feat: ensure creation of python3.exe and python3 on Windows (#2957)

Signed-off-by: Emre Şafak <3928300+esafak@users.noreply.github.com>
Co-authored-by: google-labs-jules[bot] <161369871+google-labs-jules[bot]@users.noreply.github.com>

Author: esafak

docs/changelog/2774.feature.rst

@@ -0,0 +1 @@
+Ensure python3.exe and python3 on Windows for Python 3. - by :user:`esafak`.

src/virtualenv/create/via_global_ref/builtin/cpython/common.py

@@ -38,7 +38,10 @@ def _executables(cls, interpreter):
         # - https://bugs.python.org/issue42013
         # - venv
         host = cls.host_python(interpreter)
-        for path in (host.parent / n for n in {"python.exe", host.name}):
+        names = {"python.exe", host.name}
+        if interpreter.version_info.major == 3:  # noqa: PLR2004
+            names.update({"python3.exe", "python3"})
+        for path in (host.parent / n for n in names):
             yield host, [path.name], RefMust.COPY, RefWhen.ANY
         # for more info on pythonw.exe see https://stackoverflow.com/a/30313091
         python_w = host.parent / "pythonw.exe"

tests/unit/create/via_global_ref/builtin/cpython/test_cpython3_win.py

@@ -99,3 +99,11 @@ def test_no_python_zip_if_not_exists(py_info, mock_files):
     sources = tuple(CPython3Windows.sources(interpreter=py_info))
     assert python_zip in py_info.path
     assert not contains_ref(sources, python_zip)
+
+
+@pytest.mark.parametrize("py_info_name", ["cpython3_win_embed"])
+def test_python3_exe_present(py_info, mock_files):
+    mock_files(CPYTHON3_PATH, [py_info.system_executable])
+    sources = tuple(CPython3Windows.sources(interpreter=py_info))
+    assert contains_exe(sources, py_info.system_executable, "python3.exe")
+    assert contains_exe(sources, py_info.system_executable, "python3")