tests: use venv on Python 3

This test was failing in some Python 3 environments because
`$PYTHON -m virtualenv` was somehow resulting in Python 2
being used. Why, I'm not sure.

Python 3 includes virtualenv in the standard library as the
`venv` module.

This commit changes test-install.t to use `$PYTHON -m venv` on
Python 3 and `$PYTHON -m virtualenv` on Python 2 (if available).

I chose to make some test output duplicated because we can't
have nested conditionals and there is no easy way to express
ORing of hghave checks.

Differential Revision: https://phab.mercurial-scm.org/D7224

tests/test-install.t

@@ -1,280 +1,312
 hg debuginstall
   $ hg debuginstall
   checking encoding (ascii)...
   checking Python executable (*) (glob)
   checking Python version (2.*) (glob) (no-py3 !)
   checking Python version (3.*) (glob) (py3 !)
   checking Python lib (.*[Ll]ib.*)... (re)
   checking Python security support (*) (glob)
     TLS 1.2 not supported by Python install; network connections lack modern security (?)
     SNI not supported by Python install; may have connectivity issues with some servers (?)
   checking Mercurial version (*) (glob)
   checking Mercurial custom build (*) (glob)
   checking module policy (*) (glob)
   checking installed modules (*mercurial)... (glob)
   checking registered compression engines (*zlib*) (glob)
   checking available compression engines (*zlib*) (glob)
   checking available compression engines for wire protocol (*zlib*) (glob)
   checking "re2" regexp engine \((available|missing)\) (re)
   checking templates (*mercurial?templates)... (glob)
   checking default template (*mercurial?templates?map-cmdline.default) (glob)
   checking commit editor... (*) (glob)
   checking username (test)
   no problems detected
 
 hg debuginstall JSON
   $ hg debuginstall -Tjson | sed 's|\\\\|\\|g'
   [
    {
     "compengines": ["bz2", "bz2truncated", "none", "zlib"*], (glob)
     "compenginesavail": ["bz2", "bz2truncated", "none", "zlib"*], (glob)
     "compenginesserver": [*"zlib"*], (glob)
     "defaulttemplate": "*mercurial?templates?map-cmdline.default", (glob)
     "defaulttemplateerror": null,
     "defaulttemplatenotfound": "default",
     "editor": "*", (glob)
     "editornotfound": false,
     "encoding": "ascii",
     "encodingerror": null,
     "extensionserror": null, (no-pure !)
     "hgmodulepolicy": "*", (glob)
     "hgmodules": "*mercurial", (glob)
     "hgver": "*", (glob)
     "hgverextra": "*", (glob)
     "problems": 0,
     "pythonexe": "*", (glob)
     "pythonlib": "*", (glob)
     "pythonsecurity": [*], (glob)
     "pythonver": "*.*.*", (glob)
     "re2": (true|false), (re)
     "templatedirs": "*mercurial?templates", (glob)
     "username": "test",
     "usernameerror": null,
     "vinotfound": false
    }
   ]
 
 hg debuginstall with no username
   $ HGUSER= hg debuginstall
   checking encoding (ascii)...
   checking Python executable (*) (glob)
   checking Python version (2.*) (glob) (no-py3 !)
   checking Python version (3.*) (glob) (py3 !)
   checking Python lib (.*[Ll]ib.*)... (re)
   checking Python security support (*) (glob)
     TLS 1.2 not supported by Python install; network connections lack modern security (?)
     SNI not supported by Python install; may have connectivity issues with some servers (?)
   checking Mercurial version (*) (glob)
   checking Mercurial custom build (*) (glob)
   checking module policy (*) (glob)
   checking installed modules (*mercurial)... (glob)
   checking registered compression engines (*zlib*) (glob)
   checking available compression engines (*zlib*) (glob)
   checking available compression engines for wire protocol (*zlib*) (glob)
   checking "re2" regexp engine \((available|missing)\) (re)
   checking templates (*mercurial?templates)... (glob)
   checking default template (*mercurial?templates?map-cmdline.default) (glob)
   checking commit editor... (*) (glob)
   checking username...
    no username supplied
    (specify a username in your configuration file)
   1 problems detected, please check your install!
   [1]
 
 hg debuginstall with invalid encoding
   $ HGENCODING=invalidenc hg debuginstall | grep encoding
   checking encoding (invalidenc)...
    unknown encoding: invalidenc
 
 exception message in JSON
 
   $ HGENCODING=invalidenc HGUSER= hg debuginstall -Tjson | grep error
     "defaulttemplateerror": null,
     "encodingerror": "unknown encoding: invalidenc",
     "extensionserror": null, (no-pure !)
     "usernameerror": "no username supplied",
 
 path variables are expanded (~ is the same as $TESTTMP)
   $ mkdir tools
   $ touch tools/testeditor.exe
 #if execbit
   $ chmod 755 tools/testeditor.exe
 #endif
   $ HGEDITOR="~/tools/testeditor.exe" hg debuginstall
   checking encoding (ascii)...
   checking Python executable (*) (glob)
   checking Python version (2.*) (glob) (no-py3 !)
   checking Python version (3.*) (glob) (py3 !)
   checking Python lib (.*[Ll]ib.*)... (re)
   checking Python security support (*) (glob)
     TLS 1.2 not supported by Python install; network connections lack modern security (?)
     SNI not supported by Python install; may have connectivity issues with some servers (?)
   checking Mercurial version (*) (glob)
   checking Mercurial custom build (*) (glob)
   checking module policy (*) (glob)
   checking installed modules (*mercurial)... (glob)
   checking registered compression engines (*zlib*) (glob)
   checking available compression engines (*zlib*) (glob)
   checking available compression engines for wire protocol (*zlib*) (glob)
   checking "re2" regexp engine \((available|missing)\) (re)
   checking templates (*mercurial?templates)... (glob)
   checking default template (*mercurial?templates?map-cmdline.default) (glob)
   checking commit editor... ($TESTTMP/tools/testeditor.exe)
   checking username (test)
   no problems detected
 
 print out the binary post-shlexsplit in the error message when commit editor is
 not found (this is intentionally using backslashes to mimic a windows usecase).
   $ HGEDITOR="c:\foo\bar\baz.exe -y -z" hg debuginstall
   checking encoding (ascii)...
   checking Python executable (*) (glob)
   checking Python version (2.*) (glob) (no-py3 !)
   checking Python version (3.*) (glob) (py3 !)
   checking Python lib (.*[Ll]ib.*)... (re)
   checking Python security support (*) (glob)
     TLS 1.2 not supported by Python install; network connections lack modern security (?)
     SNI not supported by Python install; may have connectivity issues with some servers (?)
   checking Mercurial version (*) (glob)
   checking Mercurial custom build (*) (glob)
   checking module policy (*) (glob)
   checking installed modules (*mercurial)... (glob)
   checking registered compression engines (*zlib*) (glob)
   checking available compression engines (*zlib*) (glob)
   checking available compression engines for wire protocol (*zlib*) (glob)
   checking "re2" regexp engine \((available|missing)\) (re)
   checking templates (*mercurial?templates)... (glob)
   checking default template (*mercurial?templates?map-cmdline.default) (glob)
   checking commit editor... (c:\foo\bar\baz.exe) (windows !)
    Can't find editor 'c:\foo\bar\baz.exe' in PATH (windows !)
   checking commit editor... (c:foobarbaz.exe) (no-windows !)
    Can't find editor 'c:foobarbaz.exe' in PATH (no-windows !)
    (specify a commit editor in your configuration file)
   checking username (test)
   1 problems detected, please check your install!
   [1]
 
 debuginstall extension support
   $ hg debuginstall --config extensions.fsmonitor= --config fsmonitor.watchman_exe=false | grep atchman
   fsmonitor checking for watchman binary... (false)
    watchman binary missing or broken: warning: Watchman unavailable: watchman exited with code 1
 Verify the json works too:
   $ hg debuginstall --config extensions.fsmonitor= --config fsmonitor.watchman_exe=false -Tjson | grep atchman
     "fsmonitor-watchman": "false",
     "fsmonitor-watchman-error": "warning: Watchman unavailable: watchman exited with code 1",
 
 
 #if test-repo
   $ . "$TESTDIR/helpers-testrepo.sh"
 
   $ cat >> wixxml.py << EOF
   > import os
   > import subprocess
   > import sys
   > import xml.etree.ElementTree as ET
   > from mercurial import pycompat
   > 
   > # MSYS mangles the path if it expands $TESTDIR
   > testdir = os.environ['TESTDIR']
   > ns = {'wix' : 'http://schemas.microsoft.com/wix/2006/wi'}
   > 
   > def directory(node, relpath):
   >     '''generator of files in the xml node, rooted at relpath'''
   >     dirs = node.findall('./{%(wix)s}Directory' % ns)
   > 
   >     for d in dirs:
   >         for subfile in directory(d, relpath + d.attrib['Name'] + '/'):
   >             yield subfile
   > 
   >     files = node.findall('./{%(wix)s}Component/{%(wix)s}File' % ns)
   > 
   >     for f in files:
   >         yield pycompat.sysbytes(relpath + f.attrib['Name'])
   > 
   > def hgdirectory(relpath):
   >     '''generator of tracked files, rooted at relpath'''
   >     hgdir = "%s/../mercurial" % (testdir)
   >     args = ['hg', '--cwd', hgdir, 'files', relpath]
   >     proc = subprocess.Popen(args, stdout=subprocess.PIPE,
   >                             stderr=subprocess.PIPE)
   >     output = proc.communicate()[0]
   > 
   >     for line in output.splitlines():
   >         if os.name == 'nt':
   >             yield line.replace(pycompat.sysbytes(os.sep), b'/')
   >         else:
   >             yield line
   > 
   > tracked = [f for f in hgdirectory(sys.argv[1])]
   > 
   > xml = ET.parse("%s/../contrib/packaging/wix/%s.wxs" % (testdir, sys.argv[1]))
   > root = xml.getroot()
   > dir = root.find('.//{%(wix)s}DirectoryRef' % ns)
   > 
   > installed = [f for f in directory(dir, '')]
   > 
   > print('Not installed:')
   > for f in sorted(set(tracked) - set(installed)):
   >     print('  %s' % pycompat.sysstr(f))
   > 
   > print('Not tracked:')
   > for f in sorted(set(installed) - set(tracked)):
   >     print('  %s' % pycompat.sysstr(f))
   > EOF
 
   $ ( testrepohgenv; "$PYTHON" wixxml.py help )
   Not installed:
     help/common.txt
     help/hg-ssh.8.txt
     help/hg.1.txt
     help/hgignore.5.txt
     help/hgrc.5.txt
   Not tracked:
 
   $ ( testrepohgenv; "$PYTHON" wixxml.py templates )
   Not installed:
   Not tracked:
 
 #endif
 
-#if virtualenv
-
 Verify that Mercurial is installable with pip. Note that this MUST be
 the last test in this file, because we do some nasty things to the
 shell environment in order to make the virtualenv work reliably.
 
+On Python 3, we use the venv module, which is part of the standard library.
+On Python 2, we use the 3rd party virtualenv module, if available.
+
   $ cd $TESTTMP
+  $ unset PYTHONPATH
+
+#if py3
+  $ "$PYTHON" -m venv installenv >> pip.log
+
+Note: we use this weird path to run pip and hg to avoid platform differences,
+since it's bin on most platforms but Scripts on Windows.
+  $ ./installenv/*/pip install --no-index $TESTDIR/.. >> pip.log
+  $ ./installenv/*/hg debuginstall || cat pip.log
+  checking encoding (ascii)...
+  checking Python executable (*) (glob)
+  checking Python version (3.*) (glob)
+  checking Python lib (*)... (glob)
+  checking Python security support (*) (glob)
+  checking Mercurial version (*) (glob)
+  checking Mercurial custom build (*) (glob)
+  checking module policy (*) (glob)
+  checking installed modules (*/mercurial)... (glob)
+  checking registered compression engines (*) (glob)
+  checking available compression engines (*) (glob)
+  checking available compression engines for wire protocol (*) (glob)
+  checking "re2" regexp engine \((available|missing)\) (re)
+  checking templates ($TESTTMP/installenv/*/site-packages/mercurial/templates)... (glob)
+  checking default template ($TESTTMP/installenv/*/site-packages/mercurial/templates/map-cmdline.default) (glob)
+  checking commit editor... (*) (glob)
+  checking username (test)
+  no problems detected
+#endif
+
+#if no-py3 virtualenv
+
 Note: --no-site-packages is deprecated, but some places have an
 ancient virtualenv from their linux distro or similar and it's not yet
 the default for them.
-  $ unset PYTHONPATH
+
   $ "$PYTHON" -m virtualenv --no-site-packages --never-download installenv >> pip.log
   DEPRECATION: Python 2.7 will reach the end of its life on January 1st, 2020. Please upgrade your Python as Python 2.7 won't be maintained after that date. A future version of pip will drop support for Python 2.7. (?)
   DEPRECATION: Python 2.7 will reach the end of its life on January 1st, 2020. Please upgrade your Python as Python 2.7 won't be maintained after that date. A future version of pip will drop support for Python 2.7. More details about Python 2 support in pip, can be found at https://pip.pypa.io/en/latest/development/release-process/#python-2-support (?)
+
 Note: we use this weird path to run pip and hg to avoid platform differences,
 since it's bin on most platforms but Scripts on Windows.
   $ ./installenv/*/pip install --no-index $TESTDIR/.. >> pip.log
   DEPRECATION: Python 2.7 will reach the end of its life on January 1st, 2020. Please upgrade your Python as Python 2.7 won't be maintained after that date. A future version of pip will drop support for Python 2.7. (?)
   DEPRECATION: Python 2.7 will reach the end of its life on January 1st, 2020. Please upgrade your Python as Python 2.7 won't be maintained after that date. A future version of pip will drop support for Python 2.7. More details about Python 2 support in pip, can be found at https://pip.pypa.io/en/latest/development/release-process/#python-2-support (?)
   $ ./installenv/*/hg debuginstall || cat pip.log
   checking encoding (ascii)...
   checking Python executable (*) (glob)
-  checking Python version (2.*) (glob) (no-py3 !)
-  checking Python version (3.*) (glob) (py3 !)
+  checking Python version (2.*) (glob)
   checking Python lib (*)... (glob)
   checking Python security support (*) (glob)
     TLS 1.2 not supported by Python install; network connections lack modern security (?)
     SNI not supported by Python install; may have connectivity issues with some servers (?)
   checking Mercurial version (*) (glob)
   checking Mercurial custom build (*) (glob)
   checking module policy (*) (glob)
   checking installed modules (*/mercurial)... (glob)
   checking registered compression engines (*) (glob)
   checking available compression engines (*) (glob)
   checking available compression engines for wire protocol (*) (glob)
   checking "re2" regexp engine \((available|missing)\) (re)
   checking templates ($TESTTMP/installenv/*/site-packages/mercurial/templates)... (glob)
   checking default template ($TESTTMP/installenv/*/site-packages/mercurial/templates/map-cmdline.default) (glob)
   checking commit editor... (*) (glob)
   checking username (test)
   no problems detected
 #endif