\)/:HGPORT2\1/g" \
  >              -e 's/http:\/\/[^/]*\//http:\/\/localhost\//'
  >    cat hg.pid >> "$DAEMON_PIDS"
  >    echo % errors
  >    cat errors.log
  >    killdaemons.py hg.pid
  > }

  $ hg init test
  $ cd test
  $ echo '[web]' > .hg/hgrc
  $ echo 'accesslog = access.log' >> .hg/hgrc
  $ echo "port = $HGPORT1" >> .hg/hgrc

Without -v

  $ hg serve -a localhost -p $HGPORT -d --pid-file=hg.pid -E errors.log
  $ cat hg.pid >> "$DAEMON_PIDS"
  $ if [ -f access.log ]; then
  >     echo 'access log created - .hg/hgrc respected'
  > fi
  access log created - .hg/hgrc respected

errors

  $ cat errors.log

With -v

  $ hgserve
  listening at http://localhost/ (bound to *$LOCALIP*:HGPORT1) (glob) (?)
  % errors

With -v and -p HGPORT2

  $ hgserve -p "$HGPORT2"
  listening at http://localhost/ (bound to *$LOCALIP*:HGPORT2) (glob) (?)
  % errors

With -v and -p daytime (should fail because low port)

#if no-root no-windows
  $ KILLQUIETLY=Y
  $ hgserve -p daytime
  abort: cannot start server at 'localhost:13': Permission denied
  abort: child process failed to start
  % errors
  $ KILLQUIETLY=N
#endif

With --prefix foo

  $ hgserve --prefix foo
  listening at http://localhost/foo/ (bound to *$LOCALIP*:HGPORT1) (glob) (?)
  % errors

With --prefix /foo

  $ hgserve --prefix /foo
  listening at http://localhost/foo/ (bound to *$LOCALIP*:HGPORT1) (glob) (?)
  % errors

With --prefix foo/

  $ hgserve --prefix foo/
  listening at http://localhost/foo/ (bound to *$LOCALIP*:HGPORT1) (glob) (?)
  % errors

With --prefix /foo/

  $ hgserve --prefix /foo/
  listening at http://localhost/foo/ (bound to *$LOCALIP*:HGPORT1) (glob) (?)
  % errors

  $ cd ..