Use uv for installing dynamic dependencies in mypy_test.py and regr_test.py (#11517)

tests/regr_test.py

@@ -25,13 +25,12 @@ from parse_metadata import get_recursive_requirements, read_metadata
 from utils import (
     PYTHON_VERSION,
     PackageInfo,
-    VenvInfo,
     colored,
     get_all_testcase_directories,
     get_mypy_req,
-    make_venv,
     print_error,
     testcase_dir_from_package_name,
+    venv_python,
 )
 
 ReturnCode: TypeAlias = int
@@ -148,13 +147,16 @@ def setup_testcase_dir(package: PackageInfo, tempdir: Path, verbosity: Verbosity
         shutil.copytree(Path("stubs", requirement), new_typeshed / "stubs" / requirement)
 
     if requirements.external_pkgs:
-        pip_exe = make_venv(tempdir / VENV_DIR).pip_exe
+        venv_location = str(tempdir / VENV_DIR)
+        subprocess.run(["uv", "venv", venv_location], check=True, capture_output=True)
         # Use --no-cache-dir to avoid issues with concurrent read/writes to the cache
-        pip_command = [pip_exe, "install", get_mypy_req(), *requirements.external_pkgs, "--no-cache-dir"]
+        uv_command = ["uv", "pip", "install", get_mypy_req(), *requirements.external_pkgs, "--no-cache-dir"]
         if verbosity is Verbosity.VERBOSE:
-            verbose_log(f"{package.name}: Setting up venv in {tempdir / VENV_DIR}. {pip_command=}\n")
+            verbose_log(f"{package.name}: Setting up venv in {venv_location}. {uv_command=}\n")
         try:
-            subprocess.run(pip_command, check=True, capture_output=True, text=True)
+            subprocess.run(
+                uv_command, check=True, capture_output=True, text=True, env=os.environ | {"VIRTUAL_ENV": venv_location}
+            )
         except subprocess.CalledProcessError as e:
             _PRINT_QUEUE.put(f"{package.name}\n{e.stderr}")
             raise
@@ -193,7 +195,7 @@ def run_testcases(
         env_vars["MYPYPATH"] = os.pathsep.join(map(str, custom_typeshed.glob("stubs/*")))
         has_non_types_dependencies = (tempdir / VENV_DIR).exists()
         if has_non_types_dependencies:
-            python_exe = VenvInfo.of_existing_venv(tempdir / VENV_DIR).python_exe
+            python_exe = str(venv_python(tempdir / VENV_DIR))
         else:
             python_exe = sys.executable
             flags.append("--no-site-packages")