Actually build the zipapp

tests/conftest.py

@@ -20,6 +20,7 @@ from typing import (
     Union,
 )
 from unittest.mock import patch
+from zipfile import ZipFile
 
 import pytest
 
@@ -32,6 +33,7 @@ from _pytest.config import Config
 from _pytest.config.argparsing import Parser
 from setuptools.wheel import Wheel
 
+from pip import __file__ as pip_location
 from pip._internal.cli.main import main as pip_entry_point
 from pip._internal.locations import _USE_SYSCONFIG
 from pip._internal.utils.temp_dir import global_tempdir_manager
@@ -529,6 +531,35 @@ def script_factory(
     return factory
 
 
+ZIPAPP_MAIN = """\
+#!/usr/bin/env python
+
+import os
+import runpy
+import sys
+
+lib = os.path.join(os.path.dirname(__file__), "lib")
+sys.path.insert(0, lib)
+
+runpy.run_module("pip", run_name="__main__")
+"""
+
+def make_zipapp_from_pip(zipapp_name: Path) -> None:
+    pip_dir = Path(pip_location).parent
+    with zipapp_name.open("wb") as zipapp_file:
+        zipapp_file.write(b"#!/usr/bin/env python\n")
+        with ZipFile(zipapp_file, "w") as zipapp:
+            for pip_file in pip_dir.rglob("*"):
+                if pip_file.suffix == ".pyc":
+                    continue
+                if pip_file.name == "__pycache__":
+                    continue
+                rel_name = pip_file.relative_to(pip_dir.parent)
+                zipapp.write(pip_file, arcname=f"lib/{rel_name}")
+            zipapp.writestr("__main__.py", ZIPAPP_MAIN)
+
+
+
 @pytest.fixture(scope="session")
 def zipapp(request: pytest.FixtureRequest, tmpdir_factory: pytest.TempPathFactory) -> Optional[str]:
     """
@@ -542,13 +573,7 @@ def zipapp(request: pytest.FixtureRequest, tmpdir_factory: pytest.TempPathFactor
 
     temp_location = tmpdir_factory.mktemp("zipapp")
     pyz_file = temp_location / "pip.pyz"
-    # What we want to do here is `pip wheel --wheel-dir temp_location <source_dir>`
-    # and then build a zipapp from that wheel.
-    # TODO: Remove hard coded file
-    za = "pip-22.2.dev0.pyz"
-    import warnings
-    warnings.warn(f"Copying {za} to {pyz_file}")
-    shutil.copyfile(za, pyz_file)
+    make_zipapp_from_pip(pyz_file)
     return str(pyz_file)