test: Move create_file() helper and add script.temporary_file() (#13712)

This will be useful for requirements/constraints files.

Author: ichard26

tests/lib/__init__.py

@@ -35,6 +35,7 @@
 from pip._internal.models.target_python import TargetPython
 from pip._internal.network.session import PipSession
 
+from tests.lib.filesystem import create_file
 from tests.lib.venv import VirtualEnvironment
 from tests.lib.wheel import make_wheel
 
@@ -51,18 +52,6 @@
 _FilesState = dict[str, Union[FoundDir, FoundFile]]
 
 
-def create_file(path: str, contents: str | None = None) -> None:
-    """Create a file on the path, with the given contents"""
-    from pip._internal.utils.misc import ensure_dir
-
-    ensure_dir(os.path.dirname(path))
-    with open(path, "w") as f:
-        if contents is not None:
-            f.write(contents)
-        else:
-            f.write("\n")
-
-
 def make_test_search_scope(
     find_links: list[str] | None = None,
     index_urls: list[str] | None = None,
@@ -769,6 +758,12 @@ def assert_installed_editable(self, dist_name: str) -> None:
             and x.get("editable_project_location")
         )
 
+    def temporary_file(self, filename: str, contents: str) -> pathlib.Path:
+        """Create a temporary file with the given filename and contents."""
+        path = self.scratch_path.joinpath(filename)
+        create_file(path, contents)
+        return path
+
 
 # FIXME ScriptTest does something similar, but only within a single
 # ProcResult; this generalizes it so states can be compared across

tests/lib/filesystem.py

@@ -31,3 +31,14 @@ def chmod(path: str | Path, mode: int) -> Iterator[None]:
         yield
     finally:
         os.chmod(path, old_mode)
+
+
+def create_file(path: str | Path, contents: str | None = None) -> None:
+    """Create a file on the path, with the given contents"""
+    _path = Path(path)
+    _path.parent.mkdir(exist_ok=True, parents=True)
+    with _path.open("w") as f:
+        if contents is not None:
+            f.write(contents)
+        else:
+            f.write("\n")

tests/unit/test_req_uninstall.py

@@ -19,7 +19,7 @@
     uninstallation_paths,
 )
 
-from tests.lib import create_file
+from tests.lib.filesystem import create_file
 
 
 # Pretend all files are local, so UninstallPathSet accepts files in the tmpdir,