[PROOF OF CONCEPT] Use venv module to create the base Python where it's present

tests/test_cmdline.py

@@ -21,7 +21,7 @@ def get_src(path):
 
 def test_commandline_basic(tmpdir):
     """Simple command line usage should work and files should be generated"""
-    home_dir, lib_dir, inc_dir, bin_dir = virtualenv.path_locations(str(tmpdir.join("venv")))
+    home_dir, lib_dir, inc_dir, bin_dir = virtualenv.path_locations(str(tmpdir.join("ve")))
     subprocess.check_call([sys.executable, VIRTUALENV_SCRIPT, home_dir])
 
     assert os.path.exists(home_dir)
@@ -42,7 +42,7 @@ def _check_no_warnings(module):
 
 def test_commandline_explicit_interp(tmpdir):
     """Specifying the Python interpreter should work"""
-    subprocess.check_call([sys.executable, VIRTUALENV_SCRIPT, "-p", sys.executable, str(tmpdir.join("venv"))])
+    subprocess.check_call([sys.executable, VIRTUALENV_SCRIPT, "-p", sys.executable, str(tmpdir.join("ve"))])
 
 
 # The registry lookups to support the abbreviated "-p 3.5" form of specifying
@@ -54,4 +54,4 @@ def test_commandline_explicit_interp(tmpdir):
 def test_commandline_abbrev_interp(tmpdir):
     """Specifying abbreviated forms of the Python interpreter should work"""
     abbrev = "{}{}.{}".format("" if sys.platform == "win32" else "python", *sys.version_info[0:2])
-    subprocess.check_call([sys.executable, VIRTUALENV_SCRIPT, "-p", abbrev, str(tmpdir.join("venv"))])
+    subprocess.check_call([sys.executable, VIRTUALENV_SCRIPT, "-p", abbrev, str(tmpdir.join("ve"))])

tests/test_virtualenv.py

@@ -356,7 +356,7 @@ def test_install_python_bin():
 def test_always_copy_option():
     """Should be no symlinks in directory tree"""
     tmp_virtualenv = tempfile.mkdtemp()
-    ve_path = os.path.join(tmp_virtualenv, "venv")
+    ve_path = os.path.join(tmp_virtualenv, "ve")
     try:
         virtualenv.create_environment(ve_path, symlink=False)
 

tests/test_zipapp.py

@@ -59,7 +59,7 @@ def test_wheel_basic_invocation(call_wheel, tmp_path):
 
 
 def _test_basic_invocation(make_env, tmp_path):
-    venv = tmp_path / "venv"
+    venv = tmp_path / "ve"
     make_env(str(venv))
     assert_venv_looks_good(
         venv, list(sys.version_info), "{}{}".format(virtualenv.EXPECTED_EXE, ".exe" if virtualenv.IS_WIN else "")
@@ -83,7 +83,7 @@ def assert_venv_looks_good(venv, version_info, exe_name):
 
 
 def _test_invocation_dash_p(make_env, tmp_path):
-    venv = tmp_path / "venv"
+    venv = tmp_path / "ve"
     python = {2: _python("3"), 3: _python("2.7")}[sys.version_info[0]]
     make_env(str(venv), python)
     expected = {3: 2, 2: 3}[sys.version_info[0]]

virtualenv.py

@@ -1331,6 +1331,22 @@ def install_python(home_dir, lib_dir, inc_dir, bin_dir, site_packages, clear, sy
         print("Please use the *system* python to run this script")
         return
 
+    try:
+        import venv
+    except ImportError:
+        venv = None
+
+    if venv:
+        assert sys.version_info[0] == 3
+        builder = venv.EnvBuilder(system_site_packages=site_packages, clear=clear, symlinks=False, with_pip=False)
+        env_dir = os.path.abspath(home_dir)
+        context = builder.ensure_directories(env_dir)
+        builder.create_configuration(context)
+        # TODO: For Python 3.7.2, the work of setup>python is done in setup_scripts :-()
+        builder.setup_python(context)
+        # TODO: Look at whether we need to skip setting up our site.py and distutils hacks
+        return context.env_exe
+
     if clear:
         rm_tree(lib_dir)
         # FIXME: why not delete it?